A fresh trim provides a new look at the human mannose receptor

The human mannose receptor plays an important role in scavenging a variety of glycans and glycoconjugates, which contributes to both innate and adaptive immunity. However, the fine details of its ligand specificity, and specifically that of carbohydrate-recognition domain 4, the most functionally relevant C-type lectin domain within the receptor, are not completely understood. Feinberg et al. use glycan arrays, crystallography, and a newly trimmed version of carbohydrate-recognition domain 4 to elucidate the molecular mechanisms driving binding specificity. These data contribute to our molecular understanding of Ca²⁺-mediated binding promiscuity in the human mannose receptor and the scavenging role of the receptor itself and highlight unexpected interactions that should inspire further study.     

CMA conference to look at role research plays when critical policy decisions are being made

Physician leaders will meet in Ottawa Feb. 28 and Mar. 1 for the CMA''s 9th Annual Leadership Conference to examine how evidence, research and data influence health policy. For information or to register contact CMA Meetings and Travel Department, 800 663-7336, ext. 2274; fax 613 731-8047.     

Bioturbation: a fresh look at Darwin's last idea

Bioturbation refers to the biological reworking of soils and sediments, and its importance for soil processes and geomorphology was first realised by Charles Darwin, who devoted his last scientific book to the subject. Here, we review some new insights into the evolutionary and ecological role of bioturbation that would have probably amazed Darwin. In modern ecological theory, bioturbation is now recognised as an archetypal example of 'ecosystem engineering', modifying geochemical gradients, redistributing food resources, viruses, bacteria, resting stages and eggs. From an evolutionary perspective, recent investigations provide evidence that bioturbation had a key role in the evolution of metazoan life at the end of the Precambrian Era.     

A fresh look at the open rhinoplasty technique

Use of the open rhinoplasty technique (ORT) in certain nasal and septal deformities has proven to be an invaluable asset in the rhinoplasty armamentarium of the authors. Primarily owing to the markedly increased exposure with this technique, more accurate assessment of the deformities is possible and additional or improved surgical maneuvers become available, particularly in the tip. Sculpting the entire cartilaginous and/or bony vault, as well as correcting difficult septal malalignments, can be carried out under better direct vision with greater precision, accuracy, and predictability. This has led to improved and more consistent final results. Previous criticisms of unsightly columellar scars have been virtually eliminated through the use of improved surgical techniques and simple magnification. Overall, open rhinoplasty technique can provide many distinct advantages in certain nasal deformities with no real disadvantages over conventional closed techniques.     

A fresh look at cancer metabolism in a historical setting

The Institute for Research in Biomedicine (IRB) Barcelona meeting on Cancer Metabolism took place in November 2010. It was organized with the support of the Banco Bilbao Vizcaya Argentaria Foundation and offered an outstanding line-up of acclaimed speakers within an intimate setting that allowed plenty of opportunity for informal interactions.     

A fresh look at the temporal dynamics of binocular rivalry

Human observers viewed dichoptic orthogonal sine-wave gratings and indicated when exclusive visibility occurred in either eye. Contrast was held constant in one eye and was increased or decreased in the other eye for a number of alternation cycles (continuous presentation) or for only the duration of a single period of exclusive visibility (synchronous presentation). The synchronous presentation condition allowed us to identify the differing effects of contrast during the suppressed and during the dominant periods. Mixed phases were recorded as distinct from suppressed and dominant phases, and new classifications of compound-dominant and compound-suppressed phases are defined. The results indicate that binocular rivalry responds to stimulus contrast in two ways. 1) The duty-cycle of dominance and suppression is determined by the relative image contrast between the two eyes, with dominance of the higher contrast image being favored, and 2) the overall rate of alternation is driven by monocular image contrast during the suppressed phase (increased monocular contrast increases the alternation rate) and to a lesser extent by monocular contrast during the dominant phase (increased monocular contrast decreases the rate). A model is developed to reflect these ideas. These results support a reciprocal inhibition oscillator as the underlying mechanism of binocular rivalry.     

A fresh look at the origin of Plasmodium falciparum, the most malignant malaria agent

From which host did the most malignant human malaria come: birds, primates, or rodents? When did the transfer occur? Over the last half century, these have been some of the questions up for debate about the origin of Plasmodium falciparum, the most common and deadliest human malaria parasite, which is responsible for at least one million deaths every year. Recent findings bring elements in favor of a transfer from great apes, but are these evidences really solid? What are the grey areas that remain to be clarified? Here, we examine in depth these new elements and discuss how they modify our perception of the origin and evolution of P. falciparum. We also discuss the perspectives these new discoveries open.     

Cladoendesis and a new look at the evolution of insect metamorphosis

Cladoendesis is a method of phylogeny analysis opposed to various matrix methods. In contrast to matrix methods, in cladoendesis phylogenetic trees are not built each time as new ones, but are reconstructed based on the previous results. Each character of each taxon is compared with its ancestral condition in the ground-plan of the higher taxon. The revealed part of the phylogeny is represented in a form of hierarchical classification. In addition to the principles of natural classification elaborated by C. Linnaeus, P.-A. Latreille, and others, evolutionary theory elaborated by Ch. Darwin and others, and principles of phylogenetic systematics elaborated by W. Hennig and others, cladoendesis includes rank-free dual nomenclature system (DualNom) and advanced method of text layout elaborated by the author. Important components of cladoendesis are the use of the term “plesiomorphon” and taking into account such important evolutionary events as conservation and deconservation of characters. Cladoendesis allowed the author to make comprehensive revision of the phylogeny of Ephemeroptera, find homology in the structure of the maxillae of adult Aphaniptera, larval maxillae of Neuropteroidea-Birostrata, larval legs of Nannomecoptera, and genital parts of some insect taxa. It also allows understanding the nature and evolution of insect metamorphosis. It is generally believed that initially insect ontogenesis proceeds the shortest way, while such phenomena as substitutions of organs by means of their atrophy and subsequent restoring are secondary. In contrast to this, the flagellum of the antenna of Amyocerata initially grows by addition of proximal segments and simultaneous loss of distal ones; in many taxa, including Metabola (insects with complete metamorphosis), distal segments are not aborted. Some authors tried to explain the origin of complete metamorphosis by various reasons: ecological, morphogenetic, or others. This approach is wrong because all insects with complete metamorphosis constitute the holophyletic taxon Metabola Burmeister 1832, i.e., originate from a single ancestral species which acquired this kind of metamorphosis. If complete metamorphosis could appear in response to some factor, it would appear many times in different species, in which case the taxon Metabola, characterized by complete metamorphosis, would be polyphyletic. The holophyly of Metabola is well proven by cladoendesis but cannot be revealed by any matrix method. Based on understanding of these facts, the author was able to discover the specific features which appeared in the common ancestor of Metabola and then became conserved and were inherited by all its descendants. These features include loss of the scape in the larval antenna (leading to a peculiar transformation of antennae in metamorphosis) and a peculiar mode of leg transformation during molt from larva to pupa. During the larval/pupal molt, the leg loses musculature and gets an immobile knee bend, so that the pupa is unable to use its legs. This conserved feature determines the inactive mode of life of the pupae of most insects. It is usually believed that male coccids (Gallinsecta De Geer 1776) have metamorphosis similar to the complete metamorphosis of Metabola. But the phylogenetic position of Gallinsecta and Metabola, as revealed by cladoendesis, does not allow one to assume common modifications in their metamorphoses. Now, when concrete autapomorphies of Metabola have been found, it becomes possible to compare metamorphoses of Metabola and Gallinsecta. Examination of Orthezia urticae and some other coccids shows that metamorphosis of their males shares no modifications with the true complete metamorphosis. The inactive mode of life of their nymphs is not connected with any anatomical reason, but purely with the fact that in the course of transformation from the feeding wingless larva to the non-feeding winged adult, the nymph has already lost its mouth apparatus and has not yet got functional wings, so it does not need to move. At the same time, actively feeding stages of Gallinsecta, both males and females, have an unusual mode of molt transformation of the legs and antennae; this is a unique autapomorphy of Gallinsecta not found in any other insect taxon.     

Obesity and the labor market: A fresh look at the weight penalty

This paper applies semiparametric regression models to shed light on the relationship between body weight and labor market outcomes in Germany. We find conclusive evidence that these relationships are poorly described by linear or quadratic OLS specifications. Women's wages and employment probabilities do not follow a linear relationship and are highest at a body weight far below the clinical threshold of obesity. This indicates that looks, rather than health, is the driving force behind the adverse labor market outcomes to which overweight women are subject. Further support is lent to this notion by the fact that wage penalties for overweight and obese women are only observable in white-collar occupations. On the other hand, bigger appears to be better in the case of men, for whom employment prospects increase with weight, albeit with diminishing returns. However, underweight men in blue-collar jobs earn lower wages because they lack the muscular strength required in such occupations.