Nipping the Cambrian "explosion" in the bud?

In recent years, two schools of thought have emerged with regard to the Cambrian "explosion". One argues that it was very quick, with phyla tumbling into existence in a virtual geological instant. The other view has a more relaxed temporal perspective. It looks to slow aeons of cryptic metazoan history, which led to a final breakthrough in the Cambrian, not in evolution but of fossilization potential. Yet both views have serious difficulties. Now, in a recent issue of Biological Reviews, Graham Budd and S?ren Jensen(1) argue for a third way. In an intriguing blend of functional morphology, the fossil record and cladistic thinking, they suggest that the assembly of metazoan bodyplans took place in a surprisingly straightforward manner.     

Will the "new biology" affect the future of histopathology?

The technologies used in histopathology are changing as a consequence of the current revolutionary progress in several areas of biology. It is likely that general cancer management will improve because of the impact of molecular techniques and immunohistochemistry on tumor diagnosis and classification and on the determination of prognosis and response to therapy. Moreover, as therapies are starting to be modelled after the distinctive molecular characteristics of a specific tumor, the availability of molecular tests to all patients will become a matter of great importance.     

Is the "nonspecific" thalamus still "nonspecific"?

The classical concept of "nonspecific" thalamus, as distinguished from the principal thalamic nuclei (i.e. the primary sensory, motor and limbic relays) is here briefly revisited in the light of anatomical investigations performed in the last decades, and primarily those based on tract tracing techniques. Altogether these data pointed out that the so-called "nonspecific" thalamus is composed by a heterogeneous collection of nuclear masses, which display not only species differences, but also marked internuclear variations in their cytological and neurochemical features, connections, areal and laminar distribution upon the cortex, and functional properties. Thus, the "nonspecific" thalamus exerts a modulatory role on cortical activity, chiefly regulated at the intrathalamic level by the interplay between the thalamic reticular nucleus and the interneurons and projection neurons of the dorsal thalamus. However, each of the components that have been traditionally considered as "nonspecific" also subserves selective roles in the transfer of different kinds of information from the thalamus to the cerebral cortex and basal ganglia.     

Are the local adjustments of the relative spatial frequencies of the dynein arms and the beta-tubulin monomers involved in the regulation of the "9+2" axoneme?

The “9+2” axoneme is a highly specific cylindrical machine whose periodic bending is due to the cumulative shear of its 9 outer doublets of microtubules. Because of the discrete architecture of the tubulin monomers and the active appendices that the outer doublets carry (dynein arms, nexin links and radial spokes), this movement corresponds to the relative shear of these topological verniers, whose characteristics depend on the geometry of the wave train. When an axonemal segment bends, this induces the compressed and dilated conformations of the tubulin monomers and, consequently, the modification of the spatial frequencies of the appendages that the outer doublets carry. From a dynamic point of view, the adjustments of the spatial frequencies of the elements of the two facing verniers that must interact create different longitudinal periodic patterns of distribution of the joint probability of the molecular interaction as a function of the location of the doublet pairs around the axonemal cylinder and their spatial orientation within the axonemal cylinder. During the shear, these patterns move along the outer doublet intervals at a speed that ranges from one to more than a thousand times that of sliding, in two opposite directions along the two opposite halves of the axoneme separated by the bending plane, respecting the polarity of the dynein arms within the axoneme. Consequently, these waves might be involved in the regulation of the alternating activity of the dynein arms along the flagellum, because they induce the necessary intermolecular dialog along the axoneme since they could be an element of the local dynamic stability/instability equilibrium of the axoneme. This complements the geometric clutch model [Lindemann, C., 1994. A “geometric clutch” hypothesis to explain oscillations of the axoneme of cilia and flagella. J. Theor. Biol. 168, 175-189].     

Mycorrhizal perennials of the "matorral xerófilo" and the "selva baja caducifolia" communities in the semiarid Tehuacán-Cuicatlán Valley,Mexico

We investigated the mycorrhizal status of perennial xeric plant species occurring in the "matorral xerófilo" (arid tropical scrub) and the ecotone of the "selva baja caducifolia" (tropical deciduous forest) communities in the semiarid valley of Tehuacán-Cuicatlán, south-central Mexico. The perennial species examined are dominant/codominant elements within the "matorral xerófilo" and the "selva baja caducifolia", both endangered communities in the Biosphere Reserve Tehuacán-Cuicatlán Valley. Of the 50 sampled species, 45 were mycorrhizal. To our knowledge, we report arbuscular mycorrhizae (AM) for the first time in 37 species, of which 21 are endemic to Mexico and nine are endemic to the Valley. We also report AM for the first time in three genera, Buddleja, Hechtia and Zornia, and in one plant family, Buddlejaceae. Beaucarnea gracilis, a threatened species, and Mimosa purpusii, a potentially rare species, are both mycorrhizal. This is the first study of the mycorrhizal status of plant species within the Valley.     

Do we need the "adolescent crisis" diagnosis?

The aim of the study was to examine patients in adolescent crisis at the beginning of treatment and after a period of 12 months in order to evaluate the relative diagnostic and therapeutic validity. The study included 153 Split University students in adolescent crisis; 90 of them were treated by counseling and 63 served as controls. For diagnosis, Hampstead index and Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) multiaxial evaluation were used, allowing a wider insight into personal functioning. The study sample was split in 7 significantly different diagnostic subgroups. The counseling-treated examinees had better personality functioning after 12 months, but did not differ significantly from the control group. Some of their single functions were more severely disturbed at the very beginning. Counseling is a valuable therapeutic and diagnostic tool for adolescent crisis. The assessment must evaluate the entire person, because looking at only one aspect, due to different development and its place, a wrong conclusion may be reached. The "adolescents crisis" entity is clinically relevant.     

Beta-peptoid "foldamers"--why the additional methylene unit?

The field of peptoid (i.e., N-alkylglycine) research has been thriving since the first publications on this molecular design appeared in 1992. A highly efficient and modular synthetic platform, which is compatible with automation and ready generation of combinatorial libraries, was published the same year. This has enabled the investigation of numerous compounds with this architecture, and ligands with a wide variety of interesting biological targets have thus been discovered. Furthermore, detailed biophysical and structural studies focusing on the investigation of the conformational space adopted and three-dimensional folding of these peptide mimics have been undertaken. The same is true for beta-peptides (i.e., oligomers composed of beta-amino acids). Since the first publication describing peptide mimics combining these two structural modifications [the N-alkyl-beta-alanines (beta-peptoids)] in 1998, on the other hand, the application of this backbone construct has appeared much more sparsely in the literature. The present perspective article will provide an overview of the data obtained for beta-peptoid-containing peptide mimics as well as a discussion of the future challenges associated with this type of backbone modification.     

"Resonances" in the dielectric absorption of DNA?

An attempt was made to confirm previous reports of resonant-like dielectric absorption of plasmid DNA in aqueous solutions at 1-10 GHz. The dielectric properties of the sample were measured using an automatic network analyzer with two different techniques. One technique used an open-ended coaxial probe immersed in the sample; the other employed a coaxial transmission line. No resonances were observed that could be attributed to the sample; however, resonance-type artifacts were prominent in the probe measurements. The coaxial line technique appears to be less susceptible to such artifacts. We note two important sources of error in the calibration of the automatic network analyzer using the probe technique.     

Half-a-century of the "Körmend Growth Study"

The authors give a sketch about the "K?rmend Growth Study" which is series of cross-sectional growth studies, carried out in K?rmend, a small town in Western Hungary. The first investigation was carried out in 1958 (K-58) and it has been repeated every ten years (K-68, K-78, K-88, and K-98). All 3-18 year-old healthy boys and girls in nurseries and schools in K?rmend were involved in the study. Twenty-three body measurements were taken. This paper focuses on changes in height, weight, and BMI. Means of these two body measurements show an increase from time to time (as a phenomenon of positive secular trend), however, the secular trend for increasing height and weight is declining. BMI follows a similar pattern.     

Ukhtomski? and the nature of the human "ego"]

A. Ukhtomski? is one of those Russian naturalists of the beginning of the 20th century (K. Tsiolkovski?, V. Vernadski?, K. Timiriazev, I. Pavlov), whose scientific work is characterized by a combination of the valuable contribution to a specific field of science and deep philosophical conceptualizations. Ukhtomski? enriched modern neurophysiology by the ideas on dominant--a stable focus of enhanced excitability, determining the organism reactions to the environmental stimuli. Unlike artificial experimental models, natural dominant--vector of the goal-directed behaviour--represents the needs of immediate satisfaction, dominating at the present moment. Formation of needs hierarchy, characteristic of the given personality, occurs during the process of people communication. Namely, another man serves to the subject a mirror, looking into which he realizes himself as a human being (K. Marx). By his teaching on the dominant, Ukhtomski? has revealed the dual nature of the personality's self-consciousness in the process of its perception of the surrounding people. He showed that involuntary projection of its dominating vital and social needs (motives, intentions) to the image of another man makes the latter only the "double" of the observer, which does not promote the development and enrichment of personality. Actually productive is only the perception which is motivated by the ideal need of learning another personality, sincere interest in him, what makes another person a "well-deserved colocutor", a source of new knowledge about people and himself. The ideas of Ukhtomski? on the nature of human "self" are close to ideological searchings of L. Tolsto? and F. Dostoevski?.(ABSTRACT TRUNCATED AT 250 WORDS)     

Xenophobia and anti-Semitism in the medical milieu during the Occupation as seen through the journal "Concours Médical"

Analysis of a well-known medical journal, the Concours Médical reveals the attitude among the French medical corps between 1940 and 1944. This journal kept its readers informed of the various stages of xenophobia and anti-Semitism under the Vichy government. It provided the decisions adopted, and the application of measures prohibiting foreign and Jewish physicians to practice, regularly publishing lists. Analysis of the editions published under the occupation clearly shows the xenophobia and anti-Semitism that existed among a certain population of French practitioners.     

Do chondrocytes undergo "activation" and "transdifferentiation" during the pathogenesis of osteoarthritis? A review of the ultrastructural and immunohistochemical evidence

Chondrocytes, which are the only cell type in the articular cartilage, show substantial morphological and functional differences, depending on their location within the tissue. In OA cartilage, outstanding modifications have been reported concerning their structure and functions. Based on the principle that both structure and function run in a parallel manner, new concepts are arising related to morphological observations. Observations on OA chondrocytes, such as cytoskeleton disruption, development of the secretory machinery (rough endoplasmic reticulum and Golgi complex), and cell death by apoptosis, among others, certainly must be related to the role of chondrocytes in OA pathogenesis. In this degradative process, it has been acknowledged that cell death, matrix degradation and subchondral bone remodelling are the main causes of cartilage breakdown in osteoarthritis. The aim of this review was to correlate and integrate in a logical manner the modifications of chondrocytes with cartilage breakdown during osteoarthritis pathogenesis. Furthermore, we intend to open a debate on cell cycle and mitosis, as well as on signalling molecules that might be involved in the morphofunctional changes in OA chondrocytes, which we propose to name "activation" and "transdifferentiation" of chondrocytes. We expect this analysis to be useful for studying OA pathogenesis in depth, with the aim of finding new strategies for the early diagnosis and therapeutic procedures for this invalidating disease, which is already an important public health problem.     

Scientific research at the Laboratoire Arago (Banyuls, France) in the twentieth Century: Edouard Chatton, the "master", and André Lwoff, the "pupil"

Edouard Chatton (1883–1947) began his scientific career in the Pasteur Institute, where he made several important discoveries regarding pathogenic protists (trypanosomids, Plasmodium, toxoplasms, Leishmania). In 1908 he married a "Banyulencque", Marie Herre; from 1920, he focused his research on marine protists. He finished his career as Professor at the Sorbonne (Paris) and director of the Laboratoire Arago in Banyuls-sur-mer, where he died in 1947. André Lwoff (1902–1994) lived several scientific lives in addition to his artistic and family life. But it is the study of protists that filled his first life after he encountered the exceptional Master who was Chatton. Lwoff's father was a psychiatrist and his mother an artist sculptor. He became a Doctor of Medicine in 1927 and then a Doctor of Sciences in 1932, his thesis dealing with biochemical aspects of protozoa nutrition. He met Chatton in 1921 and – until Chatton's death – their meetings, first in Roscoff and then in Banyuls-sur-mer, were numerous and their collaboration very close. Their monograph on apostome ciliates was one of the peaks of this collaboration. In 1938, Lwoff was made director of the Microbial Physiology Department at the Pasteur Institute in Paris, where he began a new life devoted to bacteria, and then to viruses, before pursuing his career as director of the Cancer Research Institute in Villejuif (France). Lwoff was awarded the Nobel Prize in Physiology or Medicine in 1965. He died in Banyuls in 1994. "Master" and "pupil" had in common perseverance in their scientific work, conception and observation, a critical sense and rigor but also a great artistic sensibility that painting and drawing in the exceptional surroundings of Banyuls-sur-mer had fulfilled. Electronic Publication     

DLK: the "preconditioning" signal for axon regeneration?

In this issue of Neuron, Shin et?al. (2012) show that the dual leucine zipper kinase (DLK) is responsible for the retrograde injury signal in spinal sensory and motor neurons. DLK is required for the accelerated regeneration seen after axotomy and for the improved regeneration seen after a conditioning injury. DLK KO axons have severely reduced axon regeneration in?vivo.     

Can the "challenge hypothesis" be applied to insects?

The challenge hypothesis, conceived for testosterone and vertebrates, has recently been applied to juvenile hormone (JH) and insects. Scott [Scott, M.P., 2006a. Resource defense and juvenile hormone: the "challenge hypothesis" extended to insects. Horm. Behav. 49, 276-281] found that JH in the burying beetle Nicrophorus orbicollis increased in response to a social challenge in the presence of a breeding resource, while there was no such JH response in the purported brood parasite Nicrophorus pustulatus. Two important implications of the challenge hypothesis that need to be tested are whether JH affects dominance and why there are interspecific differences in the JH response to a social challenge. The effect of JH on dominance in burying beetles was examined by topical application of JH III to one of two competing females at 24 h and again at 1 h prior to presentation of a breeding resource (mouse carcass). JH supplementation had no effect on dominance in intraspecific interactions in N. orbicollis, as measured by possession of the carcass on Day 1, 3 or 7. Similarly, JH did not alter carcass ownership during competition between N. orbicollis and N. pustulatus nor did it affect reproductive success. Irrespective of JH supplementation, N. pustulatus became increasingly dominant as the trials progressed, rarely occupying the carcass on Day 1, but excluding N. orbicollis in nearly half the trials by Day 7. These findings, and a brief review of the burying beetle literature, suggest that the challenge hypothesis, as applied to testosterone and vertebrates, does not yet have an analogous model for JH and insects.