Genetic and developmental aspects of neuroendocrine regulation investigated by Eugene Naumenko and his colleagues

Olfactory-mediated choice behavior in mice: Developmental and genetic aspects

The development of apomixis technology in crop plants is a desirable goal. Apomixis is the asexual reproduction through seeds, which occurs in over 400 flowering plants (Nogler, 1984). The introduction of clonal reproduction to crop plants will allow the indefinite propagation of any desirable genotype (including that of heterozygous F1 hybrids) and will completely transform current breeding and seed production strategies. Developmental aspects of apomixis (Koltunow, 1993; Grossniklaus, 2001; Spillane et al., 2001), its genetic control (Savidan, 2000; Grossniklaus et al., 2001a; Grimanelli et al., 2001), and its potential use in agriculture (Koltunow et al., 1995; Hanna et al., 1998; Jefferson and Bicknell, 1996; Thoenissen, 2001) have been extensively reviewed. Here, we provide a short summary of developmental and genetic aspects and report on our program using sexual model systems to identify genes and promoters relevant to the engineering of apomixis.

Differences in sex development (DSD) in patients with 46,XX karyotype occur by foetal or postnatal exposure to an increased amount of androgens. These disorders are usually diagnosed at birth, in newborns with abnormal genitalia, or later, due to postnatal virilization, usually at puberty. Proper diagnosis and therapy are mostly based on the knowledge of normal development and molecular etiopathogenesis of the gonadal and adrenal structures. This review aims to describe the most relevant data that are correlated with the normal and abnormal development of adrenal and gonadal structures in direct correlation with their utility in clinical practice, mainly in patients with 46,XX karyotype. We described the prenatal development of structures together with the main molecules and pathways that are involved in sex development. The second part of the review described the physical, imaging, hormonal and genetic evaluation in a patient with a disorder of sex development, insisting more on patients with 46,XX karyotype. Further, 95% of the etiology in 46,XX patients with disorders of sex development is due to congenital adrenal hyperplasia, by enzyme deficiencies that are involved in the hormonal synthesis pathway. The other cases are explained by genetic abnormalities that are involved in the development of the genital system. The phenotypic variability is very important in 46,XX disorders of sex development and the knowledge of each sign, even the most discreet, which could reveal such disorders, mainly in the neonatal period, could influence the evolution, prognosis and life quality long term.

A variant of Lycopersion esculentum var. cerasiforme is described that deviates from the typical form of the entire species, including cultivated tomatoes, in possessing high levels (500-5000 micrograms/g of dry weight) of the steroidal alkaloid alpha-tomatine in its ripe fruits. This biotype is restricted to a tiny enclave in the valley of Río Mayo, Department San Martín, Peru. Among 88 accessions of var. cerasiforme from its present distribution in the Andes, a 90% association was found between high tomatine and bitter flavor; within the Mayo watershed, all samples from the upper drainage had bitterness and high tomatine; the frequency of both traits decreased to low levels toward the lower end. Tomatine therefore probably is the source of bitterness. Throughout L. esculentum tomatine is present at very high concentrations in earliest stages of fruit development, thereafter decreasing rapidly to midperiod, and finally diminishing gradually to near zero at maturity as a result of catabolism to biologically inert compounds, except in the variant described here. High tomatine content does not appear to affect adversely either the natives, among whom the bitter types are popular, or individuals who sampled them in this survey. Genetic determination of high tomatine in ripe fruits is totally recessive and appears to be monogenic with interaction with genes of minor effect. The prevailing pattern of glycoalkaloid synthesis and degradation in development of solanaceous fruits suggests a mechanism to protect against predation prior to ripening but to permit it afterward as a device to promote dispersal. In consideration of the nondegradative nature of the variant, its genetic determination, and very restricted geographic distribution, mutation to this form appears to be a random event of doubtful evolutionary significance.

Echinococcus: Biology and strain variation

The concept of canalization was used by Waddington (66) in the context of developmental biology. He emphasized two important points in the develop­ ment of higher organisms. First, the end products of development, i.e. the adult tissues, are of sharply distinct types without intergradation. Second, the normal course of development is in his view a preferred path. Deviations of this path due to disturbances in the internal or external environment are corrected by regulatory processes. This occurs not only in the development of distinct types of tissue, but also on the organismic level in the realization of morphological patterns, in size and shape of organs and in matters of growth and determination of size of whole organisms. He depicted these phenomena in what he called the epigenetic landscape. Development starts in the egg. From there numerous developmental pathways branch out, leading to a great variety of distinct end results. These pathways are represented as a system of branching valleys in a descending slope. The developmental process is visual­ ized as balls rolling through the valleys to their end point. The steeper the valley and the larger the ridges separating the valleys, the stronger the tendency of the ball, when it is pushed from its course along the valley bottom by internal or external disturbances, to go back to its original course. This

Canalization: Genetic And Developmental Aspects

The past, present and future of social neuroscience: A European perspective

Impairment of interleukin-1 (IL-1) signaling reduces basal pain sensitivity in mice: genetic, pharmacological and developmental aspects

Pediatric and Reproductive Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, U.S.A.

ADAMs (a disintegrin and metalloprotease) are membrane-bound enzymes, capable of shedding a multitude of proteins from the surface of the cell. They are therefore considered crucial modulators of physiological and pathophysiological processes. The structure and function of ADAMs is related to those of a family of snake venom metalloproteases which also possess a potential adhesion domain as well as a potential protease domain. Mammalian ADAMs are involved in various biological and disease-related processes, such as cell-cell fusion, adhesion and intracellular signalling. Functional involvement has been described in sperm-egg binding and fusion, trophoblast invasion and matrix degradation during pregnancy, angiogenesis and neovascularization. Clinically, ADAMs are implicated in pathological processes, including cancer, inflammation, neurodegeneration and fibrosis, through shedding of the apoptosis-inducing FAS ligand, cytokines and growth factors. A second group of proteins within the ADAM family has recently been discovered. These contain several thrombospondin-like repeats in their C-terminal regions, in the absence of the transmembrane domain known to be present in ADAMs. These proteins were called the ADAMTS (ADAM with thrombospondin domains) family. The relevance of ADAMTS enzymes has become evident in patients with a deficiency in ADAMTS-13, a von Willebrand factor cleaving protease. These patients develop thrombotic thrombocytopenic purpura, a devastating thrombotic disorder caused by widespread microvascular thrombi composed of platelets and von Willebrand factor (VWF). Here we focus on the genetic, developmental, functional and disease-related aspects of ADAMs and ADAMTS. Finally we discuss the perspectives of the therapeutical potential of ADAMs in disease.

BackgroundThe zebrafish, Danio rerio, is used as a model organism to study vertebrate genetics and development. An effective enhancer trap (ET) in zebrafish using the Tol2 transposon has been demonstrated. This approach could be used to study embryogenesis of a vertebrate species in real time and with high resolution.DescriptionThe information gathered during the course of systematic investigation of many ET transgenic lines have been collected and compiled in the form of an online database – the Zebrafish Enhancer TRAP lines database (ZETRAP).ConclusionZETRAP is a web-based system that provides data and information to the scientific community about the developmental, genetic and genomic aspects of transgenic zebrafish lines obtained using Tol2 transposon-mediated transgenesis. The current version (version 1.0) contains description of 27 ET lines that express EGFP in various organs and tissues, for example, heart, brain, notochord, gut, etc. It also includes information on insertion sites of the Tol2 transposon in these lines.

Agenesis of the corpus callosum (AgCC), a failure to develop the large bundle of fibres that connect the cerebral hemispheres, occurs in 1:4000 individuals. Genetics, animal models and detailed structural neuroimaging are now providing insights into the developmental and molecular bases of AgCC. Studies using neuropsychological, electroencephalogram and functional MRI approaches are examining the resulting impairments in emotional and social functioning, and have begun to explore the functional neuroanatomy underlying impaired higher-order cognition. The study of AgCC could provide insight into the integrated cerebral functioning of healthy brains, and may offer a model for understanding certain psychiatric illnesses, such as schizophrenia and autism.

Biology of Citrus provides a concise and comprehensive discussion of all major developmental, genetic and horticultural aspects of citriculture in an easily readable text. The book deals with the history, distribution and climatic adaptation of the crop, followed by taxonomy and systematics, including a horticultural classification of edible citrus species. Subsequent chapters cover tree structure and function, reproductive physiology, including flowering, fruiting, productivity, ripening, post-harvest and fruit constituents. The main aspects of cultivated citrus, such as rootstocks, irrigation, pests, viruses and diseases are dealt with, leading to a concluding chapter that considers genetic improvement, including the use of tissue culture and plant biotechnology. The book includes many specially produced original illustrations and the extensive reading lists will make it invaluable for students and citrus specialists.

PERHAPS the most significant feature of the current efforts to improve the curricular offerings in secondaryschool science and mathematics is the interest shown in the problem by scientists and mathematicians in higher education and industry. Possibly this interest has always been there, lying dormant, but now these men and women have had machinery provided which not only allows secondary-school teachers and supervisory personnel to meet and discuss their problems with scientists but also has permitted scientists to work with the schools in developing new programs which are being tried in the classroom. In biology, the central effort toward the development of new secondary-school courses is being directed by the Biological Sciences Curriculum Study. The BSCS is sponsored by The American Institute of Biological Sciences, representing more than 80,000 biologists, and is supported financially by grants from the National Science Foundation. Quite independently of the BSCS instructional materials, a number of schools have developed excellent programs of their own. The increasing number of schools throughout the country that will be doing something significantly different in biology instruction over the next several years presents a real challenge to the colleges whose job it is to prepare teachers who will be trained to do a competent job in these new programs. It now behooves any institution of higher learning, which has as one of its roles the preparation of teachers of biology for the secondary schools, to recognize quickly the import of the revolution that is occurring on the secondary level and to participate in a searching self-examination to see whether it is indeed ready to assume the responsibility for preparing teachers of these new curricular offerings. It is too often assumed that the colleges and universities are naturally the educational pacemakers in a given field of science. But this can be true only as long as colleges continue to improve their own science programs in response to new stimuli from both scientific and educational sources. I think we must admit that, in a number of institutions now preparing teachers, the biology programs have tended to become ossified. The course offerings have not changed essentially in a generation. They still have a taxonomic-morphological orientation, emphasizing nomenclature and descriptive organic diversity at the expense of the study of basic concepts which stress features common to all living matter. Introductory college biology which consists primarily of an extensive survey of the plant and animal kingdoms is hardly defensible today. The morphology of organisms and their classification are of course important, but they should not be studied as if they were the essence of the subject to the exclusion of the physiological, genetic, developmental, ecological, behavioral and evolutionary aspects of living matter. It seems appropriate to suggest several questions which teacher-training institutions might ask themselves and which might make a productive, if embarrassing, outline for discussion when college and secondary-school people sit down together to consider their problems in this area.