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Organ Development (organ + development)
Selected AbstractsMi-2 chromatin remodeling factor functions in sensory organ development through proneural gene repression in DrosophilaDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 7 2006Yasutoyo Yamasaki Mi-2, the central component of the nucleosome remodeling and histone deacetylation (NuRD) complex, is known as an SNF2-type ATP-dependent nucleosome remodeling factor. No morphological mutant phenotype of Drosophila Mi-2 (dMi-2) had been reported previously; however, we found that rare escapers develop into adult flies showing an extra bristle phenotype. The dMi-2 enhanced the phenotype of acHw49c, which is a dominant gain-of-function allele of achaete (ac) and produces extra bristles. Consistent with these observations, the ac -expressing proneural clusters were expanded, and extra sensory organ precursors (SOP) were formed in the dMi-2 mutant wing discs. Immunostaining of polytene chromosomes showed that dMi-2 binds to the ac locus, and dMi-2 and acetylated hisotones distribute on polytene chromosomes in a mutually exclusive manner. The chromatin immunoprecipitation assay of the wing imaginal disc also demonstrated a binding of dMi-2 on the ac locus. These results suggest that the Drosophila Mi-2/NuRD complex functions in neuronal differentiation through the repression of proneural gene expression by chromatin remodeling and histone deacetylation. [source] Correlation between Musashi-1 and c-hairy-1 expression and cell proliferation activity in the developing intestine and stomach of both chicken and mouseDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 8 2005Rieko Asai Musashi-1 (Msi-1) is an RNA-binding protein that plays key roles in the maintenance of neural stem cell states and in their differentiation into neural cells. Msi-1 has also been proposed as a candidate marker gene of mammalian intestinal stem cells and their immediate lineages. In this study, we examined Msi-1 expression in the small intestine and the stomach of both chicken and mouse during embryonic, fetal and postnatal development. In addition, we analyzed the expression of c-hairy-1, a chicken homologue of mouse Hes1, and assessed the proliferative activity of the cells expressing both of these factors. Significantly, during the development of these digestive organs in both species Msi-1 expression showed dynamic changes, suggesting that it is important for digestive organ development, particularly for epithelial differentiation. Based on our observations of the expression patterns of Msi-1 and c-hairy-1 in the adult small intestine, we speculate that Msi-1 is also a stem cell marker of the chicken small intestinal epithelium. [source] Establishment of a chick embryo model for analyzing liver development and a search for candidate genesDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2005Yuji Yokouchi The liver plays a crucial role in metabolism. There is considerable interest in how the liver develops, as such knowledge could prove of importance in regenerative medicine. However, our understanding of liver development remains somewhat limited. We have developed a model system using the chick embryo that is cost effective and is easy to manipulate experimentally. We performed four fundamental studies: (i) construction of an atlas of the developing chick liver; (ii) identification of differentiation marker genes in the developing chick embryo; (iii) development of germ-layer specific electroporation; and (iv) establishment of organ culture from the developing chick liver. Using this system, we have been able to demonstrate the functions of candidate genes within a shorter period and in a more cost-effective manner. In parallel with the establishment of this system, we examined the expression patterns of genes known to be required for organ development in the developing chick embryo in order to identify genes also involved in liver development. To date, we have found sixteen genes that are expressed in the developing chick liver (GELD, genes expressed in liver development). This knowledge will be fundamental to the establishment of the basic technology for engineering liver tissue in the future. [source] Recombinant EDA or Sonic Hedgehog rescue the branching defect in Ectodysplasin A pathway mutant salivary glands in vitroDEVELOPMENTAL DYNAMICS, Issue 10 2010K.L. Wells Abstract Hypohidrotic ectodermal dysplasia (HED) is characterized by defective ectodermal organ development. This includes the salivary glands (SGs), which have an important role in lubricating the oral cavity. In humans and mice, HED is caused by mutations in Ectodysplasin A (Eda) pathway genes. Various phenotypes of the mutant mouse EdaTa/Ta, which lacks the ligand Eda, can be rescued by maternal injection or in vitro culture supplementation with recombinant EDA. However, the response of the SGs to this treatment has not been investigated. Here, we show that the submandibular glands (SMGs) of EdaTa/Ta mice exhibit impaired branching morphogenesis, and that supplementation of EdaTa/Ta SMG explants with recombinant EDA rescues the defect. Supplementation of EdardlJ/dlJ SMGs with recombinant Sonic hedgehog (Shh) also rescues the defect, whereas treatment with recombinant Fgf8 does not. This work is the first to test the ability of putative Eda target molecules to rescue Eda pathway mutant SMGs. Developmental Dynamics 239:2674,2684, 2010. © 2010 Wiley-Liss, Inc. [source] Wnt6 expression in epidermis and epithelial tissues during Xenopus organogenesisDEVELOPMENTAL DYNAMICS, Issue 3 2008Danielle L. Lavery Abstract Here, we report the localization within embryonic tissues of xWnt6 protein; together with the temporal and spatial expression of Xenopus laevis Wnt6 mRNA. Wnt6 expression in Xenopus embryos is low until later stages of neurulation, when it is predominantly found in the surface ectoderm. Wnt6 expression increases during early organogenesis in the epidermis overlaying several developing organs, including the eye, heart, and pronephros. At later stages of development, Wnt6 mRNA and protein generally localize in epithelial tissues and specifically within the epithelial tissues of these developing organs. Wnt6 localization correlates closely with sites of both epithelial to mesenchymal transformations and mesenchymal to epithelial transformations. Xenopus Wnt6 sequence and its expression pattern are highly conserved with other vertebrates. Xenopus embryos, therefore, provide an excellent model system for investigating the function of vertebrate Wnt6 in organ development and regulation of tissue architecture. Developmental Dynamics 237:768,779, 2008. © 2008 Wiley-Liss, Inc. [source] Redundant function of the heparan sulfate 6-O-endosulfatases Sulf1 and Sulf2 during skeletal developmentDEVELOPMENTAL DYNAMICS, Issue 2 2008Andreas Ratzka Abstract Modification of the sulfation pattern of heparan sulfate (HS) during organ development is thought to regulate binding and signal transduction of several growth factors. The secreted sulfatases, Sulf1 and Sulf2, desulfate HS on 6-O-positions extracellularly. We show that both sulfatases are expressed in overlapping patterns during embryonic skeletal development. Analysis of compound mutants of Sulf1 and Sulf2 derived from gene trap insertions and targeted null alleles revealed subtle but distinct skeletal malformations including reduced bone length, premature vertebrae ossification and fusions of sternebrae and tail vertebrae. Molecular analysis of endochondral ossification points to a function of Sulf1 and Sulf2 in delaying the differentiation of endochondral bones. Penetrance and severity of the phenotype increased with reduced numbers of functional alleles indicating redundant functions of both sulfatases. The mild skeletal phenotype of double mutants suggests a role for extracellular modification of 6-O-sulfation in fine-tuning rather than regulating the development of skeletal structures. Developmental Dynamics 237:339,353, 2008. © 2008 Wiley-Liss, Inc. [source] Runx3 is involved in hair shape determinationDEVELOPMENTAL DYNAMICS, Issue 4 2005Eli Raveh Abstract Transcriptional regulators of the Runx family play critical roles in normal organ development and, when mutated, lead to genetic diseases and cancer. Runx3 functions during cell lineage decisions in thymopoiesis and neurogenesis and mediates transforming growth factor-, signaling in dendritic cells. Here, we study the function of Runx3 in the skin and its appendages, primarily the hair follicle, during mouse development. Runx3 is expressed predominantly in the dermal compartment of the hair follicles as they form and during the hair cycle, as well as in the nail and sweat gland skin appendages. Distinct expression is also detected periodically in isolated cells of the epidermis and in melanocytes, populating the hair bulb. Runx3 -deficient mice display a perturbation of the normal hair coat, which we show to be due to hair type and hair shape changes. Thus, one of the functions of Runx3 in skin may be to regulate the formation of the epithelial derived structural hair by affecting dermal to epidermal interactions. Developmental Dynamics 233:1478,1487, 2005. © 2005 Wiley-Liss, Inc. [source] Expression of zebrafish six1 during sensory organ development and myogenesisDEVELOPMENTAL DYNAMICS, Issue 4 2004Dmitri A. Bessarab Abstract Drosophila sine oculis homologous genes in vertebrates are homeobox-containing transcription factors functioning within the Pax-Six-Eya-Dach regulatory network during development. In this study, we describe the cloning and expression of a zebrafish homolog of sine oculis, six1. The reverse transcription-polymerase chain reaction demonstrated accumulation of six1 transcripts at mid-gastrula, and in situ hybridization showed their subsequent expression in the cranial placode and later in the olfactory, otic, and lateral line placodes, inner ear, and neuromasts. In addition, six1 is expressed in the pituitary, branchial arches, somites, pectoral fin, ventral abdomen muscle, and the cranial muscles of the eye and lower jaw. An increase of six1 expression was observed in the lateral line, muscles, and inner ear of the mind bomb mutant, illustrating a regulatory effect of the Notch pathway on expression of Six genes. Developmental Dynamics 230:781,786, 2004 © 2004 Wiley-Liss, Inc. [source] Effects of bisphenol A and tetrabromobisphenol A on sex organ development in quail and chicken embryosENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2001Cecilia Berg Abstract The plastic monomere bisphenol A (BPA) and the flame retardant tetrabromobisphenol A (TBBPA) were examined for estrogen-like developmental effects on the reproductive organs in avian embryos. The synthetic estrogen diethylstilbestrol (DES) was used as a positive control. The test compounds were injected into the yolk of quail and chicken eggs early during incubation and the embryos were examined 2 d before anticipated hatching. At 200 ,g/g egg, BPA induced Müllerian duct (embryonic oviduct) malformation in female quail embryos and feminization of the left testis (ovotestis) in male chicken embryos. The estrogenic potency of BPA compared with DES was species and endpoint specific. Müllerian duct malformation was the most sensitive endpoint in quail embryos, whereas ovotestis formation was the most sensitive response in chicken embryos. Tetrabromobisphenol A caused high embryo mortality at 45 ,g/g egg in both species, but no estrogen-like effects were observed. Bisphenol A caused mortality only in chicken embryos at 67 and 200 ,g/g egg. To our knowledge, this is the first report on estrogen-like or embryolethal effects of BPA and TBBPA in birds. [source] Exposure of pacific herring to weathered crude oil: Assessing effects on ova,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2000Mark G. Carls Abstract In order to determine if exposure to Exxon Valdez oil would adversely affect progeny, reproductively mature Pacific herring were confined in water contaminated with weathered crude oil. Progeny were generally not affected by a 16-d parental exposure to initial aqueous concentrations of ,58 ,g/L total polynuclear aromatic hydrocarbons (PAHs), yielding concentrations of up to 9.7 ,g/g in ova. In contrast, previous research indicated that a 16-d direct exposure of herring eggs to similarly weathered oil was detrimental to developing embryos at total initial PAH concentrations of 9 ,g/L. Progeny of exposed fish could have been insulated from toxic effects for two reasons. First, as an apparent result of partitioning and metabolism in parental tissues, lower concentrations and less toxic PAHs were preferentially accumulated by ova (primarily naphthalenes; 84,92%). Second, peak exposure concentrations occurred before cell differentiation. The opposite was true for directly exposed eggs; the more toxic multi-ring PAHs (e.g., phenanthrenes and chrysenes) and alkyl-substituted homologues were accumulated, and internal concentrations increased during cell division, differentiation, and organ development. Thus, Pacific herring embryos are more critically sensitive to oil pollution than are gametes. [source] Testing putative hemichordate homologues of the chordate dorsal nervous system and endostyle: expression of NK2.1 (TTF-1) in the acorn worm Ptychodera flava (Hemichordata, Ptychoderidae)EVOLUTION AND DEVELOPMENT, Issue 6 2002Carter M. Takacs SUMMARY Recent phylogenetic investigations have confirmed that hemichordates and echinoderms are sister taxa. However, hemichordates share several cardinal characteristics with chordates and are thus an important taxon for testing hypotheses of homology between key chordate characters and their putative hemichordate antecedents. The chordate dorsal nervous system (DNS) and endostyle are intriguing characters because both hemichordate larval and adult structures have been hypothesized as homologues. This study attempts to test these purported homologies through examination of the expression pattern of a Ptychodera flava NK2 gene, PfNK2.1, because this gene is expressed both in the DNS and endostyle/thyroid in a wide range of chordate taxa. We found that PfNK2.1 is expressed in both neuronal and pharyngeal structures, but its expression pattern is broken up into distinct embryonic and juvenile phases. During embryogenesis, PfNK2.1 is expressed in the apical ectoderm, with transcripts later detected in presumable neuronal structures, including the apical organ and ciliated feeding band. In the developing juvenile we detected PfNK2.1 signal throughout the pharynx, including the stomochord, and later in the hindgut. We conclude that the similar utilization of NK2.1 in apical organ development and chordate DNS is probably due to a more general role for NK2.1 in neurogenesis and that hemichordates do not possess a homologue of the chordate DNS. In addition, we conclude that P. flava most likely does not possess a true endostyle; rather during the evolution of the endostyle NK2.1 was recruited from its more general role in pharynx development. [source] Inhibition of the lymphotoxin pathway as a therapy for autoimmune diseaseIMMUNOLOGICAL REVIEWS, Issue 1 2008Jeffrey L. Browning Summary: The lymphotoxin (LT) system is part of the tumor necrosis factor family and is required for lymph node development. It has provided a wonderful tool for the dissection of processes critical not only for lymphoid organ development but also the maintenance of the adult immune architecture and the formation of ectopic organized lymphoid tissues in chronically inflamed sites. A soluble lymphotoxin-, receptor-immunoglobulin (LT,R-Ig) fusion protein can block this pathway and is currently being tested in the treatment of autoimmune disease. This review focuses on the immunological consequences of combined LT and LIGHT inhibition with LT,R-Ig administration as distinct from the developmental biology. [source] Contribution of endothelial cells to organogenesis: a modern reappraisal of an old Aristotelian conceptJOURNAL OF ANATOMY, Issue 4 2007E. Crivellato Abstract It is well established that many tissue-derived factors are involved in blood vessel formation, but evidence is now emerging that endothelial cells themselves represent a crucial source of instructive signals to non-vascular tissue cells during organ development. Thus, endothelial cell signalling is currently believed to promote fundamental cues for cell fate specification, embryo patterning, organ differentiation and postnatal tissue remodelling. This review article summarizes some of the recent advances in our understanding of the role of endothelial cells as effector cells in organ formation. [source] Dietary oligochitosan supplementation enhances immune status of broilersJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2007Rui-Lin Huang Abstract Oligochitosan (COS) is a type of prebiotic, which favourably alters the intestinal microflora balance, inhibits the growth of harmful bacteria, promotes good digestion and boosts immune function. The effect of dietary COS supplementation on immune function in broilers was assessed by feeding graded levels (0, 50, 100, 150 mg kg,1) of COS. Two thousand four hundred male commercial Avian® broilers (1 day old) were assigned randomly to five dietary treatment groups (60 birds/pen with eight pens per treatment). Diet A was a typical maize- and soybean meal-based diet supplemented with 6 mg kg,1 antibiotics of flavomycin (positive control). Diet B was the basal diet without any supplement. Diets C, D and E were formulated by addition of 50, 100, 150 mg kg,1 of COS to the basal diet, respectively. On the morning of days 21 and 42, a total of 64 (eight birds/pen with eight pens per treatment) of the growth experimental birds were killed by cervical dislocation, respectively for determination of serum concentrations of IgG, IgA and IgM, and weights of spleen, bursa and thymus. Compared with broilers fed the control and the positive control diets, dietary supplementation with COS increased (P < 0.001) serum concentrations of IgG, IgA, and IgM, with the greatest response for the 100 mg kg,1COS supplementation. Chitosan oligosaccharides supplementation also enhanced the immune organ development. Results suggest COS can improve immune response in birds. Through positive modulation of the immune response, COS has great potential as an effective, antibiotic-like growth promoter for poultry. Copyright © 2006 Society of Chemical Industry [source] The expression and promoter specificity of the birch homologs for PISTILLATA/GLOBOSA and APETALA3/DEFICIENSPHYSIOLOGIA PLANTARUM, Issue 2 2005Mika Lännenpää B-function genes determine the identity of petals and stamens in the flowers of model plants such as Arabidopsis and Antirrhinum. Here, we show that a putative B-function gene BpMADS2, a birch homolog for PISTILLATA, is expressed in stamens and carpels of birch inflorescences. We also present a novel birch gene BpMADS8, a homolog for APETALA3/DEFICIENS, which is expressed in stamens. Promoter-GUS analysis revealed that BpMADS2 promoter is active in the receptacle of Arabidopsis flower buds while BpMADS8 promoter is highly specific in mature stamens. BpMADS2 promoter::BARNASE construct prevented floral organ development in Arabidopsis and tobacco. In birch, inflorescences with degenerated stamens and carpels were obtained. BpMADS8::BARNASE resulted in degeneration of stamens in Arabidopsis and birch causing male sterility. In tobacco, only sepals were developed instead of normal flowers. The results show that the BpMADS2::BARNASE construct can be used to specifically disrupt floral organ development in phylogenetically distant plant species. The stamen-specific promoter of BpMADS8 is a promising tool for biotechnological applications in inducing male sterility or targeting gene expression in the late stamen development. [source] MADS-Box Genes Controlling Flower Development in RicePLANT BIOLOGY, Issue 1 2003F. Fornara Abstract: The separation between monocot and dicot plants occurred about 120 - 180 million years ago and since then major morphological changes have led to the striking differences that can be observed today. To understand whether, despite these differences, the processes controlling flower development are fundamentally comparable in dicot and monocot species, it is necessary to perform comparative studies. However, until recently flower development has been studied mainly in dicot plant species. Genetic and molecular analyses of two dicot model species, Arabidopsis thaliana and Antirrhinum majus, led to the formulation of the ABC model of flower development that describes how the combined activities of three classes of genes are required to drive flower organ development. This model has recently been extended by the inclusion of two other gene classes, namely D and E, which are involved in ovule development, and petal, stamen and carpel development, respectively. Most of the A, B, C, D and E genes identified so far have been shown to encode MADS-box transcription factors. In rice a number of regulatory genes belonging to the MADS-box transcription factor family have been cloned in the last few years and the functions of some of them have been investigated in detail. Here we review the current state of knowledge on rice flower development and focus on MADS-box genes that determine floral organ identity in this species. We compare results obtained in rice with the information known for Arabidopsis and the differences between these two species are discussed. [source] Histological and Ultrastructural Characterization of Developing Miniature Pig Salivary Glands,THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 7 2010Jian Zhou Abstract Salivary glands are a classic model of organ development and differentiation. Miniature pigs are considered as a unique animal model for salivary gland researchers in the fields of gene transfer, radiation damage, and functional reconstruction. However, there is little information about the development of miniature pig salivary glands. The present article was designed to study the developmental stages of salivary glands in miniature pigs using histological and ultrastructural methods. Sections from E40, E60, E80, E95 embryos, and P0 pups were stained with hematoxylin,eosin, Alcian blue, or periodic acid-schiff. Selected specimens were also processed for electron microscopy. The development of the miniature pig salivary glands can be divided into five different stages that refer to the stages of the developing mouse submandibular gland. The histological characteristics of the miniature pig salivary glands at different developmental stages were synchronously verified at the ultrastructural level. Interestingly, the development of the miniature pig parotid gland trailed that of the submandibular gland by ,15 days. Our study provides first-hand data regarding the morphological organogenesis of salivary glands in the miniature pig and provides a foundation for further research on this model. Anat Rec 293:1227,1239, 2010. © 2010 Wiley-Liss, Inc. [source] Identification of CXCL13 as a new marker for follicular dendritic cell sarcoma,THE JOURNAL OF PATHOLOGY, Issue 3 2008W Vermi Abstract The homeostatic chemokine CXCL13 is preferentially produced in B-follicles and is crucial in the lymphoid organ development by attracting B-lymphocytes that express its selective receptor CXCR5. Follicular dendritic cells (FDCs) have been identified as the main cellular source of this chemokine in lymphoid organs. Recently, genome-wide approaches have suggested follicular CD4 T-helper cells (THF) as additional CXCL13 producers in the germinal centre and the neoplastic counterpart of THF (CD4+ tumour T-cells in angioimmunoblastic T-cell lymphoma) retains the capability of producing this chemokine. In contrast, no data are available on CXCL13 expression on FDC sarcoma (FDC-S) cells. By using multiple approaches, we investigated the expression of CXCL13 at mRNA and protein level in reactive and neoplastic FDCs. In reactive lymph nodes and tonsils, CXCL13 protein is mainly expressed by a subset of FDCs in B-cell follicles. CXCL13 is maintained during FDC transformation, since both dysplastic FDCs from 13 cases of Castleman's disease and neoplastic FDCs from ten cases of FDC-S strongly and diffusely express this chemokine. This observation was confirmed at mRNA level by using RT-PCR and in situ hybridization. Of note, no CXCL13 reactivity was observed in a cohort of epithelial and mesenchymal neoplasms potentially mimicking FDC-S. FDC-S are commonly associated with a dense intratumoural inflammatory infiltrate and immunohistochemistry showed that these lymphocytes express the CXCL13 receptor CXCR5 and are mainly of mantle zone B-cell derivation (IgD+ and TCL1+). In conclusion, this study demonstrates that CXCL13 is produced by dysplastic and neoplastic FDCs and can be instrumental in recruiting intratumoural CXCR5+ lymphocytes. In addition to the potential biological relevance of this expression, the use of reagents directed against CXCL13 can be useful to properly identify the origin of spindle cell and epithelioid neoplasms. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Analysis of B function in legumes: PISTILLATA proteins do not require the PI motif for floral organ development in Medicago truncatulaTHE PLANT JOURNAL, Issue 1 2009Reyes Benlloch Summary The B-class gene PISTILLATA (PI) codes for a MADS-box transcription factor required for floral organ identity in angiosperms. Unlike Arabidopsis, it has been suggested that legume PI genes contribute to a variety of processes, such as the development of floral organs, floral common petal,stamen primordia, complex leaves and N-fixing root nodules. Another interesting feature of legume PI homologues is that some of them lack the highly conserved C-terminal PI motif suggested to be crucial for function. Therefore, legume PI genes are useful for addressing controversial questions on the evolution of B-class gene function, including how they may have diverged in both function and structure to affect different developmental processes. However, functional analysis of legume PI genes has been hampered because no mutation in any B-class gene has been identified in legumes. Here we fill this gap by studying the PI function in the model legume species Medicago truncatula using mutant and RNAi approaches. Like other legume species, M. truncatula has two PI homologues. The expression of the two genes, MtPI and MtNGL9, has strongly diverged, suggesting differences in function. Our analyses show that these genes are required for petal and stamen identity, where MtPI appears to play a predominant role. However, they appear not to be required for development of the nodule, the common primordia or the complex leaf. Moreover, both M. truncatula PI homologues lack the PI motif, which indicates that the C-terminal motif is not essential for PI activity. [source] The CLAVATA1-related BAM1, BAM2 and BAM3 receptor kinase-like proteins are required for meristem function in ArabidopsisTHE PLANT JOURNAL, Issue 1 2006Brody J. DeYoung Summary Organ formation at shoot and flower meristems in plants requires the maintenance of a population of centrally located stem cells and the differentiation of peripherally located daughter cells. The CLAVATA (CLV) gene products in Arabidopsis, including the CLV1 receptor-kinase, regulate this process by promoting the differentiation of stem cells on the meristem flanks. Here, we have analyzed the developmental roles of the CLV1-related BAM1 (derived from barely any meristem 1), BAM2 and BAM3 receptor-like kinases. Loss-of-function alleles of these receptors lead to phenotypes consistent with the loss of stem cells at the shoot and flower meristem, suggesting that their developmental role is opposite to that of CLV1. These closely related receptors are further distinguished from CLV1, whose expression and function is highly specific, by having broad expression patterns and multiple developmental roles. These include a requirement for BAM1, BAM2 and BAM3 in the development of high-ordered vascular strands within the leaf and a correlated control of leaf shape, size and symmetry. In addition, BAM1, BAM2 and BAM3 are required for male gametophyte development, as well as ovule specification and function. Significantly, the differing roles of CLV1 and BAM receptors in meristem and organ development are largely driven by differences in expression patterns. [source] Apoptosis and Bcl-2 Protein Expression in Human Placenta over the Course of Normal PregnancyANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2010S. Soni With 2 figures and 2 tables Summary Apoptosis plays a central role in organ development, homeostasis and immune defence in multicellular organisms and is strictly controlled in part by members of Bcl-2 family. The Bcl-2 is a pro-survival molecule identified through its involvement in B-cell lymphomas. The aim of the study was to evaluate the incidence of apoptosis in the human placenta at different stages of pregnancy and to correlate it further with Bcl-2 expression. A total of 96 placental samples from first trimester, mid-trimester and uncomplicated term pregnancies were collected (n = 32 + 32 + 32). M30 cyto death monoclonal antibody was used to identify apoptotic cells. The apoptosis index of first trimester placentae was 2.33 ± 1.70, mid- trimester was 1.77 ± 1.36 and term placenta was 1.15 ± 0.21. Bcl-2 protein was found immunolocalized in the cytoplasm of syncytiotrophoblast. Apoptosis index was significantly reduced in term cases as compared with first trimester (P < 0.002) and mid-trimester placentae (P = 0.01). On the contrary, Bcl-2 expression was significantly higher at term cases than in first trimester (P < 0.0001) and mid-trimester cases (P < 0.001). The present study divulges the importance of apoptosis in permitting normal physiological turnover of villous trophoblast and also exhibits the contribution of bcl-2 in maintaining syncytial integrity throughout normal pregnancy. [source] Current knowledge of microRNA characterization in agricultural animalsANIMAL GENETICS, Issue 3 2010H.-C. Liu Summary MicroRNA (miRNA) is a class of single-stranded small (19,24nt) regulatory RNA that silences gene expression post-transcriptionally. miRNAs regulate a wide range of biological processes through the recognition of complementary sequences between miRNAs and their target genes. Profiling studies in livestock have revealed that many miRNAs are species- and tissue-specific, indicating that miRNAs play important roles in essential biological processes in livestock, such as muscle and organ development, the immune response and metabolism. The allelic variation of miRNA target sites and possibly in miRNAs themselves are also likely to be contributing factors to many phenotypic differences in livestock. In this review, we summarize the current miRNA studies undertaken in livestock. [source] Ontogeny of immune system organs in northern bluefin tuna (Thunnus orientalis, Temminck and Schlegel 1844)AQUACULTURE RESEARCH, Issue 1 2003M Watts Abstract Serial sections, prepared from 0.5 to 30 days posthatch (dph) larval and juvenile Thunnus orientalis (Temminck & Schlegel 1844), were stained with haematoxylin and eosin and examined by light microscopy for immune organ development. The early kidney was present at 0.5 dph, undifferentiated stem cells began to appear at 2 dph, and by 7 dph occasional small lymphocytes were present. The thymus was first obvious at 5 dph, located above the fourth branchial arch, small lymphocytes appeared at 7 dph, and by 15 dph an outer thymocytic zone and an inner epithelioid zone were visible. The progenitor spleen was present at 2 dph, located close to the gut, and by 12 dph it consisted of a mass of sinusoids filled with red blood cells, and remained mainly erythroid throughout the period studied. These results suggest that development of immune organs in this species is precocious relative to other marine teleosts. [source] Sex-specific and left-right asymmetric expression pattern of Bmp7 in the gonad of normal and sex-reversed chicken embryosDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2005Anshin Hoshino A genetic switch determines whether the indifferent gonad develops into an ovary or a testis. In adult females of many avian species, the left ovary is functional while the right one regresses. In the embryo, bone morphogenetic proteins (BMP) mediate biological effects in many organ developments but their roles in avian sex determination and gonadal differentiation remains largely unknown. Here, we report the sex-specific and left-right (L-R) asymmetric expression pattern of Bmp7 in the chicken gonadogenesis. Bmp7 was L-R asymmetrically expressed at the beginning of genital ridge formation. After sexual differentiation occurred, sex-specific expression pattern of Bmp7 was observed in the ovary mesenchyme. In addition, ovary-specific Bmp7 expression was reduced in experimentally induced female-to-male reversal using the aromatase inhibitor (AI). These dynamic changes of expression pattern of Bmp7 in the gonad with or without AI treatment suggest that BMP may play roles in determination of L-R asymmetric development and sex-dependent differentiation in the avian gonadogenesis. 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