Diet and metabolic development

For many years, investigators have been concerned with mechanisms that control and alter genetically regulated development. An intriguing aspect of these mechanisms is the ability of environmental factors to induce certain metabolic processes. Animal studies have shown that dietary manipulation of cholesterol and fatty acid metabolism during development can have persistent and permanent effects. In addition, there appears to be a critical period when changes in the diet can have lasting consequences. The changes in the control exerted by nutritional factors on metabolic development coincide with three phases of development: prenatal, suckling, and weaning. The effects of diet on cholesterol and fatty acid metabolism throughout these three phases of development will be addressed in this review.     

Stem cell function during plant vascular development

While many regulatory mechanisms controlling the development and function of root and shoot apical meristems have been revealed, our knowledge of similar processes in lateral meristems, including the vascular cambium, is still limited. Our understanding of even the anatomy and development of lateral meristems (procambium or vascular cambium) is still relatively incomplete, let alone their genetic regulation. Research into this particular tissue type has been mostly hindered by a lack of suitable molecular markers, as well as the fact that thus far very few mutants affecting plant secondary development have been described. The development of suitable molecular markers is a high priority in order to help define the anatomy, especially the location and identity of cambial stem cells and the developmental phases and molecular regulatory mechanisms of the cambial zone. To date, most of the advances have been obtained by studying the role of the major plant hormones in vascular development. Thus far auxin, cytokinin, gibberellin and ethylene have been implicated in regulating the maintenance and activity of cambial stem cells; the most logical question in research would be how these hormones interact during the various phases of cambial development.     

Life is a journey: a genetic look at neocortical development

Although the basic principles of neocortical development have been known for quite some time, it is only recently that our understanding of the molecular mechanisms that are involved has improved. Such understanding has been facilitated by genetic approaches that have identified key proteins involved in neocortical development, which have been placed into signalling pathways by molecular and cell-biological studies. The challenge of current research is to understand the manner in which these various signalling pathways are interconnected to gain a more comprehensive picture of the molecular intricacies that govern neocortical development.     

Concanavalin a and wheat germ agglutinin receptors on dictyostelium: Their visualization by scanning electron microscopy with microspheres

The cellular slime mold, Dictyostelium discoideum, is a convenient model for studying cellular interactions during development. Evidence that specific cell surface components are involved in cellular interactions during its development has been obtained by Gerisch and co-workers (1, 2) using immunological techniques. Smart and Hynes (3) have shown that a cell surface protein can be iodinated on cells in aggregation phase, but not in vegetative phase, by the lactoperoxidase procedure. Recently, McMahon et al. (4), and Hoffman and McMahon have demonstrated, by SDS gel electrophoresis, considerable differences in cell surface proteins and glycoproteins of plasma membranes isolated from cells at different stages of development. Plant lectins have also been used to monitor changes in cell surface properties of D. discoideum cells during development. Weeks and co-workers (5, 6) have detected differences in the binding and agglutination of cells by concanavalin A (Con A). Gillette and Filosa (7) have shown that Con A inhibits cell aggregation and prematurely induces cyclic AMP phosphodiesterase. Capping of Con A receptors has also been reported (8). Reitherman et al. (9) have recently reported that agglutination of cells by several plant lectins and the slime mold agglutination, discoidin, changes during development. Such studies indicate that differences in surface properties exist for cells at various stages of development. However, owing to the uncertainties in the factors which contribute to lectin-induced cell agglutination (10), the molecular basis for these observations remain to be determined. In this study, we have used microspheres (11-14) coupled to either Con A or wheat germ agglutinin (WGA) as visual markers to study by scanning electron microscopy the topographical distribution of lectin receptors on D. discoideum cells fixed at different stages of development. We also describe the effect of labeling on the distribution of lectin receptors and on the morphology of the cell surface.     

Somatic cell nuclear transfer: Past, present and future perspectives

It is now over a decade since the birth, in 1996, of Dolly the first animal to be produced by nuclear transfer using an adult derived somatic cell as nuclear donor. Since this time similar techniques have been successfully applied to a range of species producing live offspring and allowing the development of transgenic technologies for agricultural, biotechnological and medical uses. However, though applicable to a range of species, overall, the efficiencies of development of healthy offspring remain low. The low frequency of successful development has been attributed to incomplete or inappropriate reprogramming of the transferred nuclear genome. Many studies have demonstrated that such reprogramming occurs by epigenetic mechanisms not involving alterations in DNA sequence, however, at present the molecular mechanisms underlying reprogramming are poorly defined. Since the birth of Dolly many studies have attempted to improve the frequency of development, this review will discuss the process of animal production by nuclear transfer and in particular changes in the methodology which have increased development and survival, simplified or increased robustness of the technique. Although much of the discussion is applicable across species, for simplicity we will concentrate primarily on published data for cattle, sheep, pigs and mice.     

Branching,segmentation and the metapterygial axis: pattern versus process in the vertebrate limb

Explanations of the patterns of vertebrate fin and limb evolution are improving as specific hypotheses based on molecular and developmental data are proposed and tested. Comparative analyses of gene expression patterns and functions in developing limbs, and morphological patterns in embryonic, adult and fossil limbs point to digit specification as a key developmental innovation associated with the origin of tetrapods. Digit development during the fin-to-limb transition involved sustained proximodistal outgrowth and a new phase of Hox gene expression in the distal fin bud. These patterning changes in the distal limb have been explained by the linked concepts of the metapterygial axis and the digital arch. These have been proposed to account for the generation of limb pattern by sequential branching and segmentation of precartilagenous elements along the proximodistal axis of the limb. While these ideas have been very fruitful, they have become increasingly difficult to reconcile with experimental and comparative studies of fin and limb development. Here we argue that limb development does not involve a branching mechanism, and reassess the concept of a metapterygial axis in limb development and evolution.     

Characteristics of detection of the general direction of movement of visual objects by preschool-age children with typical and atypical cognitive development

The specifics of functioning of two channels for processing visual information, the magnocellular and parvocellular ones, in preschool children with normal and impaired cognitive development have been studied. Children with delayed psychological development have been found to have a diminished activity in the magnocellular channel due to weakening of the mechanism responsible for assessing the temporal parameters of the visual input. At the same time, children displaying a spectrum of infantile autism syndromes complicated by a delayed psychological development and mental retardation have a pronounced deficit in information processing in both channels of the visual system, manifested in an impaired ability to assess the direction of movement in terms of both temporal and spatial characteristics of the objects. The degree of this impairment is correlated with both the severity of the particular neurological disorder and the level of speech development of the child.     

Drug discovery and development for neglected parasitic diseases

Diseases caused by tropical parasites affect hundreds of millions of people worldwide but have been largely neglected for drug development because they affect poor people in poor regions of the world. Most of the current drugs used to treat these diseases are decades old and have many limitations, including the emergence of drug resistance. This review will summarize efforts to reinvigorate the drug development pipeline for these diseases, which is driven in large part by support from major philanthropies. The organisms responsible for these diseases have a fascinating biology, and many potential biochemical targets are now apparent. These neglected diseases present unique challenges to drug development that are being addressed by new consortia of scientists from academia and industry.     

Commodifying Development Experience: Deconstructing Development as Gift in the Development Blockbuster

This paper discusses the recent rise of popular ‘blockbuster’ books written by international development industry insiders and produced by commercial publishers. The paper explores a set of common stylistic devices found within this emerging genre. Though each book is different, a key trope is the story of an author's earlier professional life—the hard lessons and gritty insights that have supposedly emerged from it—that normally underpins each narrative. By living the challenges involved in development work at first hand, and by making mistakes and experiencing epiphanies along the way, these author-professionals want readers to know that they have found out the hard way that long-cherished beliefs about development now need to be questioned. Readers are invited to relive these lessons and epiphanies, and to think and act differently about development by upholding a highly pragmatic form of development professionalism. Combining elements of research monograph, self-help book and personal memoir, these development blockbuster books can be understood not only as commodities, but also as part of the development gift. The authors promise a gift of experience but, in reality, these books are mundane commodities enmeshed in capitalist exchange relations.     

Neuronal polarization is impaired in mice lacking RhoE expression

Proper development of neuronal networks relies on the polarization of the neurons, thus the establishment of two compartments, axons and dendrites, whose formation depends on cytoskeletal rearrangements. Rnd proteins are regulators of actin organization and they are important players in several aspects of brain development as neurite formation, axon guidance and neuron migration. We have recently demonstrated that mice lacking RhoE/Rnd3 expression die shortly after birth and have neuromotor impairment and neuromuscular alterations, indicating an abnormal development of the nervous system. In this study, we have further investigated the specific role played by RhoE in several aspects of neuronal development by using hippocampal neuron cultures. Our findings show that neurons from a mice lacking RhoE expression exhibit a decrease in the number and the total length of the neurites. We also show that RhoE-deficient neurons display a reduction in axon outgrowth and a delay in the process of neuronal polarization. In addition, our results suggest an involvement of the RHOA/ROCK/LIMK/COFILIN signaling pathway in the neuronal alterations induced by the lack of RhoE. These findings support our previous report revealing the important role of RhoE in the normal development of the nervous system and may provide novel therapeutic targets in neurodegenerative disorders.     

Testing models of dental development in the earliest bony vertebrates, Andreolepis and Lophosteus

Theories on the development and evolution of teeth have long been biased by the fallacy that chondrichthyans reflect the ancestral condition for jawed vertebrates. However, correctly resolving the nature of the primitive vertebrate dentition is challenged by a dearth of evidence on dental development in primitive osteichthyans. Jaw elements from the Silurian-Devonian stem-osteichthyans Lophosteus and Andreolepis have been described to bear a dentition arranged in longitudinal rows and vertical files, reminiscent of a pattern of successional development. We tested this inference, using synchrotron radiation X-ray tomographic microscopy (SRXTM) to reveal the pattern of skeletal development preserved in the sclerochronology of the mineralized tissues. The tooth-like tubercles represent focal elaborations of dentine within otherwise continuous sheets of the dermal skeleton, present in at least three stacked generations. Thus, the tubercles are not discrete modular teeth and their arrangement into rows and files is a feature of the dermal ornamentation that does not reflect a polarity of development or linear succession. These fossil remains have no bearing on the nature of the dentition in osteichthyans and, indeed, our results raise questions concerning the homologies of these bones and the phylogenetic classification of Andreolepis and Lophosteus.     

Ageing and cancer as diseases of epigenesis

Cancer and ageing are often said to be diseases of development. During the past fifty years, the genetic components of cancer and ageing have been intensely investigated since development, itself, was seen to be an epiphenomenon of the genome. However, as we have learned more about the expression of the genome, we find that differences in expression can be as important as differences in alleles. It is easier to inactivate a gene by methylation than by mutation, and given that appropriate methylation is essential for normal development, one can immediately see that diseases would result as a consequence of inappropriate epigenetic methylation. While first proposed by Boris Vanyushin in 1973, recent studies have confirmed that inappropriate methylation not only causes diseases, and it also may be the critical factor in ageing and cancers.     

Gap junctional communication in the developing central nervous system

The development of the central nervous system is a complex process involving multiple interactions between various cell types undergoing mitosis, migration, differentiation, axonal outgrowth, synaptogenesis and programmed cell death. For example, neocortical development is characterized by a series of transient events that ultimately leads to the formation of a discrete pattern of laminar and columnar organization. While neuron-glial cell-cell interactions have been shown to be involved in neuronal migration, recent observations that neurons are extensively coupled by gap junctions in the developing neocortex have implicated this phenomenon in the process of neocortical differentiation. The present review will examine the putative role of gap junctional intercellular communication in development of the central nervous system, with specific reference to recent studies in the development of the cerebral cortex.     

A putative G protein-coupled receptor negatively controls sexual development in Aspergillus nidulans

G protein-coupled receptors (GPCRs) are key components of heterotrimeric G protein-mediated signalling pathways that detect environmental signals and confer rapid cellular responses. To broaden our understanding of signalling mechanisms in the filamentous fungus Aspergillus nidulans, intensive analyses of the Aspergillus nidulans genome have been carried out and nine genes (gprA approximately gprI) that are predicted to encode seven transmembrane spanning GPCRs have been identified. Six of nine putative GPCRs have been disrupted and the gprD gene was found to play a central role in coordinating hyphal growth and sexual development. Deletion of gprD (Delta gprD) causes extremely restricted hyphal growth, delayed conidial germination and uncontrolled activation of sexual development resulting in a small colony covered by sexual fruiting bodies. Genetic studies indicate that GprD may not signal through the FadA (G alpha)-protein kinase A (PKA) pathway. Elimination of sexual development rescues both growth and developmental abnormalities caused by Delta gprD, suggesting that the primary role of GprD is to negatively regulate sexual development. This is supported by the fact that environmental conditions inhibiting sexual development suppress growth defects of the Delta gprD mutant. We propose that the GprD-mediated signalling cascade negatively regulates sexual development, which is required for proper proliferation of A. nidulans.     

Sustainability indicator development—Science or political negotiation?

The efforts to develop sustainability indicators have strongly increased since the beginning of the 1990s, often led by intergovernmental processes. More recently, a number of sustainability indicator development processes have been initiated within large research projects that aim to design tools for sustainability assessments, funded by the European Union. The development of sustainability indicators provides a particular challenge to scientists, given the essentially normative dimension of the concept of “sustainability”. Thus, we argue, the development of sustainability indicators is a process of both scientific “knowledge production” and of political “norm creation”, and both components need to be properly acknowledged. Based on a respective theoretical framework and comparing five cases of sustainability indicator development processes (three science-led and two led by intergovernmental processes), we find that the political norm creation dimension is not fully and explicitly recognized in science-led processes. The paper concludes by discussing a number of implications for the design of sustainability indicator development processes, in particular with regard to participation and representation as well as adjustment of indicators over time.     

Functions of Noncoding RNAs in Neural Development and Neurological Diseases

The development of the central nervous system (CNS) relies on precisely orchestrated gene expression regulation. Dysregulation of both genetic and environmental factors can affect proper CNS development and results in neurological diseases. Recent studies have shown that similar to protein coding genes, noncoding RNA molecules have a significant impact on normal CNS development and on causes and progression of human neurological disorders. In this review, we have highlighted discoveries of functions of noncoding RNAs, in particular microRNAs and long noncoding RNAs, in neural development and neurological diseases. Emerging evidence has shown that microRNAs play an essential role in many aspects of neural development, such as proliferation of neural stem cells and progenitors, neuronal differentiation, maturation, and synaptogenesis. Misregulation of microRNAs is associated with some mental disorders and neurodegeneration diseases. In addition, long noncoding RNAs are found to play a role in neural development by regulating the expression of protein coding genes. Therefore, examining noncoding RNA-mediated gene regulations has revealed novel mechanisms of neural development and provided new insights into the etiology of human neurological diseases.