Morphometrics as an insight into processes beyond tooth shape variation in a bank vole population

Phenotype variation is a key feature in evolution, being produced by development and the target of the screening by selection. We focus here on a variable morphological feature: the third upper molar (UM3) of the bank vole, aiming at identifying the sources of this variation. Size and shape of the UM3 occlusal surface was quantified in successive samples of a bank vole population. The first source of variation was the season of trapping, due to differences in the age structure of the population in turn affecting the wear of the teeth. The second direction of variation corresponded to the occurrence, or not, of an additional triangle on the tooth. This intra-specific variation was attributed to the space available at the posterior end of the UM3, allowing or not the addition of a further triangle.This size variation triggering the shape polymorphism is not controlled by the developmental cascade along the molar row. This suggests that other sources of size variation, possibly epigenetic, might be involved. They would trigger an important shape variation as side-effect by affecting the termination of the sequential addition of triangles on the tooth.     

Geographic Structuring of the Plasmodium falciparum Sarco(endo)plasmic Reticulum Ca2+ ATPase (PfSERCA) Gene Diversity

Artemisinin, a thapsigargin-like sesquiterpene has been shown to inhibit the Plasmodium falciparum sarco/endoplasmic reticulum calcium-ATPase PfSERCA. To collect baseline pfserca sequence information before field deployment of Artemisinin-based Combination therapies that may select mutant parasites, we conducted a sequence analysis of 100 isolates from multiple sites in Africa, Asia and South America. Coding sequence diversity was large, with 29 mutated codons, including 32 SNPs (average of one SNP/115 bp), of which 19 were novel mutations. Most SNP detected in this study were clustered within a region in the cytosolic head of the protein. The PfSERCA functional domains were very well conserved, with non synonymous mutations located outside the functional domains, except for the S769N mutation associated in French Guiana with elevated IC₅₀ for artemether. The S769N mutation is located close to the hinge of the headpiece, which in other species modulates calcium affinity and in consequence efficacy of inhibitors, possibly linking calcium homeostasis to drug resistance. Genetic diversity was highest in Senegal, Brazil and French Guiana, and few mutations were identified in Asia. Population genetic analysis was conducted for a partial fragment of the gene encompassing nucleotide coordinates 87-2862 (unambiguous sequence available for 96 isolates). This supported a geographic clustering, with a separation between Old and New World samples and one dominant ancestral haplotype. Genetic drift alone cannot explain the observed polymorphism, suggesting that other evolutionary mechanisms are operating. One possible contributor could be the frequency of haemoglobinopathies that are associated with calcium dysregulation in the erythrocyte.     

Dissecting cellulitis of the scalp

Dissecting cellulitis of the scalp or perifolliculitis capitis abscedens et suffodiens is a rare, chronic, progressive, suppurative disease of the scalp of unknown etiology. It is characterized by painful nodules, purulent drainage, burrowing interconnecting abscesses, and cicatricial alopecia. The pathogenesis is unknown, although it is probably related to follicular occlusion, secondary infection, and deep inflammation. Black men in their second to fourth decade are predominantly affected. Treatment varies from systemic antibiotics to incision and drainage, x-ray epilation of the affected areas, systemic steroid administration, and surgical excision. Our experience with four patients with extensive scalp disease is presented. Wide excision of the affected areas and splitthickness skin graft are favored as our treatment of choice.     

Identification of sequence homology between human plasma apolipoprotein B-100 and apolipoprotein B-48

The structural relationship between apolipoprotein B-100 (apo-B-100) and apolipoprotein B-48 (apo-B-48) has not been elucidated. A peptide fragment (MDB-18) of approximately 6 kDa was isolated from a tryptic digest of apo-B-100. The sequence of the first 22 amino acids of MDB-18 was determined by Edman degradation. A 15-residue peptide corresponding to this sequence was synthesized by the solid-phase method and was utilized to develop a sequence-specific polyclonal antibody. On immunoblot analysis, the antibody recognized both intact apo-B-100 and apo-B-48. In addition, preincubating the antibody with the synthetic peptide abolished the recognition of both apo-B-100 and apo-B-48. These data are interpreted as indicating that there is an amino acid sequence homology between apo-B-100 and apo-B-48. Since the MDB-18 peptide is located in the carboxyl region of the B-100 molecule, we propose apo-B-100 and apo-B-48 share a common carboxyl region sequence.     

Evidence that a locus for familial high myopia maps to chromosome 18p.

Myopia, or nearsightedness, is the most common human eye disorder. A genomewide screen was conducted to map the gene(s) associated with high, early-onset, autosomal dominant myopia. Eight families that each included two or more individuals with >=-6.00 diopters (D) myopia, in two or more successive generations, were identified. Myopic individuals had no clinical evidence of connective-tissue abnormalities, and the average age at diagnosis of myopia was 6.8 years. The average spherical component refractive error for the affected individuals was -9.48 D. The families contained 82 individuals; of these, DNA was available for 71 (37 affected). Markers flanking or intragenic to the genes for Stickler syndrome types 1 and 2 (chromosomes 12q13.1-q13.3 and 6p21.3, respectively), Marfan syndrome (chromosome 15q21.1), and juvenile glaucoma (chromosome 1q21-q31) were also analyzed. No evidence of linkage was found for markers for the Stickler syndrome types 1 and 2, the Marfan syndrome, or the juvenile glaucoma loci. After a genomewide search, evidence of significant linkage was found on chromosome 18p. The maximum LOD score was 9.59, with marker D18S481, at a recombination fraction of .0010. Haplotype analysis further refined this myopia locus to a 7.6-cM interval between markers D18S59 and D18S1138 on 18p11.31.     

Poekilopleuron bucklandii, the theropod dinosaur from the Middle Jurassic (Bathonian) of Normandy

Poekilopleuron bucklandii , described by Eudes–Deslongchamps in 1838, is one of the earliest discovered dinosaurs. Although incomplete, it is one of the best preserved Middle Jurassic theropods known from Europe. Unfortunately, the only specimen of P. bucklandii , housed in the Musée de la Faculté des Sciences de Caen, was destroyed during World War II. However, casts of some parts of the type skeleton have been found in the collections of the Museum National d'Histoire Naturelle, Paris. These casts and Eudes–Deslongchamps' monograph are used to redescribe the specimen. Poekilopleuron shares one synapomorphy with the Spinosauroidea and we tentatively assign it to that clade. The possible synonymy between Poekilopleuron and Megalosaurus is examined and we conclude that Megalosaurus is a nomen dubium and that the name should be restricted to the type dentary.     

The amino acid sequence of human APOA-I, an apolipoprotein isolated from high density lipoproteins.

The complete amino acid sequence of human A-I has been determined by manual and automated Edman degradation of intact and peptide fragments of A-I. A-I is a single chain protein of 243 residues with the following amino acid composition: Asp₁₆, Asn₅, Thr₁₀, Ser₁₅, Glu₂₇, Gln₁₉, Pro₁₀, Gly₁₀, Ala₁₉, Val₁₃, Met₃, Leu₃₇, Tyr₇, Phe₆, Trp₄, Lys₂₁, His₅, and Arg₁₆. The amino acid sequence contains no linear segments of hydrophobic or hydrophilic residues. A detailed correlation of the amino acid sequence, conformation, and self association of A-I will add further insight into the molecular mechanisms involved in protein-protein and protein-lipid interactions.