DLX5, FGF8 and the Pin1 isomerase control ΔNp63α protein stability during limb development: a regulatory loop at the basis of the SHFM and EEC congenital malformations

PubMed Central

Restelli, Michela; Lopardo, Teresa; Lo Iacono, Nadia; Garaffo, Giulia; Conte, Daniele; Rustighi, Alessandra; Napoli, Marco; Del Sal, Giannino; Perez-Morga, David; Costanzo, Antonio; Merlo, Giorgio Roberto; Guerrini, Luisa

2014-01-01

Ectrodactyly, or Split-Hand/Foot Malformation (SHFM), is a congenital condition characterized by the loss of central rays of hands and feet. The p63 and the DLX5;DLX6 transcription factors, expressed in the embryonic limb buds and ectoderm, are disease genes for these conditions. Mutations of p63 also cause the ectodermal dysplasia–ectrodactyly–cleft lip/palate (EEC) syndrome, comprising SHFM. Ectrodactyly is linked to defects of the apical ectodermal ridge (AER) of the developing limb buds. FGF8 is the key signaling molecule in this process, able to direct proximo-distal growth and patterning of the skeletal primordial of the limbs. In the limb buds of both p63 and Dlx5;Dlx6 murine models of SHFM, the AER is poorly stratified and FGF8 expression is severely reduced. We show here that the FGF8 locus is a downstream target of DLX5 and that FGF8 counteracts Pin1–ΔNp63α interaction. In vivo, lack of Pin1 leads to accumulation of the p63 protein in the embryonic limbs and ectoderm. We show also that ΔNp63α protein stability is negatively regulated by the interaction with the prolyl-isomerase Pin1, via proteasome-mediated degradation; p63 mutant proteins associated with SHFM or EEC syndromes are resistant to Pin1 action. Thus, DLX5, p63, Pin1 and FGF8 participate to the same time- and location-restricted regulatory loop essential for AER stratification, hence for normal patterning and skeletal morphogenesis of the limb buds. These results shed new light on the molecular mechanisms at the basis of the SHFM and EEC limb malformations. PMID:24569166

Suppression of morphogenesis in embryonic mouse limbs exposed in vitro to excess gravity

NASA Technical Reports Server (NTRS)

Duke, Jackie C.

1983-01-01

The effect of excess gravity on in vitro mammalian limb chondrogenesis is studied. Limb buds from mice of various gestational stages were exposed to excess gravity (2.6G) using a culture centrifuge. Both forelimbs and hind limbs were cultured, and the development of various limb elements was scored after four to six days. The 2.6G force significantly depressed the development of limb elements when applied during the teratogen-sensitive period of chondrogenesis.

EFFECTS OF ETHANOL AND HYDROGEN PEROXIDE ON MOUSE LIMB BUD MESENCHYME DIFFERENTIATION AND CELL DEATH

EPA Science Inventory

Many of the morphological defects associated with embryonic alcohol exposure are a result of cell death. During limb development, ethanol administration produces cell death in the limb and digital defects, including postaxial ectrodactyly. Because an accumulation of reactive oxyg...

RESISTANCE TO X-IRRADIATION BY EMBRYONIC CELLS OF THE LIMB-BUDS OF TADPOLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen, B.M.; Ewell, L.M.

1959-01-01

Both total-body irradiation and shielding of the trunk were used to study the effects of x irradiation from 1000 to 30000 r upon the limb-buds of Bufo boreas and Hyla regilla tadpoles. The object was to test the view that the younger the cells the more sensitive they are to irradiation. The answer is negative. If there is any special susceptibility of these undifferentiated cells it should appear at levels far below the 30000 r maximum employed. A sharp distinction is made between the very susceptible mitotic cells and the resistant non-dividing embryonic cells that have been accumulated in suchmore » numbers that they may rapidly differentiate into the characteristic limb tissues under the stimulus of the thyroid hormone. Many irradiated ectoderm cells were changed to form bizarre excrescences but were not destroyed. Unicellular cuthneous gland cells continued to arise even after the heaviest irradiation. Irradiated tadpoles with hind limb-buds from 0.6 mm down to 0.2 mm length were unable to develop normal limbs. This capacity was propontional to the number of non-dividing embryonic cells stored at the time of irradiation. Irradiation of 5000, equal degree but the rapidity was greatest in the cases of higher dosage. Not only did these levels of irradiation fail to destroy the non-dividing embryonic cells but they did not effect their pre-deterrmined specificity nor modify their capacity for subsequent differentiation and growth. Exposure to a thyroxin solution caused the hind limb-buds without visible differentiation of cells to grow from a length of 0.8 or 0.9 mm or 1.0 mm at the time of irradiation to a length of as much as 5.0 mm in the course of 7 days. Development of thigh, shank, ankle, and toes was complete. Microscopic studies showed characteristic tissues such as cartilage, connective tissue, and muscle, developed to a comparable degree in control and irradiated specimens. (auth)« less

Different regulation of limb development by p63 transcript variants.

PubMed

Kawata, Manabu; Taniguchi, Yuki; Mori, Daisuke; Yano, Fumiko; Ohba, Shinsuke; Chung, Ung-Il; Shimogori, Tomomi; Mills, Alea A; Tanaka, Sakae; Saito, Taku

2017-01-01

The apical ectodermal ridge (AER), located at the distal end of each limb bud, is a key signaling center which controls outgrowth and patterning of the proximal-distal axis of the limb through secretion of various molecules. Fibroblast growth factors (FGFs), particularly Fgf8 and Fgf4, are representative molecules produced by AER cells, and essential to maintain the AER and cell proliferation in the underlying mesenchyme, meanwhile Jag2-Notch pathway negatively regulates the AER and limb development. p63, a transcription factor of the p53 family, is expressed in the AER and indispensable for limb formation. However, the underlying mechanisms and specific roles of p63 variants are unknown. Here, we quantified the expression of p63 variants in mouse limbs from embryonic day (E) 10.5 to E12.5, and found that ΔNp63γ was strongly expressed in limbs at all stages, while TAp63γ expression was rapidly increased in the later stages. Fluorescence-activated cell sorting analysis of limb bud cells from reporter mouse embryos at E11.5 revealed that all variants were abundantly expressed in AER cells, and their expression was very low in mesenchymal cells. We then generated AER-specific p63 knockout mice by mating mice with a null and a flox allele of p63, and Msx2-Cre mice (Msx2-Cre;p63Δ/fl). Msx2-Cre;p63Δ/fl neonates showed limb malformation that was more obvious in distal elements. Expression of various AER-related genes was decreased in Msx2-Cre;p63Δ/fl limb buds and embryoid bodies formed by p63-knockdown induced pluripotent stem cells. Promoter analyses and chromatin immunoprecipitation assays demonstrated Fgf8 and Fgf4 as transcriptional targets of ΔNp63γ, and Jag2 as that of TAp63γ. Furthermore, TAp63γ overexpression exacerbated the phenotype of Msx2-Cre;p63Δ/fl mice. These data indicate that ΔNp63 and TAp63 control limb development through transcriptional regulation of different target molecules with different roles in the AER. Our findings contribute to further understanding of the molecular network of limb development.

Identification of a spatially specific enhancer element in the chicken Msx-2 gene that regulates its expression in the apical ectodermal ridge of the developing limb buds of transgenic mice.

PubMed

Sumoy, L; Wang, C K; Lichtler, A C; Pierro, L J; Kosher, R A; Upholt, W B

1995-07-01

Msx-2 is a member of the Msx family of homeobox-containing genes expressed in a variety of embryonic tissues involved in epithelial-mesenchymal interactions and pattern formation. In the developing chick limb bud, Msx-2 is expressed in the apical ectodermal ridge, which plays a crucial role in directing the growth and patterning of limb mesoderm. In addition, Msx-2 is expressed in the anterior nonskeletal-forming mesoderm of the limb bud, in the posterior necrotic zone, and in the interdigital mesenchyme. Studies of the altered expression patterns of Msx-2 in amelic and polydactylous mutant chick limbs have suggested that the apical ectodermal ridge and mesodermal domains of Msx-2 expression are independently regulated and that there might be separate cis-regulatory elements in the Msx-2 gene controlling its spatially distinct domains of expression. To test this hypothesis, we have isolated the chicken Msx-2 gene and have tested the ability of various regions of the gene to target expression of LacZ reporter gene to specific regions of the limbs of transgenic mice. A variety of these constructs are consistently expressed only in the apical ectodermal ridge and the ectoderm of the genital tubercle and are not expressed in the mesoderm of the limb bud or in other regions of the embryo where the endogenous Msx-2 gene is expressed. These results suggest the presence of spatially specific cis-regulatory elements in the Msx-2 gene. We identified a 348-bp region in the 5' flanking region of the Msx-2 gene which can act as an apical ectodermal ridge enhancer element when placed in reverse orientation in front of the reporter gene with transcription initiation directed by the minimal hsp68 promoter.

The flipflop orphan genes are required for limb bud eversion in the Tribolium embryo.

PubMed

Thümecke, Susanne; Beermann, Anke; Klingler, Martin; Schröder, Reinhard

2017-01-01

Unlike Drosophila but similar to other arthropod and vertebrate embryos, the flour beetle Tribolium castaneum develops everted limb buds during embryogenesis. However, the molecular processes directing the evagination of epithelia are only poorly understood. Here we show that the newly discovered genes Tc-flipflop1 and Tc-flipflop2 are involved in regulating the directional budding of appendages. RNAi-knockdown of Tc-flipflop results in a variety of phenotypic traits. Most prominently, embryonic limb buds frequently grow inwards rather than out, leading to the development of inverted appendages inside the larval body. Moreover, affected embryos display dorsal closure defects. The Tc-flipflop genes are evolutionarily non-conserved, and their molecular function is not evident. We further found that Tc-RhoGEF2 , a highly-conserved gene known to be involved in actomyosin-dependent cell movement and cell shape changes, shows a Tc-flipflop -like RNAi-phenotype. The similarity of the inverted appendage phenotype in both the flipflop - and the RhoGEF2 RNAi gene knockdown led us to conclude that the Tc-flipflop orphan genes act in a Rho-dependent pathway that is essential for the early morphogenesis of polarised epithelial movements. Our work describes one of the few examples of an orphan gene playing a crucial role in an important developmental process.

Control of Chondrogenesis in Limb-Bud Cell Cultures by Bromodeoxyuridine

PubMed Central

Levitt, Daniel; Doreman, Albert

1973-01-01

Initial exposure of cultured limb-bud cells (stage 23-24) to 5-bromo-2′-deoxyuridine (BrdU) irreversibly inhibits differentiation to cartilage under three different culture conditions. The inhibition of chondroitin sulfate synthesis is partially reversed by D-xylose in limb-bud cells after treatment with BrdU. The activities of four enzymes involved in chondroitin sulfate production were reduced in BrdU-treated cultures, but the magnitude of decrease was far less than the decrease in glycosaminoglycan synthesis. The slight increase in the turnover rate of sulfated glycosaminoglycans in BrdU-treated mesenchyme was not sufficient to account for the marked decrease in chondroitin sulfate content. The results suggest that BrdU treatment interferes with normal synthesis of chondroitin sulfate core protein in cultured limb-bud cells, but does not greatly diminish enzyme activities or UDP-sugar levels necessary for production of polysaccharide chains. PMID:4275762

A small population of resident limb bud mesenchymal cells express few MSC-associated markers, but the expression of these markers is increased immediately after cell culture.

PubMed

Marín-Llera, Jessica Cristina; Chimal-Monroy, Jesús

2018-05-01

Skeletal progenitors are derived from resident limb bud mesenchymal cells of the vertebrate embryos. However, it remains poorly understood if they represent stem cells, progenitors, or multipotent mesenchymal stromal cells (MSC). Derived-MSC of different adult tissues under in vitro experimental conditions can differentiate into the same cellular lineages that are present in the limb. Here, comparing non-cultured versus cultured mesenchymal limb bud cells, we determined the expression of MSC-associated markers, the in vitro differentiation capacity and their gene expression profile. Results showed that in freshly isolated limb bud mesenchymal cells, the proportion of cells expressing Sca1, CD44, CD105, CD90, and CD73 is very low and a low expression of lineage-specific genes was observed. However, recently seeded limb bud mesenchymal cells acquired Sca1 and CD44 markers and the expression of the key differentiation genes Runx2 and Sox9, while Scx and Pparg genes decreased. Also, their chondrogenic differentiation capacity decreased through cellular passages while the osteogenic increased. Our findings suggest that the modification of the cell adhesion process through the in vitro method changed the limb mesenchymal cell immunophenotype leading to the expression and maintenance of common MSC-associated markers. These findings could have a significant impact on MSC study and isolation strategy because they could explain common variations observed in the MSC immunophenotype in different tissues. © 2018 International Federation for Cell Biology.

Phosphorylation of Lbx1 controls lateral myoblast migration into the limb.

PubMed

Masselink, Wouter; Masaki, Megumi; Sieiro, Daniel; Marcelle, Christophe; Currie, Peter D

2017-10-15

The migration of limb myogenic precursors from limb level somites to their ultimate site of differentiation in the limb is a paradigmatic example of a set of dynamic and orchestrated migratory cell behaviours. The homeobox containing transcription factor ladybird homeobox 1 (Lbx1) is a central regulator of limb myoblast migration, null mutations of Lbx1 result in severe disruptions to limb muscle formation, particularly in the distal region of the limb in mice (Gross et al., 2000). As such Lbx1 has been hypothesized to control lateral migration of myoblasts into the distal limb anlage. It acts as a core regulator of the limb myoblast migration machinery, controlled by Pax3. A secondary role for Lbx1 in the differentiation and commitment of limb musculature has also been proposed (Brohmann et al., 2000; Uchiyama et al., 2000). Here we show that lateral migration, but not differentiation or commitment of limb myoblasts, is controlled by the phosphorylation of three adjacent serine residues of LBX1. Electroporation of limb level somites in the chick embryo with a dephosphomimetic form of Lbx1 results in a specific defect in the lateral migration of limb myoblasts. Although the initial delamination and migration of myoblasts is unaffected, migration into the distal limb bud is severely disrupted. Interestingly, myoblasts undergo normal differentiation independent of their migratory status, suggesting that the differentiation potential of hypaxial muscle is not regulated by the phosphorylation state of LBX1. Furthermore, we show that FGF8 and ERK mediated signal transduction, both critical regulators of the developing limb bud, have the capacity to induce the phosphorylation of LBX1 at these residues. Overall, this suggests a mechanism whereby the phosphorylation of LBX1, potentially through FGF8 and ERK signalling, controls the lateral migration of myoblasts into the distal limb bud. Copyright © 2017. Published by Elsevier Inc.

Evolution of antero‐posterior patterning of the limb: Insights from the chick

PubMed Central

2017-01-01

Summary The developing limbs of chicken embryos have served as pioneering models for understanding pattern formation for over a century. The ease with which chick wing and leg buds can be experimentally manipulated, while the embryo is still in the egg, has resulted in the discovery of important developmental organisers, and subsequently, the signals that they produce. Sonic hedgehog (Shh) is produced by mesenchyme cells of the polarizing region at the posterior margin of the limb bud and specifies positional values across the antero‐posterior axis (the axis running from the thumb to the little finger). Detailed experimental embryology has revealed the fundamental parameters required to specify antero‐posterior positional values in response to Shh signaling in chick wing and leg buds. In this review, the evolution of the avian wing and leg will be discussed in the broad context of tetrapod paleontology, and more specifically, ancestral theropod dinosaur paleontology. How the parameters that dictate antero‐posterior patterning could have been modulated to produce the avian wing and leg digit patterns will be considered. Finally, broader speculations will be made regarding what the antero‐posterior patterning of chick limbs can tell us about the evolution of other digit patterns, including those that were found in the limbs of the earliest tetrapods. PMID:28734068

Chorio-Allantoic Membrane Grafting of Chick Limb Buds as a Class Practical.

ERIC Educational Resources Information Center

McLachlan, John C.

1981-01-01

A new method of carrying out grafts of early embryonic chick limb buds to the chick chorio-allantoic membrane and a processing schedule which renders cartilage elements visible in whole mount are discussed, including implications for the procedures and their results. (Author/DC)

Sall4-Gli3 system in early limb progenitors is essential for the development of limb skeletal elements.

PubMed

Akiyama, Ryutaro; Kawakami, Hiroko; Wong, Julia; Oishi, Isao; Nishinakamura, Ryuichi; Kawakami, Yasuhiko

2015-04-21

Limb skeletal elements originate from the limb progenitor cells, which undergo expansion and patterning to develop each skeletal element. Posterior-distal skeletal elements, such as the ulna/fibula and posterior digits develop in a Sonic hedgehog (Shh)-dependent manner. However, it is poorly understood how anterior-proximal elements, such as the humerus/femur, the radius/tibia and the anterior digits, are developed. Here we show that the zinc finger factors Sall4 and Gli3 cooperate for proper development of the anterior-proximal skeletal elements and also function upstream of Shh-dependent posterior skeletal element development. Conditional inactivation of Sall4 in the mesoderm before limb outgrowth caused severe defects in the anterior-proximal skeletal elements in the hindlimb. We found that Gli3 expression is reduced in Sall4 mutant hindlimbs, but not in forelimbs. This reduction caused posteriorization of nascent hindlimb buds, which is correlated with a loss of anterior digits. In proximal development, Sall4 integrates Gli3 and the Plzf-Hox system, in addition to proliferative expansion of cells in the mesenchymal core of nascent hindlimb buds. Whereas forelimbs developed normally in Sall4 mutants, further genetic analysis identified that the Sall4-Gli3 system is a common regulator of the early limb progenitor cells in both forelimbs and hindlimbs. The Sall4-Gli3 system also functions upstream of the Shh-expressing ZPA and the Fgf8-expressing AER in fore- and hindlimbs. Therefore, our study identified a critical role of the Sall4-Gli3 system at the early steps of limb development for proper development of the appendicular skeletal elements.

Detailed expression profile of the six Glypicans and their modifying enzyme, Notum during chick limb and feather development.

PubMed

Saad, Kawakeb; Theis, Susanne; Otto, Anthony; Luke, Graham; Patel, Ketan

2017-04-30

The development of vertebrate appendages, especially the limb and feather buds are orchestrated by numerous secreted signalling molecules including Sonic Hedgehog, Bone Morphogenetic Proteins, Fibroblast Growth Factors and Wnts. These proteins coordinate the growth and patterning of ectodermal and mesenchymal cells. The influence of signalling molecules is affected over large distances by their concentration (morphogen activity) but also at local levels by the presence of proteins that either attenuate or promote their activity. Glypicans are cell surface molecules that regulate the activity of the major secreted signalling molecules expressed in the limb and feather bud. Here we investigated the expression of all Glypicans during chick limb and feather development. In addition we profiled the expression of Notum, an enzyme that regulates Glypican activity. We show that five of the six Glypicans and Notum are expressed in a dynamic manner during the development of limbs and feathers. We also investigated the expression of key Glypicans and show that they are controlled by signalling molecules highlighting the presence of feedback loops. Lastly we show that Glypicans and Notum are expressed in a tissue specific manner in adult chicken tissues. Our results strongly suggest that the Glypicans and Notum have many as yet undiscovered roles to play during the development of vertebrate appendages. Copyright © 2017 Elsevier B.V. All rights reserved.

Expression of Msx-2 during development, regeneration, and wound healing in axolotl limbs.

PubMed

Carlson, M R; Bryant, S V; Gardiner, D M

1998-12-15

Msx genes are transcription factors that are expressed during embryogenesis of developing appendages in regions of epithelial-mesenchymal interactions. Various lines of evidence indicate that these genes function to maintain embryonic tissues in an undifferentiated, proliferative state. We have identified the axolotl homolog of Msx-2, and investigated its expression during limb development, limb regeneration, and wound healing. As in limb buds of higher vertebrates, axolotl Msx-2 is expressed in the apical epidermis and mesenchyme; however, its expression domain is more extensive, reflecting the broader region of the apical epidermal cap in amphibians. Msx-2 expression is downregulated at late stages of limb development, but is reexpressed within one hour after limb amputation. Msx-2 is also reexpressed during wound healing, and may be essential in the early stages of initiation of the limb regeneration cascade.

Development of five digits is controlled by a bipartite long-range cis-regulator.

PubMed

Lettice, Laura A; Williamson, Iain; Devenney, Paul S; Kilanowski, Fiona; Dorin, Julia; Hill, Robert E

2014-04-01

Conservation within intergenic DNA often highlights regulatory elements that control gene expression from a long range. How conservation within a single element relates to regulatory information and how internal composition relates to function is unknown. Here, we examine the structural features of the highly conserved ZRS (also called MFCS1) cis-regulator responsible for the spatiotemporal control of Shh in the limb bud. By systematically dissecting the ZRS, both in transgenic assays and within in the endogenous locus, we show that the ZRS is, in effect, composed of two distinct domains of activity: one domain directs spatiotemporal activity but functions predominantly from a short range, whereas a second domain is required to promote long-range activity. We show further that these two domains encode activities that are highly integrated and that the second domain is crucial in promoting the chromosomal conformational changes correlated with gene activity. During limb bud development, these activities encoded by the ZRS are interpreted differently by the fore limbs and the hind limbs; in the absence of the second domain there is no Shh activity in the fore limb, and in the hind limb low levels of Shh lead to a variant digit pattern ranging from two to four digits. Hence, in the embryo, the second domain stabilises the developmental programme providing a buffer for SHH morphogen activity and this ensures that five digits form in both sets of limbs.

Gdf11 is a negative regulator of chondrogenesis and myogenesis in the developing chick limb.

PubMed

Gamer, L W; Cox, K A; Small, C; Rosen, V

2001-01-15

GDF11, a new member of the TGF-beta gene superfamily, regulates anterior/posterior patterning in the axial skeleton during mouse embryogenesis. Gdf11 null mice display skeletal abnormalities that appear to represent anterior homeotic transformations of vertebrae consistent with high levels of Gdf11 expression in the primitive streak, presomitic mesoderm, and tail bud. However, despite strong Gdf11 expression in the limb throughout development, this structure does not appear to be affected in the knockout mice. In order to understand this dichotomy of Gdf11 expression versus Gdf11 function, we identified the chicken Gdf11 gene and studied its role during limb formation. In the early limb bud, Gdf11 transcripts are detected in the subectodermal mesoderm at the distal tip, in a region overlapping the progress zone. At these stages, Gdf11 is excluded from the central core mesenchyme where precartilaginous condensations will form. Later in development, Gdf11 continues to be expressed in the distal most mesenchyme and can also be detected more proximally, in between the forming skeletal elements. When beads incubated in GDF11 protein were implanted into the early wing bud, GDF11 caused severe truncations of the limb that affected both the cartilage elements and the muscle. Limb shortening appeared to be the result of an inhibition of chondrogenesis and myogenesis and using an in vitro micromass assay, we confirmed the negative effects of GDF11 on both myogenic and chondrogenic cell differentiation. Analysis of molecular markers of skeletal patterning revealed that GDF11 induced ectopic expression of Hoxd-11 and Hoxd-13, but not of Hoxa-11, Hoxa-13, or the Msx genes. These data suggest that GDF11 may be involved in controlling the late distal expression of the Hoxd genes during limb development and that misregulation of these Hox genes by excess GDF11 may cause some of the observed alterations in skeletal element shape. In addition, GDF11 induced the expression of its own antagonist follistatin, indicating that the activity of GFD11 may be limited by a negative feedback mechanism. The data from our studies in the chick suggest that Gdf11 plays a role in the formation and development of the avian limb skeleton.

Cellular anomalies underlying retinoid-induced phocomelia.

PubMed

Zhou, Jian; Kochhar, Devendra M

2004-11-01

The question of how alterations in cell behavior produced by retinoic acid (RA) influenced the development of skeletogenic mesenchyme of the limb bud was examined in this study. Our established model was employed, which involves treatment of pregnant mice with a teratogenic dose of RA (100 mg/kg) on 11 days postcoitum (dpc) resulting in a severe truncation of all long bones of the forelimbs in virtually every exposed fetus. It is shown that RA, administered at a stage to induce phocomelia in virtually all exposed embryos, resulted in immediate appearance of enhanced cell death within the mesenchyme in the central core of the limb bud, an area destined for chondrogenesis. The central core mesenchyme, which in the untreated limb buds experiences a sharp decline in cell proliferation heralding the onset of chondrogenesis, demonstrated a reversal of the process; this mesenchyme maintained a higher rate of cell proliferation upon RA exposure. These events resulted in a truncation and disorganization of the chondrogenic anlage, more pronounced in zeugopodal mesenchyme than in the autopod. We conclude that an inhibition of chondrogenesis was secondary to a disruption in cellular behavior caused by RA, a likely consequence of misregulation in the growth factor signaling cascade.

Development of five digits is controlled by a bipartite long-range cis-regulator

PubMed Central

Lettice, Laura A.; Williamson, Iain; Devenney, Paul S.; Kilanowski, Fiona; Dorin, Julia; Hill, Robert E.

2014-01-01

Conservation within intergenic DNA often highlights regulatory elements that control gene expression from a long range. How conservation within a single element relates to regulatory information and how internal composition relates to function is unknown. Here, we examine the structural features of the highly conserved ZRS (also called MFCS1) cis-regulator responsible for the spatiotemporal control of Shh in the limb bud. By systematically dissecting the ZRS, both in transgenic assays and within in the endogenous locus, we show that the ZRS is, in effect, composed of two distinct domains of activity: one domain directs spatiotemporal activity but functions predominantly from a short range, whereas a second domain is required to promote long-range activity. We show further that these two domains encode activities that are highly integrated and that the second domain is crucial in promoting the chromosomal conformational changes correlated with gene activity. During limb bud development, these activities encoded by the ZRS are interpreted differently by the fore limbs and the hind limbs; in the absence of the second domain there is no Shh activity in the fore limb, and in the hind limb low levels of Shh lead to a variant digit pattern ranging from two to four digits. Hence, in the embryo, the second domain stabilises the developmental programme providing a buffer for SHH morphogen activity and this ensures that five digits form in both sets of limbs. PMID:24715461

Suppression of morphogenesis in embryonic mouse limbs exposed in vitro to excess gravity.

PubMed

Duke, J C

1983-06-01

This paper is a report of the first investigation of the effect of excess gravity on in vitro mammalian limb chondrogenesis. Limb buds from mice of various gestational stages were exposed to excess gravity (2.6G) using a culture centrifuge. Both forelimbs and hind limbs were cultured and the development of various limb elements was scored after four to six days. The 2.6G force significantly depressed the development of limb elements when applied during the teratogen-sensitive period of chondrogenesis. There was a proximodistal gradient of sensitivity to excess gravity in the limb with proximal structures being less susceptible than distal ones. In some cases, proximal limb elements present prior to explantation disappeared upon exposure to excess gravity. Hypergravity's teratogenic effect is assumed to operate via changes in tension and/or pressure on the cells, accompanied by alterations in cell morphometry and membrane properties.

Heterochronic shift in Hox-mediated activation of sonic hedgehog leads to morphological changes during fin development.

PubMed

Sakamoto, Koji; Onimaru, Koh; Munakata, Keijiro; Suda, Natsuno; Tamura, Mika; Ochi, Haruki; Tanaka, Mikiko

2009-01-01

We explored the molecular mechanisms of morphological transformations of vertebrate paired fin/limb evolution by comparative gene expression profiling and functional analyses. In this study, we focused on the temporal differences of the onset of Sonic hedgehog (Shh) expression in paired appendages among different vertebrates. In limb buds of chick and mouse, Shh expression is activated as soon as there is a morphological bud, concomitant with Hoxd10 expression. In dogfish (Scyliorhinus canicula), however, we found that Shh was transcribed late in fin development, concomitant with Hoxd13 expression. We utilized zebrafish as a model to determine whether quantitative changes in hox expression alter the timing of shh expression in pectoral fins of zebrafish embryos. We found that the temporal shift of Shh activity altered the size of endoskeletal elements in paired fins of zebrafish and dogfish. Thus, a threshold level of hox expression determines the onset of shh expression, and the subsequent heterochronic shift of Shh activity can affect the size of the fin endoskeleton. This process may have facilitated major morphological changes in paired appendages during vertebrate limb evolution.

Ectopic expression of Msx-2 in posterior limb bud mesoderm impairs limb morphogenesis while inducing BMP-4 expression, inhibiting cell proliferation, and promoting apoptosis.

PubMed

Ferrari, D; Lichtler, A C; Pan, Z Z; Dealy, C N; Upholt, W B; Kosher, R A

1998-05-01

During early stages of chick limb development, the homeobox-containing gene Msx-2 is expressed in the mesoderm at the anterior margin of the limb bud and in a discrete group of mesodermal cells at the midproximal posterior margin. These domains of Msx-2 expression roughly demarcate the anterior and posterior boundaries of the progress zone, the highly proliferating posterior mesodermal cells underneath the apical ectodermal ridge (AER) that give rise to the skeletal elements of the limb and associated structures. Later in development as the AER loses its activity, Msx-2 expression expands into the distal mesoderm and subsequently into the interdigital mesenchyme which demarcates the developing digits. The domains of Msx-2 expression exhibit considerably less proliferation than the cells of the progress zone and also encompass several regions of programmed cell death including the anterior and posterior necrotic zones and interdigital mesenchyme. We have thus suggested that Msx-2 may be in a regulatory network that delimits the progress zone by suppressing the morphogenesis of the regions of the limb mesoderm in which it is highly expressed. In the present study we show that ectopic expression of Msx-2 via a retroviral expression vector in the posterior mesoderm of the progress zone from the time of initial formation of the limb bud severely impairs limb morphogenesis. Msx-2-infected limbs are typically very narrow along the anteroposterior axis, are occasionally truncated, and exhibit alterations in the pattern of formation of skeletal elements, indicating that as a consequence of ectopic Msx-2 expression the morphogenesis of large portions of the posterior mesoderm has been suppressed. We further show that Msx-2 impairs limb morphogenesis by reducing cell proliferation and promoting apoptosis in the regions of the posterior mesoderm in which it is ectopically expressed. The domains of ectopic Msx-2 expression in the posterior mesoderm also exhibit ectopic expression of BMP-4, a secreted signaling molecule that is coexpressed with Msx-2 during normal limb development in the anterior limb mesoderm, the posterior necrotic zone, and interdigital mesenchyme. This indicates that Msx-2 regulates BMP-4 expression and that the suppressive effects of Msx-2 on limb morphogenesis might be mediated in part by BMP-4. These studies indicate that during normal limb development Msx-2 is a key component of a regulatory network that delimits the boundaries of the progress zone by suppressing the morphogenesis of the regions of the limb mesoderm in which it is highly expressed, thus restricting the outgrowth and formation of skeletal elements and associated structures to the progress zone. We also report that rather large numbers of apoptotic cells as well as proliferating cells are present throughout the AER during all stages of normal limb development we have examined, indicating that many of the cells of the AER are continuously undergoing programmed cell death at the same time that new AER cells are being generated by cell proliferation. Thus, a balance between cell proliferation and programmed cell death may play a very important role in maintaining the activity of the AER. Copyright 1998 Academic Press.

Opposing Functions of the ETS Factor Family Define Shh Spatial Expression in Limb Buds and Underlie Polydactyly

PubMed Central

Lettice, Laura A.; Williamson, Iain; Wiltshire, John H.; Peluso, Silvia; Devenney, Paul S.; Hill, Alison E.; Essafi, Abdelkader; Hagman, James; Mort, Richard; Grimes, Graeme; DeAngelis, Carlo L.; Hill, Robert E.

2012-01-01

Summary Sonic hedgehog (Shh) expression during limb development is crucial for specifying the identity and number of digits. The spatial pattern of Shh expression is restricted to a region called the zone of polarizing activity (ZPA), and this expression is controlled from a long distance by the cis-regulator ZRS. Here, members of two groups of ETS transcription factors are shown to act directly at the ZRS mediating a differential effect on Shh, defining its spatial expression pattern. Occupancy at multiple GABPα/ETS1 sites regulates the position of the ZPA boundary, whereas ETV4/ETV5 binding restricts expression outside the ZPA. The ETS gene family is therefore attributed with specifying the boundaries of the classical ZPA. Two point mutations within the ZRS change the profile of ETS binding and activate Shh expression at an ectopic site in the limb bud. These molecular changes define a pathogenetic mechanism that leads to preaxial polydactyly (PPD). PMID:22340503

Developmental origin of limb size variation in lizards.

PubMed

Andrews, Robin M; Skewes, Sable A

2017-05-01

In many respects, reptile hatchlings are fully functional, albeit miniature, adults. This means that the adult morphology must emerge during embryonic development. This insight emphasizes the connection between the mechanisms that generate phenotypic variation during embryonic development and the action of selection on post-hatching individuals. To determine when species-specific differences in limb and tail lengths emerge during embryonic development, we compared allometric patterns of early limb growth of four distantly related species of lizards. The major questions addressed were whether early embryonic limb and tail growth is characterized by the gradual (continuous allometry) or by the abrupt emergence (transpositional allometry) of size differences among species. Our observations supported transpositional allometry of both limbs and tails. Species-specific differences in limb and tail length were exhibited when limb and tail buds first protruded from the body wall. Genes known to be associated with early limb development of tetrapods are obvious targets for studies on the genetic mechanisms that determine interspecific differences in relative limb length. Broadly comparative studies of gene regulation would facilitate understanding of the mechanisms underlying adaptive variation in limb size, including limb reduction and loss, of squamate reptiles. © 2017 Wiley Periodicals, Inc.

Vertebrate limb development: moving from classical morphogen gradients to an integrated 4-dimensional patterning system.

PubMed

Bénazet, Jean-Denis; Zeller, Rolf

2009-10-01

A wealth of classical embryological manipulation experiments taking mainly advantage of the chicken limb buds identified the apical ectodermal ridge (AER) and the zone of polarizing activity (ZPA) as the respective ectodermal and mesenchymal key signaling centers coordinating proximodistal (PD) and anteroposterior (AP) limb axis development. These experiments inspired Wolpert's French flag model, which is a classic among morphogen gradient models. Subsequent molecular and genetic analysis in the mouse identified retinoic acid as proximal signal, and fibroblast growth factors (FGFs) and sonic hedgehog (SHH) as the essential instructive signals produced by AER and ZPA, respectively. Recent studies provide good evidence that progenitors are specified early with respect to their PD and AP fates and that morpho-regulatory signaling is also required for subsequent proliferative expansion of the specified progenitor pools. The determination of particular fates seems to occur rather late and depends on additional signals such as bone morphogenetic proteins (BMPs), which indicates that cells integrate signaling inputs over time and space. The coordinate regulation of PD and AP axis patterning is controlled by an epithelial-mesenchymal feedback signaling system, in which transcriptional regulation of the BMP antagonist Gremlin1 integrates inputs from the BMP, SHH, and FGF pathways. Vertebrate limb-bud development is controlled by a 4-dimensional (4D) patterning system integrating positive and negative regulatory feedback loops, rather than thresholds set by morphogen gradients.

Multi-view light-sheet imaging and tracking with the MaMuT software reveals the cell lineage of a direct developing arthropod limb

PubMed Central

Stamataki, Evangelia; Harich, Benjamin; Guignard, Léo; Preibisch, Stephan; Shorte, Spencer; Keller, Philipp J

2018-01-01

During development, coordinated cell behaviors orchestrate tissue and organ morphogenesis. Detailed descriptions of cell lineages and behaviors provide a powerful framework to elucidate the mechanisms of morphogenesis. To study the cellular basis of limb development, we imaged transgenic fluorescently-labeled embryos from the crustacean Parhyale hawaiensis with multi-view light-sheet microscopy at high spatiotemporal resolution over several days of embryogenesis. The cell lineage of outgrowing thoracic limbs was reconstructed at single-cell resolution with new software called Massive Multi-view Tracker (MaMuT). In silico clonal analyses suggested that the early limb primordium becomes subdivided into anterior-posterior and dorsal-ventral compartments whose boundaries intersect at the distal tip of the growing limb. Limb-bud formation is associated with spatial modulation of cell proliferation, while limb elongation is also driven by preferential orientation of cell divisions along the proximal-distal growth axis. Cellular reconstructions were predictive of the expression patterns of limb development genes including the BMP morphogen Decapentaplegic. PMID:29595475

Expression of Wise in chick embryos.

PubMed

Shigetani, Y; Itasaki, N

2007-08-01

We have performed in situ hybridization to study the expression of Wise in early chick embryos. Wise expression is first detectable in the ectoderm at posterior levels of late neurula. As development proceeds, Wise expression is seen in specific patterns in the ectoderm of the trunk region, pharyngeal arches, limb buds, and feather buds. In addition to these areas, particular cartilages such as the ones in the maxillary process and limbs start to express Wise at the late pharyngula stage, and the expression in these cartilages becomes stronger than that in epidermal components at later stages. Importantly, Wise is expressed in regions where other signaling molecules such as Wnt, Bmp, and Shh are known to function in morphogenesis and differentiation. Direct comparisons of the expression of Wise and these genes are also demonstrated. (c) 2007 Wiley-Liss, Inc.

Growth and differentiation of mammalian embryonic tissues exposed to hypergravity in vivo and in vitro

NASA Technical Reports Server (NTRS)

Duke, J.; Janer, L.; Moore, J.

1985-01-01

Decreased cartilage areas in embryonic limbs developing under excess g in vitro, is reported, as well as delayed skeletal development in embryos and fetuses exposed to excess g in utero. 12.5-day mouse limb buds were cultured at 2.6 g, and fixed at two days and six days of culture. In vivo experiments used alizarin-stained 18-day fetuses exposed to 2.3 g. In all studies, cartilage areas were determined using a digitized tablet. Form factor analysis determined that the main effect of in vitro centrifugation was a reduction in length of the limb elements, probably due to the precocious chondrogenesis seen in the upper regions of centrifuged limbs. Similar reductions in length of ossified areas was seen in the in utero studies.

Dynamic gene expression of Lin-28 during embryonic development in mouse and chicken.

PubMed

Yokoyama, Shigetoshi; Hashimoto, Megumi; Shimizu, Hirohito; Ueno-Kudoh, Hiroe; Uchibe, Kenta; Kimura, Ichiro; Asahara, Hiroshi

2008-02-01

The Caenorhabditis elegans heterochronic gene lin-28 regulates developmental timing in the nematode trunk. We report the dynamic expression patterns of Lin-28 homologues in mouse and chick embryos. Whole mount in situ hybridization revealed specific and intriguing expression patterns of Lin-28 in the developing mouse and chick limb bud. Mouse Lin-28 expression was detected in both the forelimb and hindlimb at E9.5, but disappeared from the forelimb at E10.5, and finally from the forelimb and hindlimb at E11.5. Chicken Lin-28, which was first detected in the limb primordium at stage 15/16, was also downregulated as the stage proceeded. The amino acid sequences of mouse and chicken Lin-28 genes are highly conserved and the similar expression patterns of Lin-28 during limb development in mouse and chicken suggest that this heterochronic gene is also conserved during vertebrate limb development.

PRMT5 is essential for the maintenance of chondrogenic progenitor cells in the limb bud

PubMed Central

Norrie, Jacqueline L.; Li, Qiang; Co, Swanie; Huang, Bau-Lin; Ding, Ding; Uy, Jann C.; Ji, Zhicheng; Mackem, Susan; Bedford, Mark T.; Galli, Antonella; Ji, Hongkai

2016-01-01

During embryonic development, undifferentiated progenitor cells balance the generation of additional progenitor cells with differentiation. Within the developing limb, cartilage cells differentiate from mesodermal progenitors in an ordered process that results in the specification of the correct number of appropriately sized skeletal elements. The internal pathways by which these cells maintain an undifferentiated state while preserving their capacity to differentiate is unknown. Here, we report that the arginine methyltransferase PRMT5 has a crucial role in maintaining progenitor cells. Mouse embryonic buds lacking PRMT5 have severely truncated bones with wispy digits lacking joints. This novel phenotype is caused by widespread cell death that includes mesodermal progenitor cells that have begun to precociously differentiate into cartilage cells. We propose that PRMT5 maintains progenitor cells through its regulation of Bmp4. Intriguingly, adult and embryonic stem cells also require PRMT5 for maintaining pluripotency, suggesting that similar mechanisms might regulate lineage-restricted progenitor cells during organogenesis. PMID:27827819

PRMT5 is essential for the maintenance of chondrogenic progenitor cells in the limb bud.

PubMed

Norrie, Jacqueline L; Li, Qiang; Co, Swanie; Huang, Bau-Lin; Ding, Ding; Uy, Jann C; Ji, Zhicheng; Mackem, Susan; Bedford, Mark T; Galli, Antonella; Ji, Hongkai; Vokes, Steven A

2016-12-15

During embryonic development, undifferentiated progenitor cells balance the generation of additional progenitor cells with differentiation. Within the developing limb, cartilage cells differentiate from mesodermal progenitors in an ordered process that results in the specification of the correct number of appropriately sized skeletal elements. The internal pathways by which these cells maintain an undifferentiated state while preserving their capacity to differentiate is unknown. Here, we report that the arginine methyltransferase PRMT5 has a crucial role in maintaining progenitor cells. Mouse embryonic buds lacking PRMT5 have severely truncated bones with wispy digits lacking joints. This novel phenotype is caused by widespread cell death that includes mesodermal progenitor cells that have begun to precociously differentiate into cartilage cells. We propose that PRMT5 maintains progenitor cells through its regulation of Bmp4 Intriguingly, adult and embryonic stem cells also require PRMT5 for maintaining pluripotency, suggesting that similar mechanisms might regulate lineage-restricted progenitor cells during organogenesis. © 2016. Published by The Company of Biologists Ltd.

A Heart-Hand Syndrome Gene: Tfap2b Plays a Critical Role in the Development and Remodeling of Mouse Ductus Arteriosus and Limb Patterning

PubMed Central

Zhao, Feng; Bosserhoff, Anja-Katrin; Buettner, Reinhard; Moser, Markus

2011-01-01

Background Patent ductus arteriosus (PDA) is one of the most common forms of congenital heart disease. Mutations in transcription factor TFAP2B cause Char syndrome, a human disorder characterized by PDA, facial dysmorphysm and hand anomalies. Animal research data are needed to understand the mechanisms. The aim of our study was to elucidate the pathogenesis of Char syndrome at the molecular level. Methodology/Principal Findings Gene expression of Tfap2b during mouse development was studied, and newborns of Tfap2b-deficient mice were examined to identify phenotypes. Gel shift assays had been carried out to search for Tfap2 downstream genes. Promoters of candidate genes were cloned into a reporter construct and used to demonstrate their regulation by Tfap2b in cell transfection. In situ hybridizations showed that the murine transcription factor Tfap2b was expressed during the entire development of mouse ductus arteriosus. Histological examination of ductus arteriosus from Tfap2b knockout mice 6 hours after birth revealed that they were not closed. Consequently, the lungs of Tfap2b −/− mice demonstrated progressive congestion of the pulmonary capillaries, which was postulated to result secondarily from PDA. In addition, Tfap2b was expressed in the limb buds, particularly in the posterior limb field during development. Lack of Tfap2b resulted in bilateral postaxial accessory digits. Further study indicated that expressions of bone morphogenetic protein (Bmp) genes, which are reported to be involved in the limb patterning and ductal development, were altered in limb buds of Tfap2b-deficient embryos, due to direct control of Bmp2 and Bmp4 promoter activity by Tfap2b. Conclusions/Significance Tfap2b plays important roles in the development of mouse ductus arteriosus and limb patterning. Loss of Tfap2b results in altered Bmp expression that may cause the heart-limb defects observed in Tfap2b mouse mutants and Char syndrome patients. The Tfap2b knockout mouse may add to the very limited available animal models of PDA. PMID:21829553

Comparative Transcriptional Profiling of the Axolotl Limb Identifies a Tripartite Regeneration-Specific Gene Program

PubMed Central

Knapp, Dunja; Schulz, Herbert; Rascon, Cynthia Alexander; Volkmer, Michael; Scholz, Juliane; Nacu, Eugen; Le, Mu; Novozhilov, Sergey; Tazaki, Akira; Protze, Stephanie; Jacob, Tina; Hubner, Norbert; Habermann, Bianca; Tanaka, Elly M.

2013-01-01

Understanding how the limb blastema is established after the initial wound healing response is an important aspect of regeneration research. Here we performed parallel expression profile time courses of healing lateral wounds versus amputated limbs in axolotl. This comparison between wound healing and regeneration allowed us to identify amputation-specific genes. By clustering the expression profiles of these samples, we could detect three distinguishable phases of gene expression – early wound healing followed by a transition-phase leading to establishment of the limb development program, which correspond to the three phases of limb regeneration that had been defined by morphological criteria. By focusing on the transition-phase, we identified 93 strictly amputation-associated genes many of which are implicated in oxidative-stress response, chromatin modification, epithelial development or limb development. We further classified the genes based on whether they were or were not significantly expressed in the developing limb bud. The specific localization of 53 selected candidates within the blastema was investigated by in situ hybridization. In summary, we identified a set of genes that are expressed specifically during regeneration and are therefore, likely candidates for the regulation of blastema formation. PMID:23658691

Genetics Home Reference: Miller syndrome

MedlinePlus

... a limb bud, which grows outward. Many different proteins are involved in the normal shaping (patterning) of each limb. Once the overall pattern of a ... for This Page Biesecker LG. Exome sequencing makes medical genomics a reality. Nat Genet. 2010 ...

Heterochrony in the regulation of the developing marsupial limb.

PubMed

Chew, Keng Yih; Shaw, Geoffrey; Yu, Hongshi; Pask, Andrew J; Renfree, Marilyn B

2014-02-01

At birth, marsupial neonates have precociously developed forelimbs. The development of the tammar wallaby (Macropus eugenii) hindlimbs lags significantly behind that of the forelimbs. This differs from the grey short-tailed opossum, Monodelphis domestica, which has relatively similar fore- and hindlimbs at birth. This study examines the expression of the key patterning genes TBX4, TBX5, PITX1, FGF8, and SHH in developing limb buds in the tammar wallaby. All genes examined were highly conserved with orthologues from opossum and mouse. TBX4 expression appeared earlier in development than in the mouse, but later than in the opossum. SHH expression is restricted to the zone of polarising activity, while TBX5 (forelimb) and PITX1 (hindlimb) showed diffuse mRNA expression. FGF8 is specifically localised to the apical ectodermal ridge, which is more prominent than in the opossum. The most marked divergence in limb size in marsupials occurs in the kangaroos and wallabies. The faster development of the fore limb compared to that of the hind limb correlates with the early timing of the expression of the key patterning genes in these limbs. Copyright © 2013 Wiley Periodicals, Inc.

HOXA13 and HOXD13 expression during development of the syndactylous digits in the marsupial Macropus eugenii

PubMed Central

2012-01-01

Background Kangaroos and wallabies have specialised limbs that allow for their hopping mode of locomotion. The hindlimbs differentiate much later in development but become much larger than the forelimbs. The hindlimb autopod has only four digits, the fourth of which is greatly elongated, while digits two and three are syndactylous. We investigated the expression of two genes, HOXA13 and HOXD13, that are crucial for digit patterning in mice during formation of the limbs of the tammar wallaby. Results We describe the development of the tammar limbs at key stages before birth. There was marked heterochrony and the hindlimb developed more slowly than the forelimb. Both tammar HOXA13 and HOXD13 have two exons as in humans, mice and chickens. HOXA13 had an early and distal mRNA distribution in the tammar limb bud as in the mouse, but forelimb expression preceded that in the hindlimb. HOXD13 mRNA was expressed earlier in the forelimb than the hindlimb and was predominantly detected in the interdigital tissues of the forelimb. In contrast, the hindlimb had a more restricted expression pattern that appeared to be expressed at discrete points at both posterior and anterior margins of the limb bud, and was unlike expression seen in the mouse and the chicken. Conclusions This is the first examination of HOXA and HOXD gene expression in a marsupial. The gene structure and predicted proteins were highly conserved with their eutherian orthologues. Interestingly, despite the morphological differences in hindlimb patterning, there were no modifications to the polyalanine tract of either HOXA13 or HOXD13 when compared to those of the mouse and bat but there was a marked difference between the tammar and the other mammals in the region of the first polyserine tract of HOXD13. There were also altered expression domains for both genes in the developing tammar limbs compared to the chicken and mouse. Together these findings suggest that the timing of HOX gene expression may contribute to the heterochrony of the forelimb and hindlimb and that alteration to HOX domains may influence phenotypic differences that lead to the development of marsupial syndactylous digits. PMID:22235805

A relative shift in cloacal location repositions external genitalia in amniote evolution.

PubMed

Tschopp, Patrick; Sherratt, Emma; Sanger, Thomas J; Groner, Anna C; Aspiras, Ariel C; Hu, Jimmy K; Pourquié, Olivier; Gros, Jérôme; Tabin, Clifford J

2014-12-18

The move of vertebrates to a terrestrial lifestyle required major adaptations in their locomotory apparatus and reproductive organs. While the fin-to-limb transition has received considerable attention, little is known about the developmental and evolutionary origins of external genitalia. Similarities in gene expression have been interpreted as a potential evolutionary link between the limb and genitals; however, no underlying developmental mechanism has been identified. We re-examined this question using micro-computed tomography, lineage tracing in three amniote clades, and RNA-sequencing-based transcriptional profiling. Here we show that the developmental origin of external genitalia has shifted through evolution, and in some taxa limbs and genitals share a common primordium. In squamates, the genitalia develop directly from the budding hindlimbs, or the remnants thereof, whereas in mice the genital tubercle originates from the ventral and tail bud mesenchyme. The recruitment of different cell populations for genital outgrowth follows a change in the relative position of the cloaca, the genitalia organizing centre. Ectopic grafting of the cloaca demonstrates the conserved ability of different mesenchymal cells to respond to these genitalia-inducing signals. Our results support a limb-like developmental origin of external genitalia as the ancestral condition. Moreover, they suggest that a change in the relative position of the cloacal signalling centre during evolution has led to an altered developmental route for external genitalia in mammals, while preserving parts of the ancestral limb molecular circuitry owing to a common evolutionary origin.

Transcriptomic insights into the genetic basis of mammalian limb diversity.

PubMed

Maier, Jennifer A; Rivas-Astroza, Marcelo; Deng, Jenny; Dowling, Anna; Oboikovitz, Paige; Cao, Xiaoyi; Behringer, Richard R; Cretekos, Chris J; Rasweiler, John J; Zhong, Sheng; Sears, Karen E

2017-03-23

From bat wings to whale flippers, limb diversification has been crucial to the evolutionary success of mammals. We performed the first transcriptome-wide study of limb development in multiple species to explore the hypothesis that mammalian limb diversification has proceeded through the differential expression of conserved shared genes, rather than by major changes to limb patterning. Specifically, we investigated the manner in which the expression of shared genes has evolved within and among mammalian species. We assembled and compared transcriptomes of bat, mouse, opossum, and pig fore- and hind limbs at the ridge, bud, and paddle stages of development. Results suggest that gene expression patterns exhibit larger variation among species during later than earlier stages of limb development, while within species results are more mixed. Consistent with the former, results also suggest that genes expressed at later developmental stages tend to have a younger evolutionary age than genes expressed at earlier stages. A suite of key limb-patterning genes was identified as being differentially expressed among the homologous limbs of all species. However, only a small subset of shared genes is differentially expressed in the fore- and hind limbs of all examined species. Similarly, a small subset of shared genes is differentially expressed within the fore- and hind limb of a single species and among the forelimbs of different species. Taken together, results of this study do not support the existence of a phylotypic period of limb development ending at chondrogenesis, but do support the hypothesis that the hierarchical nature of development translates into increasing variation among species as development progresses.

Leaping lopsided: a review of the current hypotheses regarding etiologies of limb malformations in frogs.

PubMed

Loeffler, I K; Stocum, D L; Fallon, J F; Meteyer, C U

2001-10-15

Recent progress in the investigation of limb malformations in free-living frogs has underlined the wide range in the types of limb malformations and the apparent spatiotemporal clustering of their occurrence. Here, we review the current understanding of normal and abnormal vertebrate limb development and regeneration and discuss some of the molecular events that may bring about limb malformation. Consideration of the differences between limb development and regeneration in amphibians has led us to the hypothesis that some of the observed limb malformations come about through misdirected regeneration. We report the results of a pilot study that supports this hypothesis. In this study, the distal aspect of the right hindlimb buds of X. laevis tadpoles was amputated at the pre-foot paddle stage. The tadpoles were raised in water from a pond in Minnesota at which 7% of surveyed newly metamorphosed feral frogs had malformations. Six percent (6 of 100) of the right limbs of the tadpoles raised in pond water developed abnormally. One truncated right limb was the only malformation in the control group, which was raised in dechlorinated municipal water. All unamputated limbs developed normally in both groups. Three major factors under consideration for effecting the limb malformations are discussed. These factors include environmental chemicals (primarily agrichemicals), encysted larvae (metacercariae) of trematode parasites, and increased levels of ultraviolet light. Emphasis is placed on the necessary intersection of environmental stressors and developmental events to bring about the specific malformations that are observed in free-living frog populations.

Leaping lopsided: a review of the current hypotheses regarding etiologies of limb malformations in frogs

USGS Publications Warehouse

Loeffler, I.K.; Stocum, D.L.; Fallon, J.F.; Meteyer, C.U.

2001-01-01

Recent progress in the investigation of limb malformations in free-living frogs has underlined the wide range in the types of limb malformations and the apparent spatiotemporal clustering of their occurrence. Here, we review the current understanding of normal and abnormal vertebrate limb development and regeneration and discuss some of the molecular events that may bring about limb malformation. Consideration of the differences between limb development and regeneration in amphibians has led us to the hypothesis that some of the observed limb malformations come about through misdirected regeneration. We report the results of a pilot study that supports this hypothesis. In this study, the distal aspect of the right hindlimb buds of X. laevis tadpoles was amputated at the pre-foot paddle stage. The tadpoles were raised in water from a pond in Minnesota at which 7% of surveyed newly metamorphosed feral frogs had malformations. Six percent (6 of 100) of the right limbs of the tadpoles raised in pond water developed abnormally. One truncated right limb was the only malformation in the control group, which was raised in dechlorinated municipal water. All unamputated limbs developed normally in both groups. Three major factors under consideration for effecting the limb malformations are discussed. These factors include environmental chemicals (primarily agrichemicals), encysted larvae (metacercariae) of trematode parasites, and increased levels of ultraviolet light. Emphasis is placed on the necessary intersection of environmental stressors and developmental events to bring about the specific malformations that are observed in free-living frog populations.

Watch-ing out for chick limb development.

PubMed

Pascoal, Susana; Palmeirim, Isabel

2007-09-01

Time control is a crucial issue during embryonic development. Nevertheless, little is known about how embryonic cells measure time. Until recently, the only molecular clock known to operate during vertebrate embryonic development was the somitogenesis clock, exclusively functioning in coordinating the precise timing of each new pair of somites formed from the presomitic mesoderm. We have recently evidenced that a similar molecular clock also underlies the timing at which autopod chondrogenic precursors are laid down to form a skeletal limb element. In addition, we herein suggest that the molecular clock is not the only parallelism that can be established between somitogenesis and limb-bud development. In an evolutionary perspective, we support the previously proposed idea that the molecular mechanisms involved in the segmentation of the body axis may have been partially reused in the mesoderm of the lateral plate, thereby allowing the emergence of paired appendages.

Attenuation of bone morphogenetic protein signaling during amphibian limb development results in the generation of stage-specific defects.

PubMed

Jones, Tamsin E M; Day, Robert C; Beck, Caroline W

2013-11-01

The vertebrate limb is one of the most intensively studied organs in the field of developmental biology. Limb development in tetrapod vertebrates is highly conserved and dependent on the interaction of several important molecular pathways. The bone morphogenetic protein (BMP) signaling cascade is one of these pathways and has been shown to be crucial for several aspects of limb development. Here, we have used a Xenopus laevis transgenic line, in which expression of the inhibitor Noggin is under the control of the heat-shock promoter hsp70 to examine the effects of attenuation of BMP signaling at different stages of limb development. Remarkably different phenotypes were produced at different stages, illustrating the varied roles of BMP in development of the limb. Very early limb buds appeared to be refractory to the effects of BMP attenuation, developing normally in most cases. Ectopic limbs were produced by overexpression of Noggin corresponding to a brief window of limb development at about stage 49/50, as recently described by Christen et al. (2012). Attenuation of BMP signaling in stage 51 or 52 tadpoles lead to a reduction in the number of digits formed, resulting in hypodactyly or ectrodactyly, as well as occasional defects in the more proximal tibia-fibula. Finally, inhibition at stage 54 (paddle stage) led to the formation of dramatically shortened digits resulting from loss of distal phalanges. Transcriptome analysis has revealed the possibility that more Noggin-sensitive members of the BMP family could be involved in limb development than previously suspected. Our analysis demonstrates the usefulness of heat-shock-driven gene expression as an effective method for inhibiting a developmental pathway at different times during limb development. © 2013 Anatomical Society.

Curcumin inhibits cellular condensation and alters microfilament organization during chondrogenic differentiation of limb bud mesenchymal cells.

PubMed

Kim, Dong Kyun; Kim, Song Ja; Kang, Shin Sung; Jin, Eun Jung

2009-09-30

Curcumin is a well known natural polyphenol product isolated from the rhizome of the plant Curcuma longa, anti-inflammatory agent for arthritis by inhibiting synthesis of inflammatory prostaglandins. However, the mechanisms by which curcumin regulates the functions of chondroprogenitor, such as proliferation, precartilage condensation, cytoskeletal organization or overall chondrogenic behavior, are largely unknown. In the present report, we investigated the effects and signaling mechanism of curcumin on the regulation of chondrogenesis. Treating chick limb bud mesenchymal cells with curcumin suppressed chondrogenesis by stimulating apoptotic cell death. It also inhibited reorganization of the actin cytoskeleton into a cortical pattern concomitant with rounding of chondrogenic competent cells and down-regulation of integrin beta1 and focal adhesion kinase (FAK) phosphorylation. Curcumin suppressed the phosphorylation of Akt leading to Akt inactivation. Activation of Akt by introducing a myristoylated, constitutively active form of Akt reversed the inhibitory actions of curcumin during chondrogenesis. In summary, for the first time, we describe biological properties of curcumin during chondrogenic differentiation of chick limb bud mesenchymal cells. Curcumin suppressed chondrogenesis by stimulating apoptotic cell death and down-regulating integrin-mediated reorganization of actin cytoskeleton via modulation of Akt signaling.

Microarray Analysis of microRNA Expression during Axolotl Limb Regeneration

PubMed Central

Holman, Edna C.; Campbell, Leah J.; Hines, John; Crews, Craig M.

2012-01-01

Among vertebrates, salamanders stand out for their remarkable capacity to quickly regrow a myriad of tissues and organs after injury or amputation. The limb regeneration process in axolotls (Ambystoma mexicanum) has been well studied for decades at the cell-tissue level. While several developmental genes are known to be reactivated during this epimorphic process, less is known about the role of microRNAs in urodele amphibian limb regeneration. Given the compelling evidence that many microRNAs tightly regulate cell fate and morphogenetic processes through development and adulthood by modulating the expression (or re-expression) of developmental genes, we investigated the possibility that microRNA levels change during limb regeneration. Using two different microarray platforms to compare the axolotl microRNA expression between mid-bud limb regenerating blastemas and non-regenerating stump tissues, we found that miR-21 was overexpressed in mid-bud blastemas compared to stump tissue. Mature A. mexicanum (“Amex”) miR-21 was detected in axolotl RNA by Northern blot and differential expression of Amex-miR-21 in blastema versus stump was confirmed by quantitative RT-PCR. We identified the Amex Jagged1 as a putative target gene for miR-21 during salamander limb regeneration. We cloned the full length 3′UTR of Amex-Jag1, and our in vitro assays demonstrated that its single miR-21 target recognition site is functional and essential for the response of the Jagged1 gene to miR-21 levels. Our findings pave the road for advanced in vivo functional assays aimed to clarify how microRNAs such as miR-21, often linked to pathogenic cell growth, might be modulating the redeployment of developmental genes such as Jagged1 during regenerative processes. PMID:23028429

A regulatory network of two galectins mediates the earliest steps of avian limb skeletal morphogenesis

PubMed Central

2011-01-01

Background The skeletal elements of vertebrate embryonic limbs are prefigured by rod- and spot-like condensations of precartilage mesenchymal cells. The formation of these condensations depends on cell-matrix and cell-cell interactions, but how they are initiated and patterned is as yet unresolved. Results Here we provide evidence that galectins, β-galactoside-binding lectins with β-sandwich folding, play fundamental roles in these processes. We show that among the five chicken galectin (CG) genes, two, CG-1A, and CG-8, are markedly elevated in expression at prospective sites of condensation in vitro and in vivo, with their protein products appearing earlier in development than any previously described marker. The two molecules enhance one another's gene expression but have opposite effects on condensation formation and cartilage development in vivo and in vitro: CG-1A, a non-covalent homodimer, promotes this process, while the tandem-repeat-type CG-8 antagonizes it. Correspondingly, knockdown of CG-1A inhibits the formation of skeletal elements while knockdown of CG-8 enhances it. The apparent paradox of mutual activation at the gene expression level coupled with antagonistic roles in skeletogenesis is resolved by analysis of the direct effect of the proteins on precartilage cells. Specifically, CG-1A causes their aggregation, whereas CG-8, which has no adhesive function of its own, blocks this effect. The developmental appearance and regulation of the unknown cell surface moieties ("ligands") to which CG-1A and CG-8 bind were indicative of specific cognate- and cross-regulatory interactions. Conclusion Our findings indicate that CG-1A and CG-8 constitute a multiscale network that is a major mediator, earlier-acting than any previously described, of the formation and patterning of precartilage mesenchymal condensations in the developing limb. This network functions autonomously of limb bud signaling centers or other limb bud positional cues. PMID:21284876

Dynamic relationship of the epithelium and mesenchyme during salivary gland initiation: the role of Fgf10

PubMed Central

Wells, Kirsty L.; Gaete, Marcia; Matalova, Eva; Deutsch, Danny; Rice, David; Tucker, Abigail S.

2013-01-01

Summary Salivary glands provide an excellent model for the study of epithelial–mesenchymal interactions. We have looked at the interactions involved in the early initiation and development of murine salivary glands using classic recombination experiments and knockout mice. We show that salivary gland epithelium, at thickening and initial bud stages, is able to direct salivary gland development in non-gland pharyngeal arch mesenchyme at early stages. The early salivary gland epithelium is therefore able to induce gland development in non-gland tissue. This ability later shifts to the mesenchyme, with non-gland epithelium, such as from the limb bud, able to form a branching gland when combined with pseudoglandular stage gland mesenchyme. This shift appears to involve Fgf signalling, with signals from the epithelium inducing Fgf10 in the mesenchyme. Fgf10 then signals back to the epithelium to direct gland down-growth and bud development. These experiments highlight the importance of epithelial–mesenchymal signalling in gland initiation, controlling where, when and how many salivary glands form. PMID:24167707

Neurotrophic regulation of epidermal dedifferentiation during wound healing and limb regeneration in the axolotl (Ambystoma mexicanum).

PubMed

Satoh, A; Graham, G M C; Bryant, S V; Gardiner, D M

2008-07-15

Adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. The recently developed Accessory Limb Model (ALM) in the axolotl provides an opportunity to identify and characterize the essential signaling events that control the early steps in limb regeneration. The ALM demonstrates that limb regeneration progresses in a stepwise fashion that is dependent on signals from the wound epidermis, nerves and dermal fibroblasts from opposite sides of the limb. When all the signals are present, a limb is formed de novo. The ALM thus provides an opportunity to identify and characterize the signaling pathways that control blastema morphogenesis and limb regeneration. In the present study, we have utilized the ALM to identity the buttonhead-like zinc-finger transcription factor, Sp9, as being involved in the formation of the regeneration epithelium. Sp9 expression is induced in basal keratinocytes of the apical blastema epithelium in a pattern that is comparable to its expression in developing limb buds, and it thus is an important marker for dedifferentiation of the epidermis. Induction of Sp9 expression is nerve-dependent, and we have identified KGF as an endogenous nerve factor that induces expression of Sp9 in the regeneration epithelium.

Growth and development of the placenta in the capybara (Hydrochaeris hydrochaeris)

PubMed Central

Kanashiro, Claudia; Santos, Tatiana C; Miglino, Maria Angelica; Mess, Andrea M; Carter, Anthony M

2009-01-01

Background The guinea pig is an attractive model for human pregnancy and placentation, mainly because of its haemomonochorial placental type, but is rather small in size. Therefore, to better understand the impact of body mass, we studied placental development in the capybara which has a body mass around 50 kg and a gestation period of around 150 days. We paid attention to the development of the lobulated arrangement of the placenta, the growth of the labyrinth in the course of gestation, the differentiation of the subplacenta, and the pattern of invasion by extraplacental trophoblast. Methods Material was collected from six animals at pregnancy stages ranging from the late limb bud stage to mid gestation. Methods included latex casts, standard histology, immunohistochemistry for cytokeratin, vimentin, alpha-smooth muscle actin, and proliferating cell nuclear antigen as well as transmission electron microscopy. Results At the limb bud stage, the placenta was a pad of trophoblast covered by a layer of mesoderm from which fetal vessels were beginning to penetrate at folds in the surface. By 70 days, the placenta comprised areas of labyrinth (lobes) separated by interlobular areas. Placental growth resulted predominantly from proliferation of cellular trophoblast situated in nests at the fetal side of the placenta and along internally directed projections on fetal mesenchyme. Additional proliferation was demonstrated for cellular trophoblast within the labyrinth. Already at the limb bud stage, there was a prominent subplacenta comprising cellular and syncytial trophoblast with mesenchyme and associated blood vessels. At 90 days, differentiation was complete and similar to that seen in other hystricognath rodents. Overlap of fetal vessels and maternal blood lacunae was confirmed by latex injection of the vessels. At all stages extraplacental trophoblast was associated with the maternal arterial supply and consisted of cellular trophoblast and syncytial streamers derived from the subplacenta. Conclusion All important characteristics of placental development and organization in the capybara resembled those found in smaller hystricognath rodents including the guinea pig. These features apparently do not dependent on body size. Clearly, placentation in hystricognaths adheres to an extraordinarily stable pattern suggesting they can be used interchangeably as models of human placenta. PMID:19493333

Splenogonadal fusion with limb deficiency and micrognathia.

PubMed

Moore, P J; Hawkins, E P; Galliani, C A; Guerry-Force, M L

1997-11-01

Splenogonadal fusion (SGF) is a rare abnormality with two known types. In the continuous type, the spleen is connected to the gonad, and there are often limb defects, micrognathia, or other congenital malformations such as ventricular septal defect, anal atresia, microgastria, spina bifida, craniosynostosis, thoracopagus, diaphragmatic hernia, hypoplastic lung and abnormal lung fissures, polymicrogyria, deficient coccyx, and bifid spine C6-T3. The discontinuous type is usually not associated with congenital defects, and the gonad that fused with an accessory spleen has no connection with the native spleen. The etiology of SGF is not known. Conceivably, a teratogenic insult occurring between 5 weeks' and 8 weeks' gestation could interfere with the normal development of the spleen, gonads, and limb buds. We describe a case of splenogonadal fusion in a stillborn black boy with associated micrognathia and limb deformities. Also, we review the possible teratogenic etiologies and embryonic basis of SGF.

Sonic hedgehog acts cell-autonomously on muscle precursor cells to generate limb muscle diversity

PubMed Central

Anderson, Claire; Williams, Victoria C.; Moyon, Benjamin; Daubas, Philippe; Tajbakhsh, Shahragim; Buckingham, Margaret E.; Shiroishi, Toshihiko; Hughes, Simon M.; Borycki, Anne-Gaëlle

2012-01-01

How muscle diversity is generated in the vertebrate body is poorly understood. In the limb, dorsal and ventral muscle masses constitute the first myogenic diversification, as each gives rise to distinct muscles. Myogenesis initiates after muscle precursor cells (MPCs) have migrated from the somites to the limb bud and populated the prospective muscle masses. Here, we show that Sonic hedgehog (Shh) from the zone of polarizing activity (ZPA) drives myogenesis specifically within the ventral muscle mass. Shh directly induces ventral MPCs to initiate Myf5 transcription and myogenesis through essential Gli-binding sites located in the Myf5 limb enhancer. In the absence of Shh signaling, myogenesis is delayed, MPCs fail to migrate distally, and ventral paw muscles fail to form. Thus, Shh production in the limb ZPA is essential for the spatiotemporal control of myogenesis and coordinates muscle and skeletal development by acting directly to regulate the formation of specific ventral muscles. PMID:22987640

Forcing Epicormic Sprouts on Branch Segments of Adult Hardwoods for Softwood Cuttings

Treesearch

J. W. Van Sambeek; John E. Preece; Mark V. Coggeshall

2003-01-01

Branch segments cut from basal limbs of transitional or adult hardwood trees were forced in the greenhouse to initiate shoot growth from latent buds for the production of softwood cuttings. Forcing in February, March, and April produced 10 to 15 visible buds or elongating shoots per meter of branch wood, which was more than twice the number during any other month. On...

Enhancer elements upstream of the SHOX gene are active in the developing limb.

PubMed

Durand, Claudia; Bangs, Fiona; Signolet, Jason; Decker, Eva; Tickle, Cheryll; Rappold, Gudrun

2010-05-01

Léri-Weill Dyschondrosteosis (LWD) is a dominant skeletal disorder characterized by short stature and distinct bone anomalies. SHOX gene mutations and deletions of regulatory elements downstream of SHOX resulting in haploinsufficiency have been found in patients with LWD. SHOX encodes a homeodomain transcription factor and is known to be expressed in the developing limb. We have now analyzed the regulatory significance of the region upstream of the SHOX gene. By comparative genomic analyses, we identified several conserved non-coding elements, which subsequently were tested in an in ovo enhancer assay in both chicken limb bud and cornea, where SHOX is also expressed. In this assay, we found three enhancers to be active in the developing chicken limb, but none were functional in the developing cornea. A screening of 60 LWD patients with an intact SHOX coding and downstream region did not yield any deletion of the upstream enhancer region. Thus, we speculate that SHOX upstream deletions occur at a lower frequency because of the structural organization of this genomic region and/or that SHOX upstream deletions may cause a phenotype that differs from the one observed in LWD.

Enhancer elements upstream of the SHOX gene are active in the developing limb

PubMed Central

Durand, Claudia; Bangs, Fiona; Signolet, Jason; Decker, Eva; Tickle, Cheryll; Rappold, Gudrun

2010-01-01

Léri-Weill Dyschondrosteosis (LWD) is a dominant skeletal disorder characterized by short stature and distinct bone anomalies. SHOX gene mutations and deletions of regulatory elements downstream of SHOX resulting in haploinsufficiency have been found in patients with LWD. SHOX encodes a homeodomain transcription factor and is known to be expressed in the developing limb. We have now analyzed the regulatory significance of the region upstream of the SHOX gene. By comparative genomic analyses, we identified several conserved non-coding elements, which subsequently were tested in an in ovo enhancer assay in both chicken limb bud and cornea, where SHOX is also expressed. In this assay, we found three enhancers to be active in the developing chicken limb, but none were functional in the developing cornea. A screening of 60 LWD patients with an intact SHOX coding and downstream region did not yield any deletion of the upstream enhancer region. Thus, we speculate that SHOX upstream deletions occur at a lower frequency because of the structural organization of this genomic region and/or that SHOX upstream deletions may cause a phenotype that differs from the one observed in LWD. PMID:19997128

A Reevaluation of X-Irradiation Induced Phocomelia and Proximodistal Limb Patterning

PubMed Central

Galloway, Jenna L.; Delgado, Irene; Ros, Maria A.; Tabin, Clifford J.

2009-01-01

Phocomelia is a devastating, rare congenital limb malformation in which the long bones are shorter than normal, with the upper portion of the limb being most severely affected. In extreme cases, the hands or fingers are attached directly to the shoulder and the most proximal elements (those closest to the shoulder) are entirely missing. This disorder, previously known in both autosomal recessive and sporadic forms, showed a dramatic increase in incidence in the early 1960’s due to the tragic toxicological effects of the drug thalidomide, which had been prescribed as a mild sedative1, 2. This human birth defect is mimicked in developing chick limb buds exposed to X-irradiation3-5. Both X-irradiation5 and thalidomide-induced phocomelia5, 6 have been interpreted as patterning defects in the context of the Progress Zone Model, which states that a cell’s proximodistal (PD) identity is determined by the length of time spent in a distal limb region termed the “Progress Zone” 7. Indeed, studies of X-irradiation induced phocomelia have served as one of the two major experimental lines of evidence supporting the validity of the Progress Zone Model. Here, using a combination of molecular analysis and lineage tracing, we show that X-irradiation-induced phocomelia is fundamentally not a patterning defect, but rather results from a time-dependent loss of skeletal progenitors. As skeletal condensation proceeds from the shoulder to fingers (in a proximal to distal direction), the proximal elements are differentially affected in limb buds exposed to radiation at early stages. This conclusion changes the framework for considering the effect of thalidomide and other forms of phocomelia, suggesting the possibility that the etiology lies not in a defect in the patterning process, but rather in progenitor cell survival and differentiation. Moreover, molecular evidence that PD patterning is unaffected following X-irradiation does not support the predictions of the Progress Zone Model. PMID:19553938

A reevaluation of X-irradiation-induced phocomelia and proximodistal limb patterning.

PubMed

Galloway, Jenna L; Delgado, Irene; Ros, Maria A; Tabin, Clifford J

2009-07-16

Phocomelia is a devastating, rare congenital limb malformation in which the long bones are shorter than normal, with the upper portion of the limb being most severely affected. In extreme cases, the hands or fingers are attached directly to the shoulder and the most proximal elements (those closest to the shoulder) are entirely missing. This disorder, previously known in both autosomal recessive and sporadic forms, showed a marked increase in incidence in the early 1960s due to the tragic toxicological effects of the drug thalidomide, which had been prescribed as a mild sedative. This human birth defect is mimicked in developing chick limb buds exposed to X-irradiation. Both X-irradiation and thalidomide-induced phocomelia have been interpreted as patterning defects in the context of the progress zone model, which states that a cell's proximodistal identity is determined by the length of time spent in a distal limb region termed the 'progress zone'. Indeed, studies of X-irradiation-induced phocomelia have served as one of the two major experimental lines of evidence supporting the validity of the progress zone model. Here, using a combination of molecular analysis and lineage tracing in chick, we show that X-irradiation-induced phocomelia is fundamentally not a patterning defect, but rather results from a time-dependent loss of skeletal progenitors. Because skeletal condensation proceeds from the shoulder to fingers (in a proximal to distal direction), the proximal elements are differentially affected in limb buds exposed to radiation at early stages. This conclusion changes the framework for considering the effect of thalidomide and other forms of phocomelia, suggesting the possibility that the aetiology lies not in a defect in the patterning process, but rather in progenitor cell survival and differentiation. Moreover, molecular evidence that proximodistal patterning is unaffected after X-irradiation does not support the predictions of the progress zone model.

Differentiation of cartilaginous anlage in entire embryonic mouse limbs cultured in a rotating bioreactor.

NASA Astrophysics Data System (ADS)

Duke, P.; Oakley, C.; Montufar-Solis, D.

The embryonic mammalian limb is sensitive both in vivo and in vitro to changes in gravitational force. Hypergravity of centrifugation and microgravity of space decreased size of elements due to precocious or delayed chondrogenesis respectively. In recapitulating spaceflight experiments, premetatarsals were cultured in suspension in a low stress, low sheer rotating bioreactor, and found to be shorter than those cultured in standard culture dishes, and cartilage development was delayed. This study only measured length of the metatarsals, and did not account for possible changes in width and/or in form of the skeletal elements. Shorter cartilage elements in limbbuds cultured in the bioreactor may be due to the ability of the system to reproduce a more in vivo 3D shape than traditional organ cultures. Tissues subjected to traditional organ cultures become flattened by their own weight, attachment to the filter, and restrictions imposed by nutrient diffusion. The purpose of the current experiment was to determine if entire limb buds could be successfully cultured in the bioreactor, and to compare the effects on 3D shape with that of culturing in a culture dish system. Fore and hind limbs from E11-E13 ICR mouse embryos were placed either in the bioreactor, in Trowell culture, or fixed as controls. Limbbuds were cultured for six days, fixed, and processed either as whole mounts or embedded for histology. Qualitative analysis revealed that the Trowell culture specimens were flattened, while bioreactor culture specimens had a more in vivo-like 3D limb shape. Sections of limbbuds from both types of cultures had excellent cartilage differentiation, with apparently more cell maturation, and hypertrophy in the specimens cultured in the bioreactor. Morphometric quantitation of the cartilaginous elements for comparisons of the two culture systems was complicated due to some limb buds fusing together during culture. This problem was especially noticeable in the younger limbs, and may be rectified by embedding the limbs in a matrix (e.g. alginate) to maintain integrity of the tissue while in culture in the bioreactor. The bioreactor supported differentiation of skeletal elements in entire limbs, and maintained better external limb morphology than did the Trowell system. Supported by NIH/NIDCR Training Grant T358DE07252-08.

Human mesenchymal stem cells derived from limb bud can differentiate into all three embryonic germ layers lineages.

PubMed

Jiao, Fei; Wang, Juan; Dong, Zhao-Lun; Wu, Min-Juan; Zhao, Ting-Bao; Li, Dan-Dan; Wang, Xin

2012-08-01

Mesenchymal stem cells (MSCs) have been isolated from many sources, including adults and fetuses. Previous studies have demonstrated that, compared with their adult counterpart, fetal MSCs with several remarkable advantages may be a better resource for clinical applications. In this study, we successfully isolated a rapidly proliferating cell population from limb bud of aborted fetus and termed them "human limb bud-derived mesenchymal stem cells" (hLB-MSCs). Characteristics of their morphology, phenotype, cell cycle, and differentiation properties were analyzed. These adherent cell populations have a typically spindle-shaped morphology. Flow cytometry analysis showed that hLB-MSCs are positive for CD13, CD29, CD90, CD105, and CD106, but negative for CD3, CD4, CD5, CD11b, CD14, CD15, CD34, CD45, CD45RA, and HLA-DR. The detection of cell cycle from different passages indicated that hLB-MSCs have a similar potential for propagation during long culture in vitro. The most novel finding here is that, in addition to their mesodermal differentiation (osteoblasts and adipocytes), hLB-MSCs can also differentiated into extramesenchymal lineages, such as neural (ectoderm) and hepatic (endoderm) progenies. These results indicate that hLB-MSCs have a high level of plasticity and can differentiate into cell lineages from all three embryonic layers in vitro.

Conditional inactivation of Has2 reveals a crucial role for hyaluronan in skeletal growth, patterning, chondrocyte maturation and joint formation in the developing limb.

PubMed

Matsumoto, Kazu; Li, Yingcui; Jakuba, Caroline; Sugiyama, Yoshinori; Sayo, Tetsuya; Okuno, Misako; Dealy, Caroline N; Toole, Bryan P; Takeda, Junji; Yamaguchi, Yu; Kosher, Robert A

2009-08-01

The glycosaminoglycan hyaluronan (HA) is a structural component of extracellular matrices and also interacts with cell surface receptors to directly influence cell behavior. To explore functions of HA in limb skeletal development, we conditionally inactivated the gene for HA synthase 2, Has2, in limb bud mesoderm using mice that harbor a floxed allele of Has2 and mice carrying a limb mesoderm-specific Prx1-Cre transgene. The skeletal elements of Has2-deficient limbs are severely shortened, indicating that HA is essential for normal longitudinal growth of all limb skeletal elements. Proximal phalanges are duplicated in Has2 mutant limbs indicating an involvement of HA in patterning specific portions of the digits. The growth plates of Has2-deficient skeletal elements are severely abnormal and disorganized, with a decrease in the deposition of aggrecan in the matrix and a disruption in normal columnar cellular relationships. Furthermore, there is a striking reduction in the number of hypertrophic chondrocytes and in the expression domains of markers of hypertrophic differentiation in the mutant growth plates, indicating that HA is necessary for the normal progression of chondrocyte maturation. In addition, secondary ossification centers do not form in the central regions of Has2 mutant growth plates owing to a failure of hypertrophic differentiation. In addition to skeletal defects, the formation of synovial joint cavities is defective in Has2-deficient limbs. Taken together, our results demonstrate that HA has a crucial role in skeletal growth, patterning, chondrocyte maturation and synovial joint formation in the developing limb.

Computation Modeling of Limb-bud Dysmorphogenesis: Predicting Cellular Dynamics and Key Events in Developmental Toxicity with a Multicellular Systems Model (FutureToxII)

EPA Science Inventory

Congenital limb malformations are among the most frequent malformation occurs in humans, with a frequency of about 1 in 500 to 1 in 1000 human live births. ToxCast is profiling the bioactivity of thousands of chemicals based on high-throughput (HTS) and computational methods that...

Dynamical mechanisms for skeletal pattern formation in the vertebrate limb.

PubMed Central

Hentschel, H. G. E.; Glimm, Tilmann; Glazier, James A.; Newman, Stuart A.

2004-01-01

We describe a 'reactor-diffusion' mechanism for precartilage condensation based on recent experiments on chondrogenesis in the early vertebrate limb and additional hypotheses. Cellular differentiation of mesenchymal cells into subtypes with different fibroblast growth factor (FGF) receptors occurs in the presence of spatio-temporal variations of FGFs and transforming growth factor-betas (TGF-betas). One class of differentiated cells produces elevated quantities of the extracellular matrix protein fibronectin, which initiates adhesion-mediated preskeletal mesenchymal condensation. The same class of cells also produces an FGF-dependent laterally acting inhibitor that keeps condensations from expanding beyond a critical size. We show that this 'reactor-diffusion' mechanism leads naturally to patterning consistent with skeletal form, and describe simulations of spatio-temporal distribution of these differentiated cell types and the TGF-beta and inhibitor concentrations in the developing limb bud. PMID:15306292

The evolutionary history of the development of the pelvic fin/hindlimb

PubMed Central

Don, Emily K; Currie, Peter D; Cole, Nicholas J

2013-01-01

The arms and legs of man are evolutionarily derived from the paired fins of primitive jawed fish. Few evolutionary changes have attracted as much attention as the origin of tetrapod limbs from the paired fins of ancestral fish. The hindlimbs of tetrapods are derived from the pelvic fins of ancestral fish. These evolutionary origins can be seen in the examination of shared gene and protein expression patterns during the development of pelvic fins and tetrapod hindlimbs. The pelvic fins of fish express key limb positioning, limb bud induction and limb outgrowth genes in a similar manner to that seen in hindlimb development of higher vertebrates. We are now at a point where many of the key players in the development of pelvic fins and vertebrate hindlimbs have been identified and we can now readily examine and compare mechanisms between species. This is yielding fascinating insights into how the developmental programme has altered during evolution and how that relates to anatomical change. The role of pelvic fins has also drastically changed over evolutionary history, from playing a minor role during swimming to developing into robust weight-bearing limbs. In addition, the pelvic fins/hindlimbs have been lost repeatedly in diverse species over evolutionary time. Here we review the evolution of pelvic fins and hindlimbs within the context of the changes in anatomical structure and the molecular mechanisms involved. PMID:22913749

Wnt and FGF signals interact to coordinate growth with cell fate specification during limb development.

PubMed

ten Berge, Derk; Brugmann, Samantha A; Helms, Jill A; Nusse, Roel

2008-10-01

A fundamental question in developmental biology is how does an undifferentiated field of cells acquire spatial pattern and undergo coordinated differentiation? The development of the vertebrate limb is an important paradigm for understanding these processes. The skeletal and connective tissues of the developing limb all derive from a population of multipotent progenitor cells located in its distal tip. During limb outgrowth, these progenitors segregate into a chondrogenic lineage, located in the center of the limb bud, and soft connective tissue lineages located in its periphery. We report that the interplay of two families of signaling proteins, fibroblast growth factors (FGFs) and Wnts, coordinate the growth of the multipotent progenitor cells with their simultaneous segregation into these lineages. FGF and Wnt signals act together to synergistically promote proliferation while maintaining the cells in an undifferentiated, multipotent state, but act separately to determine cell lineage specification. Withdrawal of both signals results in cell cycle withdrawal and chondrogenic differentiation. Continued exposure to Wnt, however, maintains proliferation and re-specifies the cells towards the soft connective tissue lineages. We have identified target genes that are synergistically regulated by Wnts and FGFs, and show how these factors actively suppress differentiation and promote growth. Finally, we show how the spatial restriction of Wnt and FGF signals to the limb ectoderm, and to a specialized region of it, the apical ectodermal ridge, controls the distribution of cell behaviors within the growing limb, and guides the proper spatial organization of the differentiating tissues.

Transient Inhibition of FGFR2b-Ligands Signaling Leads to Irreversible Loss of Cellular β-Catenin Organization and Signaling in AER during Mouse Limb Development

PubMed Central

Tabatabai, Reza; Baptista, Sheryl; Tiozzo, Caterina; Carraro, Gianni; Wheeler, Matthew; Barreto, Guillermo; Braun, Thomas; Li, Xiaokun; Hajihosseini, Mohammad K.; Bellusci, Saverio

2013-01-01

The vertebrate limbs develop through coordinated series of inductive, growth and patterning events. Fibroblast Growth Factor receptor 2b (FGFR2b) signaling controls the induction of the Apical Ectodermal Ridge (AER) but its putative roles in limb outgrowth and patterning, as well as in AER morphology and cell behavior have remained unclear. We have investigated these roles through graded and reversible expression of soluble dominant-negative FGFR2b molecules at various times during mouse limb development, using a doxycycline/transactivator/tet(O)-responsive system. Transient attenuation (≤24 hours) of FGFR2b-ligands signaling at E8.5, prior to limb bud induction, leads mostly to the loss or truncation of proximal skeletal elements with less severe impact on distal elements. Attenuation from E9.5 onwards, however, has an irreversible effect on the stability of the AER, resulting in a progressive loss of distal limb skeletal elements. The primary consequences of FGFR2b-ligands attenuation is a transient loss of cell adhesion and down-regulation of P63, β1-integrin and E-cadherin, and a permanent loss of cellular β-catenin organization and WNT signaling within the AER. Combined, these effects lead to the progressive transformation of the AER cells from pluristratified to squamous epithelial-like cells within 24 hours of doxycycline administration. These findings show that FGFR2b-ligands signaling has critical stage-specific roles in maintaining the AER during limb development. PMID:24167544

Conditional inactivation of Has2 reveals a crucial role for hyaluronan in skeletal growth, patterning, chondrocyte maturation and joint formation in the developing limb

PubMed Central

Matsumoto, Kazu; Li, Yingcui; Jakuba, Caroline; Sugiyama, Yoshinori; Sayo, Tetsuya; Okuno, Misako; Dealy, Caroline N.; Toole, Bryan P.; Takeda, Junji; Yamaguchi, Yu; Kosher, Robert A.

2009-01-01

Summary The glycosaminoglycan hyaluronan (HA) is a structural component of extracellular matrices and also interacts with cell surface receptors to directly influence cell behavior. To explore functions of HA in limb skeletal development, we conditionally inactivated the gene for HA synthase 2, Has2, in limb bud mesoderm using mice that harbor a floxed allele of Has2 and mice carrying a limb mesoderm-specific Prx1-Cre transgene. The skeletal elements of Has2-deficient limbs are severely shortened, indicating that HA is essential for normal longitudinal growth of all limb skeletal elements. Proximal phalanges are duplicated in Has2 mutant limbs indicating an involvement of HA in patterning specific portions of the digits. The growth plates of Has2-deficient skeletal elements are severely abnormal and disorganized, with a decrease in the deposition of aggrecan in the matrix and a disruption in normal columnar cellular relationships. Furthermore, there is a striking reduction in the number of hypertrophic chondrocytes and in the expression domains of markers of hypertrophic differentiation in the mutant growth plates, indicating that HA is necessary for the normal progression of chondrocyte maturation. In addition, secondary ossification centers do not form in the central regions of Has2 mutant growth plates owing to a failure of hypertrophic differentiation. In addition to skeletal defects, the formation of synovial joint cavities is defective in Has2-deficient limbs. Taken together, our results demonstrate that HA has a crucial role in skeletal growth, patterning, chondrocyte maturation and synovial joint formation in the developing limb. PMID:19633173

Right upper limb bud triplication and polythelia, left sided hemihypertrophy and congenital hip dislocation, facial dysmorphism, congenital heart disease, and scoliosis: disorganisation-like spectrum or patterning gene defect?

PubMed

Sabry, M A; al-Saleh, Q; al-Saw'an, R; al-Awadi, S A; Farag, T I

1995-07-01

A Somali female baby with right upper limb triplication, polythelia, left sided hemihypertrophy, congenital hip dislocation, facial dysmorphism, congenital heart disease, and scoliosis is described. It seems that the above described pattern of anomalies has not been reported before. The possible developmental genetic mechanism responsible for this phenotype is briefly discussed.

Rapid transient isoform-specific neuregulin1 transcription in motor neurons is regulated by neurotrophic factors and axon-target interactions.

PubMed

Wang, Jiajing; Hmadcha, Abdelkrim; Zakarian, Vaagn; Song, Fei; Loeb, Jeffrey A

2015-09-01

The neuregulins (NRGs) are a family of alternatively spliced factors that play important roles in nervous system development and disease. In motor neurons, NRG1 expression is regulated by activity and neurotrophic factors, however, little is known about what controls isoform-specific transcription. Here we show that NRG1 expression in the chick embryo increases in motor neurons that have extended their axons and that limb bud ablation before motor axon outgrowth prevents this induction, suggesting a trophic role from the developing limb. Consistently, NRG1 induction after limb bud ablation can be rescued by adding back the neurotrophic factors BDNF and GDNF. Mechanistically, BDNF induces a rapid and transient increase in type I and type III NRG1 mRNAs that peak at 4h in rat embryonic ventral spinal cord cultures. Blocking MAPK or PI3K signaling or blocking transcription with Actinomycin D blocks BDNF induced NRG1 gene induction. BDNF had no effect on mRNA degradation, suggesting that transcriptional activation rather than message stability is important. Furthermore, BDNF activates a reporter construct that includes 700bp upstream of the type I NRG1 start site. Protein synthesis is also required for type I NRG1 mRNA transcription as cycloheximide produced a super-induction of type I, but not type III NRG1 mRNA, possibly through a mechanism involving sustained activation of MAPK and PI3K. These results reveal the existence of highly responsive, transient transcriptional regulatory mechanisms that differentially modulate NRG1 isoform expression as a function of extracellular and intracellular signaling cascades and mediated by neurotrophic factors and axon-target interactions. Copyright © 2015 Elsevier Inc. All rights reserved.

Right upper limb bud triplication and polythelia, left sided hemihypertrophy and congenital hip dislocation, facial dysmorphism, congenital heart disease, and scoliosis: disorganisation-like spectrum or patterning gene defect?

PubMed Central

Sabry, M A; al-Saleh, Q; al-Saw'an, R; al-Awadi, S A; Farag, T I

1995-01-01

A Somali female baby with right upper limb triplication, polythelia, left sided hemihypertrophy, congenital hip dislocation, facial dysmorphism, congenital heart disease, and scoliosis is described. It seems that the above described pattern of anomalies has not been reported before. The possible developmental genetic mechanism responsible for this phenotype is briefly discussed. Images PMID:7562971

Morphogenesis and evolution of vertebrate appendicular muscle

PubMed Central

HAINES, LYNN; CURRIE, PETER D.

2001-01-01

Two different modes are utilised by vertebrate species to generate the appendicular muscle present within fins and limbs. Primitive Chondricthyan or cartilaginous fishes use a primitive mode of muscle formation to generate the muscle of the fins. Direct epithelial myotomal extensions invade the fin and generate the fin muscles while remaining in contact with the myotome. Embryos of amniotes such as chick and mouse use a similar mechanism to that deployed in the bony teleost species, zebrafish. Migratory mesenchymal myoblasts delaminate from fin/limb level somites, migrate to the fin/limb field and differentiate entirely within the context of the fin/limb bud. Migratory fin and limb myoblasts express identical genes suggesting that they possess both morphogenetic and molecular identity. We conclude that the mechanisms controlling tetrapod limb muscle formation arose prior to the Sarcopterygian or tetrapod radiation. PMID:11523824

Ectodermal Wnt6 is an early negative regulator of limb chondrogenesis in the chicken embryo

PubMed Central

2010-01-01

Background Pattern formation of the limb skeleton is regulated by a complex interplay of signaling centers located in the ectodermal sheath and mesenchymal core of the limb anlagen, which results, in the forelimb, in the coordinate array of humerus, radius, ulna, carpals, metacarpals and digits. Much less understood is why skeletal elements form only in the central mesenchyme of the limb, whereas muscle anlagen develop in the peripheral mesenchyme ensheathing the chondrogenic center. Classical studies have suggested a role of the limb ectoderm as a negative regulator of limb chondrogenesis. Results In this paper, we investigated the molecular nature of the inhibitory influence of the ectoderm on limb chondrogenesis in the avian embryo in vivo. We show that ectoderm ablation in the early limb bud leads to increased and ectopic expression of early chondrogenic marker genes like Sox9 and Collagen II, indicating that the limb ectoderm inhibits limb chondrogenesis at an early stage of the chondrogenic cascade. To investigate the molecular nature of the inhibitory influence of the ectoderm, we ectopically expressed Wnt6, which is presently the only known Wnt expressed throughout the avian limb ectoderm, and found that Wnt6 overexpression leads to reduced expression of the early chondrogenic marker genes Sox9 and Collagen II. Conclusion Our results suggest that the inhibitory influence of the ectoderm on limb chondrogenesis acts on an early stage of chondrogenesis upsteam of Sox9 and Collagen II. We identify Wnt6 as a candidate mediator of ectodermal chondrogenic inhibition in vivo. We propose a model of Wnt-mediated centripetal patterning of the limb by the surface ectoderm. PMID:20334703

Molecular anatomy of the developing limb in the coquí frog, Eleutherodactylus coqui.

PubMed

Gross, Joshua B; Kerney, Ryan; Hanken, James; Tabin, Clifford J

2011-01-01

The vertebrate limb demonstrates remarkable similarity in basic organization across phylogenetically disparate groups. To gain further insight into how this morphological similarity is maintained in different developmental contexts, we explored the molecular anatomy of size-reduced embryos of the Puerto Rican coquí frog, Eleutherodactylus coqui. This animal demonstrates direct development, a life-history strategy marked by rapid progression from egg to adult and absence of a free-living, aquatic larva. Nonetheless, coquí exhibits a basal anuran limb structure, with four toes on the forelimb and five toes on the hind limb. We investigated the extent to which coquí limb bud development conforms to the model of limb development derived from amniote studies. Toward this end, we characterized dynamic patterns of expression for 13 critical patterning genes across three principle stages of limb development. As expected, most genes demonstrate expression patterns that are essentially unchanged compared to amniote species. For example, we identified an EcFgf8-expression domain within the apical ectodermal ridge (AER). This expression pattern defines a putatively functional AER signaling domain, despite the absence of a morphological ridge in coquí embryos. However, two genes, EcMeis2 and EcAlx4, demonstrate altered domains of expression, which imply a potential shift in gene function between coquí frogs and amniote model systems. Unexpectedly, several genes thought to be critical for limb patterning in other systems, including EcFgf4, EcWnt3a, EcWnt7a, and EcGremlin, demonstrated no evident expression pattern in the limb at the three stages we analyzed. The absence of EcFgf4 and EcWnt3a expression during limb patterning is perhaps not surprising, given that neither gene is critical for proper limb development in the mouse, based on knockout and expression analyses. In contrast, absence of EcWnt7a and EcGremlin is surprising, given that expression of these molecules appears to be absolutely essential in all other model systems so far examined. Although this analysis substantiates the existence of a core set of ancient limb-patterning molecules, which likely mediate identical functions across highly diverse vertebrate forms, it also reveals remarkable evolutionary flexibility in the genetic control of a conserved morphological pattern across evolutionary time. © 2011 Wiley Periodicals, Inc.

Modeling digits. Digit patterning is controlled by a Bmp-Sox9-Wnt Turing network modulated by morphogen gradients.

PubMed

Raspopovic, J; Marcon, L; Russo, L; Sharpe, J

2014-08-01

During limb development, digits emerge from the undifferentiated mesenchymal tissue that constitutes the limb bud. It has been proposed that this process is controlled by a self-organizing Turing mechanism, whereby diffusible molecules interact to produce a periodic pattern of digital and interdigital fates. However, the identities of the molecules remain unknown. By combining experiments and modeling, we reveal evidence that a Turing network implemented by Bmp, Sox9, and Wnt drives digit specification. We develop a realistic two-dimensional simulation of digit patterning and show that this network, when modulated by morphogen gradients, recapitulates the expression patterns of Sox9 in the wild type and in perturbation experiments. Our systems biology approach reveals how a combination of growth, morphogen gradients, and a self-organizing Turing network can achieve robust and reproducible pattern formation. Copyright © 2014, American Association for the Advancement of Science.

FGFR3 is a target of the homeobox transcription factor SHOX in limb development.

PubMed

Decker, Eva; Durand, Claudia; Bender, Sebastian; Rödelsperger, Christian; Glaser, Anne; Hecht, Jochen; Schneider, Katja U; Rappold, Gudrun

2011-04-15

The short stature homeobox gene SHOX encodes a transcription factor which is important for normal limb development. In humans, SHOX deficiency has been associated with various short stature syndromes including Leri-Weill dyschondrosteosis (LWD), Langer mesomelic dysplasia and Turner syndrome as well as non-syndromic idiopathic short stature. A common feature of these syndromes is disproportionate short stature with a particular shortening of the forearms and lower legs. In our studies employing microarray analyses and cell culture experiments, we revealed a strong positive effect of SHOX on the expression of the fibroblast growth factor receptor gene FGFR3, another well-known factor for limb development. Luciferase reporter gene assays show that SHOX activates the extended FGFR3 promoter, and results from chromatin immunoprecipitation (ChIP)-sequencing, ChIP and electrophoretic mobility shift assay experiments suggest a direct binding of SHOX to multiple upstream sequences of FGFR3. To further investigate these regulations in a cellular system for limb development, the effect of viral overexpression of Shox in limb bud derived chicken micromass cultures was tested. We found that Fgfr3 was negatively regulated by Shox, as demonstrated by quantitative real-time polymerase chain reaction and in situ hybridization. This repressive effect might explain the almost mutually exclusive expression patterns of Fgfr3 and Shox in embryonic chicken limbs. A negative regulation that occurs mainly in the mesomelic segments, a region where SHOX is known to be strongly expressed, offers a possible explanation for the phenotypes seen in patients with FGFR3 (e.g. achondroplasia) and SHOX defects (e.g. LWD). In summary, these data present a link between two frequent short stature phenotypes.

Nipbl and mediator cooperatively regulate gene expression to control limb development.

PubMed

Muto, Akihiko; Ikeda, Shingo; Lopez-Burks, Martha E; Kikuchi, Yutaka; Calof, Anne L; Lander, Arthur D; Schilling, Thomas F

2014-09-01

Haploinsufficiency for Nipbl, a cohesin loading protein, causes Cornelia de Lange Syndrome (CdLS), the most common "cohesinopathy". It has been proposed that the effects of Nipbl-haploinsufficiency result from disruption of long-range communication between DNA elements. Here we use zebrafish and mouse models of CdLS to examine how transcriptional changes caused by Nipbl deficiency give rise to limb defects, a common condition in individuals with CdLS. In the zebrafish pectoral fin (forelimb), knockdown of Nipbl expression led to size reductions and patterning defects that were preceded by dysregulated expression of key early limb development genes, including fgfs, shha, hand2 and multiple hox genes. In limb buds of Nipbl-haploinsufficient mice, transcriptome analysis revealed many similar gene expression changes, as well as altered expression of additional classes of genes that play roles in limb development. In both species, the pattern of dysregulation of hox-gene expression depended on genomic location within the Hox clusters. In view of studies suggesting that Nipbl colocalizes with the mediator complex, which facilitates enhancer-promoter communication, we also examined zebrafish deficient for the Med12 Mediator subunit, and found they resembled Nipbl-deficient fish in both morphology and gene expression. Moreover, combined partial reduction of both Nipbl and Med12 had a strongly synergistic effect, consistent with both molecules acting in a common pathway. In addition, three-dimensional fluorescent in situ hybridization revealed that Nipbl and Med12 are required to bring regions containing long-range enhancers into close proximity with the zebrafish hoxda cluster. These data demonstrate a crucial role for Nipbl in limb development, and support the view that its actions on multiple gene pathways result from its influence, together with Mediator, on regulation of long-range chromosomal interactions.

Effects of Ethylene Glycol Monomethyl Ether and Its Metabolite, 2-Methoxyacetic Acid, on Organogenesis Stage Mouse Limbs In Vitro

PubMed Central

Dayan, Caroline; Hales, Barbara F

2014-01-01

Exposure to ethylene glycol monomethyl ether (EGME), a glycol ether compound found in numerous industrial products, or to its active metabolite, 2-methoxyacetic acid (2-MAA), increases the incidence of developmental defects. Using an in vitro limb bud culture system, we tested the hypothesis that the effects of EGME on limb development are mediated by 2-MAA-induced alterations in acetylation programming. Murine gestation day 12 embryonic forelimbs were exposed to 3, 10, or 30 mM EGME or 2-MAA in culture for 6 days to examine effects on limb morphology; limbs were cultured for 1 to 24 hr to monitor effects on the acetylation of histones (H3K9 and H4K12), a nonhistone protein, p53 (p53K379), and markers for cell cycle arrest (p21) and apoptosis (cleaved caspase-3). EGME had little effect on limb morphology and no significant effects on the acetylation of histones or p53 or on biomarkers for cell cycle arrest or apoptosis. In contrast, 2-MAA exposure resulted in a significant concentration-dependent increase in limb abnormalities. 2-MAA induced the hyperacetylation of histones H3K9Ac and H4K12Ac at all concentrations tested (3, 10, and 30 mM). Exposure to 10 or 30 mM 2-MAA significantly increased acetylation of p53 at K379, p21 expression, and caspase-3 cleavage. Thus, 2-MAA, the proximate metabolite of EGME, disrupts limb development in vitro, modifies acetylation programming, and induces biomarkers of cell cycle arrest and apoptosis PMID:24798094

An historical perspective on the pioneering experiments of John Saunders.

PubMed

Tickle, Cheryll

2017-09-15

John Saunders was a highly skilled embryologist who pioneered the study of limb development. His studies on chick embryos provided the fundamental framework for understanding how vertebrate limbs develop. This framework inspired generations of scientists and formed the bridge from experimental embryology to molecular mechanisms. Saunders investigated how feathers become organized into tracts in the skin of the chick wing and also identified regions of programmed cell death. He discovered that a region of thickened ectoderm that rims the chick wing bud - the apical ectodermal ridge - is required for outgrowth and the laying down of structures along the proximo-distal axis (long axis) of the wing, identified the zone of polarizing activity (ZPA; polarizing region) that controls development across the anteroposterior axis ("thumb to little finger "axis) and contributed to uncovering the importance of the ectoderm in development of structures along the dorso-ventral axis ( "back of hand to palm" axis). This review looks in depth at some of his original papers and traces how he made the crucial findings about how limbs develop, considering these findings both in the context of contemporary knowledge at the time and also in terms of their immediate impact on the field. Copyright © 2017 Elsevier Inc. All rights reserved.

Comprehensive analysis of fibroblast growth factor receptor expression patterns during chick forelimb development.

PubMed

Sheeba, Caroline J; Andrade, Raquel P; Duprez, Delphine; Palmeirim, Isabel

2010-01-01

Specific interactions between fibroblast growth factors (Fgf1-22) and their tyrosine kinase receptors (FgfR1-4) activate different signalling pathways that are responsible for the biological processes in which Fgf signalling is implicated during embryonic development. In the chick, several Fgf ligands (Fgf2, 4, 8, 9, 10, 12, 13 and 18) and the four FgfRs (FgfR 1, 2, 3 and 4) have been reported to be expressed in the developing limb. The precise spatial and temporal expression of these transcripts is important to guide the limb bud to develop into a wing/leg. In this paper, we present a detailed and systematic analysis of the expression patterns of FgfR1, 2, 3 and 4 throughout chick wing development, by in situ hybridisation on whole mounts and sections. Moreover, we characterize for the first time the different isoforms of FGFR1-3 by analysing their differential expression in limb ectoderm and mesodermal tissues, using RT-PCR and in situ hybridisation on sections. Finally, isoform-specific sequences for FgfR1IIIb, FgfR1IIIc, FgfR3IIIb and FgfR3IIIc were determined and deposited in GenBank with the following accession numbers: GU053725, GU065444, GU053726, GU065445, respectively.

Modeling limb-bud dysmorphogenesis in a predictive virtual embryo model

EPA Science Inventory

ToxCast is profiling the bioactivity of thousands of chemicals based on high-throughput screening (HTS) and computational methods that integrate knowledge of biological systems and in vivo toxicities (www.epa.gov/ncct/toxcast/). Many ToxCast assays assess signaling pathways and c...

Transcriptomic analysis of Portunus trituberculatus reveals a critical role for WNT4 and WNT signalling in limb regeneration.

PubMed

Liu, Lei; Fu, Yuanyuan; Zhu, Fang; Mu, Changkao; Li, Ronghua; Song, Weiwei; Shi, Ce; Ye, Yangfang; Wang, Chunlin

2018-06-05

The swimming crab (Portunus trituberculatus) is among the most economically important seawater crustacean species in Asia. Despite its commercial importance and being well-studied status, genomic and transcriptomic data are scarce for this crab species. In the present study, limb bud tissue was collected at different developmental stages post amputation for transcriptomic analysis. Illumina RNA-sequencing was applied to characterise the limb regeneration transcriptome and identify the most characteristic genes. A total of 289,018 transcripts were obtained by clustering and assembly of clean reads, producing 150,869 unigenes with an average length of 956 bp. Subsequent analysis revealed WNT signalling as the key pathway involved in limb regeneration, with WNT4 a key mediator. Overall, limb regeneration appears to be regulated by multiple signalling pathways, with numerous cell differentiation, muscle growth, moult, metabolism, and immune-related genes upregulated, including WNT4, LAMA, FIP2, FSTL5, TNC, HUS1, SWI5, NCGL, SLC22, PLA2, Tdc2, SMOX, GDH, and SMPD4. This is the first experimental study done on regenerating claws of P. trituberculatus. These findings expand existing sequence resources for crab species, and will likely accelerate research into regeneration and development in crustaceans, particularly functional studies on genes involved in limb regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

Intrinsic properties of limb bud cells can be differentially reset.

PubMed

Saiz-Lopez, Patricia; Chinnaiya, Kavitha; Towers, Matthew; Ros, Maria A

2017-02-01

An intrinsic timing mechanism specifies the positional values of the zeugopod (i.e. radius/ulna) and then autopod (i.e. wrist/digits) segments during limb development. Here, we have addressed whether this timing mechanism ensures that patterning events occur only once by grafting GFP-expressing autopod progenitor cells to the earlier host signalling environment of zeugopod progenitor cells. We show by detecting Hoxa13 expression that early and late autopod progenitors fated for the wrist and phalanges, respectively, both contribute to the entire host autopod, indicating that the autopod positional value is irreversibly determined. We provide evidence that Hoxa13 provides an autopod-specific positional value that correctly allocates cells into the autopod, most likely through the control of cell-surface properties as shown by cell-cell sorting analyses. However, we demonstrate that only the earlier autopod cells can adopt the host proliferation rate to permit normal morphogenesis. Therefore, our findings reveal that the ability of embryonic cells to differentially reset their intrinsic behaviours confers robustness to limb morphogenesis. We speculate that this plasticity could be maintained beyond embryogenesis in limbs with regenerative capacity. © 2017. Published by The Company of Biologists Ltd.

Preaxial Polydactyly in Sost/Sostdc1 Double Knockouts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yee, C M; Collette, N M; Loots, G G

2011-07-29

In the United States, {approx}5% are born with congenital birth defects due to abnormal function of cellular processes and interactions. Sclerosteosis, a rare autosomal recessive disease, causes hyperostosis of the axial and appendicular skeleton, and patients present radial deviation, digit syndactyly, nail dysplasia, and overall high bone mineral density. Sclerosteosis is due to a loss of function of sclerostin (Sost). Sost is a Wnt (abbrev.) antagonist; when mutated, nonfunctional Sost results in hyperactive osteoblast activity which leads to abnormal high bone mass. Previous studies have shown that Sost overexpression in transgenic mice causes reduced bone mineral density and a varietymore » of limb phenotypes ranging from lost, fused, and split phalanges. Consistent with clinical manifestations of Sclerosteosis, Sost knockout mice exhibit increased generalized bone mineral density and syndactyly of the digits. Sostdc1 is a paralog of Sost that has also been described as an antagonist of Wnt signaling, in developing tooth buds. Unlike Sost knockouts, Sostdc1 null mice do not display any limb abnormalities. To determine if Sost and Sostdc1 have redundant functions during limb patterning, we examined Sost; Sostdc1 mice determined that they exhibit a novel preaxial polydactyly phenotype with a low penetrance. LacZ staining, skeletal preparations, and in situ hybridization experiments were used to help characterize this novel phenotype and understand how this phenotype develops. We find Sost and Sostdc1 to have complementary expression patterns during limb development, and the loss of their expression alters the transcription of several key limb regulators, such as Fgf8, Shh and Grem.« less

Msx genes are expressed in the carapacial ridge of turtle shell: a study of the European pond turtle, Emys orbicularis.

PubMed

Vincent, Christine; Bontoux, Martine; Le Douarin, Nicole M; Pieau, Claude; Monsoro-Burq, Anne-Hélène

2003-09-01

The turtle shell forms by extensive ossification of dermis ventrally and dorsally. The carapacial ridge (CR) controls early dorsal shell formation and is thought to play a similar role in shell growth as the apical ectodermal ridge during limb development. However, the molecular mechanisms underlying carapace development are still unknown. Msx genes are involved in the development of limb mesenchyme and of various skeletal structures. In particular, precocious Msx expression is recorded in skeletal precursors that develop close to the ectoderm, such as vertebral spinous processes or skull. Here, we have studied the embryonic expression of Msx genes in the European pond turtle, Emys orbicularis. The overall Msx expression in head, limb, and trunk is similar to what is observed in other vertebrates. We have focused on the CR area and pre-skeletal shell condensations. The CR expresses Msx genes transiently, in a pattern similar to that of fgf10. In the future carapace domain, the dermis located dorsal to the spinal cord expresses Msx genes, as in other vertebrates, but we did not see expansion of this expression in the dermis located more laterally, on top of the dermomyotomes. In the ventral plastron, although the dermal osseous condensations form in the embryonic Msx-positive somatopleura, we did not observe enhanced Msx expression around these elements. These observations may indicate that common mechanisms participate in limb bud and CR early development, but that pre-differentiation steps differ between shell and other skeletal structures and involve other gene activities than that of Msx genes.

Expression of the prospective mesoderm genes twist, snail, and mef2 in penaeid shrimp.

PubMed

Wei, Jiankai; Glaves, Richard Samuel Elliot; Sellars, Melony J; Xiang, Jianhai; Hertzler, Philip L

2016-07-01

In penaeid shrimp, mesoderm forms from two sources: naupliar mesoderm founder cells, which invaginate during gastrulation, and posterior mesodermal stem cells called mesoteloblasts, which undergo characteristic teloblastic divisions. The primordial mesoteloblast descends from the ventral mesendoblast, which arrests in cell division at the 32-cell stage and ingresses with its sister dorsal mesendoblast prior to naupliar mesoderm invagination. The naupliar mesoderm forms the muscles of the naupliar appendages (first and second antennae and mandibles), while the mesoteloblasts form the mesoderm, including the muscles, of subsequently formed posterior segments. To better understand the mechanism of mesoderm and muscle formation in penaeid shrimp, twist, snail, and mef2 cDNAs were identified from transcriptomes of Penaeus vannamei, P. japonicus, P. chinensis, and P. monodon. A single Twist ortholog was found, with strong inferred amino acid conservation across all three species. Multiple Snail protein variants were detected, which clustered in a phylogenetic tree with other decapod crustacean Snail sequences. Two closely-related mef2 variants were found in P. vannamei. The developmental mRNA expression of these genes was studied by qPCR in P. vannamei embryos, larvae, and postlarvae. Expression of Pv-twist and Pv-snail began during the limb bud stage and continued through larval stages to the postlarva. Surprisingly, Pv-mef2 expression was found in all stages from the zygote to the postlarva, with the highest expression in the limb bud and protozoeal stages. The results add comparative data on the development of anterior and posterior mesoderm in malacostracan crustaceans, and should stimulate further studies on mesoderm and muscle development in penaeid shrimp.

Fibroblast growth factor signaling in skeletal development and disease

PubMed Central

Ornitz, David M.; Marie, Pierre J.

2015-01-01

Fibroblast growth factor (FGF) signaling pathways are essential regulators of vertebrate skeletal development. FGF signaling regulates development of the limb bud and formation of the mesenchymal condensation and has key roles in regulating chondrogenesis, osteogenesis, and bone and mineral homeostasis. This review updates our review on FGFs in skeletal development published in Genes & Development in 2002, examines progress made on understanding the functions of the FGF signaling pathway during critical stages of skeletogenesis, and explores the mechanisms by which mutations in FGF signaling molecules cause skeletal malformations in humans. Links between FGF signaling pathways and other interacting pathways that are critical for skeletal development and could be exploited to treat genetic diseases and repair bone are also explored. PMID:26220993

Reciprocal Expression of lin-41 and the microRNAs let-7 and mir-125 During Mouse Embryogenesis

PubMed Central

Schulman, Betsy R. Maller; Esquela-Kerscher, Aurora; Slack, Frank J.

2008-01-01

In C. elegans, heterochronic genes control the timing of cell fate determination during development. Two heterochronic genes, let-7 and lin-4, encode microRNAs (miRNAs) that down-regulate a third heterochronic gene lin-41 by binding to complementary sites in its 3’UTR. let-7 and lin-4 are conserved in mammals. Here we report the cloning and sequencing of mammalian lin-41 orthologs. We find that mouse and human lin-41 genes contain predicted conserved complementary sites for let-7 and the lin-4 ortholog, mir-125, in their 3’UTRs. Mouse lin-41 (Mlin-41) is temporally expressed in developing mouse embryos, most dramatically in the limb buds. Mlin-41 is down-regulated during mid-embryogenesis at the time when mouse let-7c and mir-125 RNA levels are up-regulated. Our results suggest that mammalian lin-41 is temporally regulated by miRNAs in order to direct key developmental events such as limb formation. PMID:16247770

Flight feather development: its early specialization during embryogenesis.

PubMed

Kondo, Mao; Sekine, Tomoe; Miyakoshi, Taku; Kitajima, Keiichi; Egawa, Shiro; Seki, Ryohei; Abe, Gembu; Tamura, Koji

2018-01-01

Flight feathers, a type of feather that is unique to extant/extinct birds and some non-avian dinosaurs, are the most evolutionally advanced type of feather. In general, feather types are formed in the second or later generation of feathers at the first and following molting, and the first molting begins at around two weeks post hatching in chicken. However, it has been stated in some previous reports that the first molting from the natal down feathers to the flight feathers is much earlier than that for other feather types, suggesting that flight feather formation starts as an embryonic event. The aim of this study was to determine the inception of flight feather morphogenesis and to identify embryological processes specific to flight feathers in contrast to those of down feathers. We found that the second generation of feather that shows a flight feather-type arrangement has already started developing by chick embryonic day 18, deep in the skin of the flight feather-forming region. This was confirmed by shh gene expression that shows barb pattern, and the expression pattern revealed that the second generation of feather development in the flight feather-forming region seems to start by embryonic day 14. The first stage at which we detected a specific morphology of the feather bud in the flight feather-forming region was embryonic day 11, when internal invagination of the feather bud starts, while the external morphology of the feather bud is radial down-type. The morphogenesis for the flight feather, the most advanced type of feather, has been drastically modified from the beginning of feather morphogenesis, suggesting that early modification of the embryonic morphogenetic process may have played a crucial role in the morphological evolution of this key innovation. Co-optation of molecular cues for axial morphogenesis in limb skeletal development may be able to modify morphogenesis of the feather bud, giving rise to flight feather-specific morphogenesis of traits.

External morphogenesis of the tardigrade Hypsibius dujardini as revealed by scanning electron microscopy.

PubMed

Gross, Vladimir; Minich, Irene; Mayer, Georg

2017-04-01

Tardigrada, commonly called water bears, is a taxon of microscopic panarthropods with five-segmented bodies and four pairs of walking legs. Although tardigrades have been known to science for several centuries, questions remain regarding many aspects of their biology, such as embryogenesis. Herein, we used scanning electron microscopy to document the external changes that occur during embryonic development in the tardigrade Hypsibius dujardini (Eutardigrada, Parachela, Hypsibiidae). Our results show an accelerated development of external features, with approximately 30 hrs separating the point at which external structures first become recognizable and a fully formed embryo. All segments appear to arise simultaneously between ∼20 and 25 hrs of development, and no differences in the degree of development could be detected between the limb buds at any stage. Claws emerge shortly after the limb buds and are morphologically similar to those of adults. The origin of the claws is concurrent with that of the sclerotized parts of the mouth, suggesting that all cuticular structures arise simultaneously at ∼30 hrs. The mouth arises as an invagination in the terminal region of the head at ∼25 hrs, closes later in development, and opens again shortly before hatching. The anlagen of the peribuccal lobes arise as one dorsal and one ventral row, each consisting of three lobes, and later form a ring in the late embryo, whereas there is no indication of a labrum anlage at any point during development. Furthermore, we describe limited postembryonic development in the form of cuticular pores that are absent in juveniles but present in adults. This study represents the first scanning electron micrographs of tardigrade embryos, demonstrating the utility of this technique for studying embryogenesis in tardigrades. This work further adds an external morphological perspective to the developmental data already available for H. dujardini, facilitating future comparisons to related panarthropod taxa. J. Morphol. 278:563-573, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

FT-IR microscopic mappings of early mineralization in chick limb bud mesenchymal cell cultures

NASA Technical Reports Server (NTRS)

Boskey, A. L.; Camacho, N. P.; Mendelsohn, R.; Doty, S. B.; Binderman, I.

1992-01-01

Chick limb bud mesenchymal cells differentiate into chondrocytes and form a cartilaginous matrix in culture. In this study, the mineral formed in different areas within cultures supplemented with 4 mM inorganic phosphate, or 2.5, 5.0, and 10 mM beta-glycerophosphate (beta GP), was characterized by Fourier-transform infrared (FT-IR) microscopy. The relative mineral-to-matrix ratios, and distribution of crystal sizes at specific locations throughout the matrix were measured from day 14 to day 30. The only mineral phase detected was a poorly crystalline apatite. Cultures receiving 4 mM inorganic phosphate had smaller crystals which were less randomly distributed around the cartilage nodules than those in the beta GP-treated cultures. beta GP-induced mineral consisted of larger, more perfect apatite crystals. In cultures receiving 5 or 10 mM beta GP, the relative mineral-to-matrix ratios (calculated from the integrated intensities of the phosphate and amide I bands, respectively) were higher than in the cultures with 4 mM inorganic phosphate or in the in vivo calcified chick cartilage.

Human Mesenchymal Stem Cells Derived From Limb Bud Can Differentiate into All Three Embryonic Germ Layers Lineages

PubMed Central

Jiao, Fei; Wang, Juan; Dong, Zhao-lun; Wu, Min-juan; Zhao, Ting-bao; Li, Dan-dan

2012-01-01

Abstract Mesenchymal stem cells (MSCs) have been isolated from many sources, including adults and fetuses. Previous studies have demonstrated that, compared with their adult counterpart, fetal MSCs with several remarkable advantages may be a better resource for clinical applications. In this study, we successfully isolated a rapidly proliferating cell population from limb bud of aborted fetus and termed them “human limb bud–derived mesenchymal stem cells” (hLB-MSCs). Characteristics of their morphology, phenotype, cell cycle, and differentiation properties were analyzed. These adherent cell populations have a typically spindle-shaped morphology. Flow cytometry analysis showed that hLB-MSCs are positive for CD13, CD29, CD90, CD105, and CD106, but negative for CD3, CD4, CD5, CD11b, CD14, CD15, CD34, CD45, CD45RA, and HLA-DR. The detection of cell cycle from different passages indicated that hLB-MSCs have a similar potential for propagation during long culture in vitro. The most novel finding here is that, in addition to their mesodermal differentiation (osteoblasts and adipocytes), hLB-MSCs can also differentiated into extramesenchymal lineages, such as neural (ectoderm) and hepatic (endoderm) progenies. These results indicate that hLB-MSCs have a high level of plasticity and can differentiate into cell lineages from all three embryonic layers in vitro. PMID:22775353

Nervous systems in 3D: a comparison of Caridean, anomuran, and brachyuran zoea-I (Decapoda).

PubMed

Geiselbrecht, Hannes; Melzer, Roland R

2013-12-01

Using serial semi-thin sections and digital 3D-reconstructions we studied the nervous systems of zoea-I larvae in three decapod species, Hippolyte inermis (Leach, 1815), Porcellana platycheles (Pennant, 1777), and Pachygrapsus marmoratus (Fabricius, 1787). These taxa represent three decapod lineages, that is, Caridea, Anomura, and Brachyura, each characterized by specific zoea-I morphology. Special attention was paid to development of ganglia, neuropil composition, and segmental nerves. In all zoeae studied, the overall elements, for example, the segmental ganglia, their neuropils and most of the nerves of the adult decapod nervous system are present. Ongoing differentiation processes are observable as well, most obvious in segments with well-developed limbs the ganglia are in a more advanced stage of differentiation and more voluminous compared to segments with only limb buds or without externally visible limb anlagen. Intra- and interspecific comparisons indicate that neuromere differentiation thus deviates from a simple anterior-posterior gradient as, for example, posterior thoracic neuromeres are less developed than those of the pleon. In addition, the differences in the progress of the development of ganglia between the studied taxa can best be attributed to heterochronic mechanisms. Taxon and stage-specific morphologies indicate that neuronal architecture reflects both, morphogenesis to the adult stage and specific larval adaptions, and provides sets of characters relevant to understanding the corresponding phylogeny. © 2013 Wiley Periodicals, Inc.

The HoxD cluster is a dynamic and resilient TAD boundary controlling the segregation of antagonistic regulatory landscapes

PubMed Central

Rodríguez-Carballo, Eddie; Lopez-Delisle, Lucille; Zhan, Ye; Fabre, Pierre J.; Beccari, Leonardo; El-Idrissi, Imane; Huynh, Thi Hanh Nguyen; Ozadam, Hakan; Dekker, Job; Duboule, Denis

2017-01-01

The mammalian HoxD cluster lies between two topologically associating domains (TADs) matching distinct enhancer-rich regulatory landscapes. During limb development, the telomeric TAD controls the early transcription of Hoxd genes in forearm cells, whereas the centromeric TAD subsequently regulates more posterior Hoxd genes in digit cells. Therefore, the TAD boundary prevents the terminal Hoxd13 gene from responding to forearm enhancers, thereby allowing proper limb patterning. To assess the nature and function of this CTCF-rich DNA region in embryos, we compared chromatin interaction profiles between proximal and distal limb bud cells isolated from mutant stocks where various parts of this boundary region were removed. The resulting progressive release in boundary effect triggered inter-TAD contacts, favored by the activity of the newly accessed enhancers. However, the boundary was highly resilient, and only a 400-kb deletion, including the whole-gene cluster, was eventually able to merge the neighboring TADs into a single structure. In this unified TAD, both proximal and distal limb enhancers nevertheless continued to work independently over a targeted transgenic reporter construct. We propose that the whole HoxD cluster is a dynamic TAD border and that the exact boundary position varies depending on both the transcriptional status and the developmental context. PMID:29273679

Fibroblast growth factor signaling in skeletal development and disease.

PubMed

Ornitz, David M; Marie, Pierre J

2015-07-15

Fibroblast growth factor (FGF) signaling pathways are essential regulators of vertebrate skeletal development. FGF signaling regulates development of the limb bud and formation of the mesenchymal condensation and has key roles in regulating chondrogenesis, osteogenesis, and bone and mineral homeostasis. This review updates our review on FGFs in skeletal development published in Genes & Development in 2002, examines progress made on understanding the functions of the FGF signaling pathway during critical stages of skeletogenesis, and explores the mechanisms by which mutations in FGF signaling molecules cause skeletal malformations in humans. Links between FGF signaling pathways and other interacting pathways that are critical for skeletal development and could be exploited to treat genetic diseases and repair bone are also explored. © 2015 Ornitz and Marie; Published by Cold Spring Harbor Laboratory Press.

Limb-bud and Heart Overexpression Inhibits the Proliferation and Migration of PC3M Cells.

PubMed

Liu, Qicai; Li, Ermao; Huang, Long; Cheng, Minsheng; Li, Li

2018-01-01

Background: The limb-bud and heart gene ( LBH ) was discovered in the early 21st century and is specifically expressed in the mouse embryonic limb and heart development. Increasing evidences have indicated that LBH not only plays an important role in embryo development, it is also closely correlated with the occurance and progression of many tumors. However, its function in prostate cancer (PCa) is still not well understood. Here, we explored the effects of LBH on the proliferation and migration of the PCa cell line PC3M. Methods: LBH expression in tissues and cell lines of PCa was detected by immunohistochemistry and Western blotting. Lentivirus was used to transduct the LBH gene into the PC3M cells. Stable LBH-overexpressing PC3M-LBH cells and PC3M-NC control cells were obtained via puromycin screening. Cell proliferation was examined using the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell cycle distribution and apoptosis rate were investigated using flow cytometry. Cell migration was studied using the Transwell assay. Results: LBH expression level was down-regulated in 3 different PCa cell lines, especially in PC3M cells, compared with the normal prostate epithelial cells(RWPE-1). Cell lines of LBH-upregulated PC3M-LBH and PC3M-NC control were successfully constructed. Significantly increased LBH expression level and decreased cyclin D1 and cyclin E2 expression level was found in PC3M-LBH cells as compared to the PC3M-NC cells. The overexpression of LBH significantly inhibited PC3M cell proliferation in vitro and tumor growth in nude mice. LBH overexpression in PC3M cell, also induced cell cycle G0/G1 phase arrest and decreased the migration of PC3M cells. Conclusions : Our results reveal that LBH expression is down-regulated in the tissue and cell lines of PCa. LBH overexpression inhibits PC3M cell proliferation and tumor growth by inducing cell cycle arrest through down-regulating cyclin D1and cyclin E2 expression. LBH might be a therapeutic target and potential diagnostic marker in PCa.

New developmental evidence supports a homeotic frameshift of digit identity in the evolution of the bird wing

PubMed Central

2014-01-01

Background The homology of the digits in the bird wing is a high-profile controversy in developmental and evolutionary biology. The embryonic position of the digits cartilages with respect to the primary axis (ulnare and ulna) corresponds to 2, 3, 4, but comparative-evolutionary morphology supports 1, 2, 3. A homeotic frameshift of digit identity in evolution could explain how cells in embryonic positions 2, 3, 4 began developing morphologies 1, 2, 3. Another alternative is that no re-patterning of cell fates occurred, and the primary axis shifted its position by some other mechanism. In the wing, only the anterior digit lacks expression of HoxD10 and HoxD12, resembling digit 1 of other limbs, as predicted by 1, 2, 3. However, upon loss of digit 1 in evolution, the most anterior digit 2 could have lost their expression, deceitfully resembling a digit 1. To test this notion, we observed HoxD10 and HoxD12 in a limb where digit 2 is the most anterior digit: The rabbit foot. We also explored whether early inhibition of Shh signalling in the embryonic wing bud induces an experimental homeotic frameshift, or an experimental axis shift. We tested these hypotheses using DiI injections to study the fate of cells in these experimental wings. Results We found strong transcription of HoxD10 and HoxD12 was present in the most anterior digit 2 of the rabbit foot. Thus, we found no evidence to question the use of HoxD expression as support for 1, 2, 3. When Shh signalling in early wing buds is inhibited, our fate maps demonstrate that an experimental homeotic frameshift is induced. Conclusion Along with comparative morphology, HoxD expression provides strong support for 1, 2, 3 identity of wing digits. As an explanation for the offset 2, 3, 4 embryological position, the homeotic frameshift hypothesis is consistent with known mechanisms of limb development, and further proven to be experimentally possible. In contrast, the underlying mechanisms and experimental plausibility of an axis shift remain unclear. PMID:24725625

New developmental evidence supports a homeotic frameshift of digit identity in the evolution of the bird wing.

PubMed

Salinas-Saavedra, Miguel; Gonzalez-Cabrera, Cristian; Ossa-Fuentes, Luis; Botelho, Joao F; Ruiz-Flores, Macarena; Vargas, Alexander O

2014-04-12

The homology of the digits in the bird wing is a high-profile controversy in developmental and evolutionary biology. The embryonic position of the digits cartilages with respect to the primary axis (ulnare and ulna) corresponds to 2, 3, 4, but comparative-evolutionary morphology supports 1, 2, 3. A homeotic frameshift of digit identity in evolution could explain how cells in embryonic positions 2, 3, 4 began developing morphologies 1, 2, 3. Another alternative is that no re-patterning of cell fates occurred, and the primary axis shifted its position by some other mechanism. In the wing, only the anterior digit lacks expression of HoxD10 and HoxD12, resembling digit 1 of other limbs, as predicted by 1, 2, 3. However, upon loss of digit 1 in evolution, the most anterior digit 2 could have lost their expression, deceitfully resembling a digit 1. To test this notion, we observed HoxD10 and HoxD12 in a limb where digit 2 is the most anterior digit: The rabbit foot. We also explored whether early inhibition of Shh signalling in the embryonic wing bud induces an experimental homeotic frameshift, or an experimental axis shift. We tested these hypotheses using DiI injections to study the fate of cells in these experimental wings. We found strong transcription of HoxD10 and HoxD12 was present in the most anterior digit 2 of the rabbit foot. Thus, we found no evidence to question the use of HoxD expression as support for 1, 2, 3. When Shh signalling in early wing buds is inhibited, our fate maps demonstrate that an experimental homeotic frameshift is induced. Along with comparative morphology, HoxD expression provides strong support for 1, 2, 3 identity of wing digits. As an explanation for the offset 2, 3, 4 embryological position, the homeotic frameshift hypothesis is consistent with known mechanisms of limb development, and further proven to be experimentally possible. In contrast, the underlying mechanisms and experimental plausibility of an axis shift remain unclear.

Ontogeny of the Human Pelvis.

PubMed

Verbruggen, Stefaan W; Nowlan, Niamh C

2017-04-01

The human pelvis has evolved over time into a remarkable structure, optimised into an intricate architecture that transfers the entire load of the upper body into the lower limbs, while also facilitating bipedal movement. The pelvic girdle is composed of two hip bones, os coxae, themselves each formed from the gradual fusion of the ischium, ilium and pubis bones. Unlike the development of the classical long bones, a complex timeline of events must occur in order for the pelvis to arise from the embryonic limb buds. An initial blastemal structure forms from the mesenchyme, with chondrification of this mass leading to the first recognisable elements of the pelvis. Primary ossification centres initiate in utero, followed post-natally by secondary ossification at a range of locations, with these processes not complete until adulthood. This cascade of events can vary between individuals, with recent evidence suggesting that fetal activity can affect the normal development of the pelvis. This review surveys the current literature on the ontogeny of the human pelvis. Anat Rec, 300:643-652, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Effects on in Vivo and in Vitro Exposure to Excess Gravity on Growth and Differentiation of Mammalian Embryos

NASA Technical Reports Server (NTRS)

Duke, J.

1985-01-01

Studies on the development of embryonic mouse tissues exposed to excess gravity in vitro and in vivo are discussed. Suppression is seen in limb buds cultured under 3G. Mouse palates were exposed to excess G in vitro, 13- and 14-day palates were exposed to 2.6G for 24 hours. For in vivo studies, a small animal centrifuge was constructed. When the centrifuge is operated at 40 and 45 rpm, the linear accelerations generated range from 1.8 to 3.5G. The effects of gravity on body weights and on reproduction is also presented.

Congenital anomalies of the hand. The Asian perspective.

PubMed

Ogino, T

1996-02-01

To have a better understanding of teratogenic mechanisms of congenital absence of digits, ulnar and radial deficiencies, cleft hand, and symbrachydactyly were analyzed in clinical cases. The same anomalies were induced in rat fetuses by busulfan, and their characteristics were investigated. The formation process of longitudinal deficiency also was observed histologically. There seemed to be 4 teratogenic mechanisms of congenital absence of digits. Ulnar and radial deficiencies have the same clinical features, and the cause of these deficiencies is related closely to a deficit of mesenchymal cells in the limb bud caused by the impairment before the formation of the limb bud. Cleft hand, central polydactyly, and osseous syndactyly were induced by the same treatment at the same developmental stage in rats. Cleft hand formation process from osseous syndactylies and central polydactylies was supposed. The teratogenic mechanism of cleft hand seemed to be failure of induction of digital rays in the hand plate. The sequence of anomalies from brachysyndactyly, or the atypical cleft hand, to the transverse deficiency can be regarded as equivalent to the category of bony dysplasia of the hand. Congenital constriction ring syndrome does appear after the formation of the digital rays.

Clinical features and teratogenic mechanisms of congenital absence of digits.

PubMed

Ogino, Toshihiko

2007-08-01

To have a better understanding of classification of congenital hand anomalies, clinical features and teratogenic mechanisms of congenital absence of digits including ulnar and radial deficiencies, cleft hand, symbrachydactyly and constriction band were reviewed. There seemed to be four different teratogenic mechanisms of congenital absence of digits. Ulnar and radial deficiencies have the same clinical features and the cause of these deficiencies is closely related to a deficit of mesenchymal cells in the limb-bud due to impairment before the formation of the limb-bud. Cleft hand, central polydactyly and osseous syndactyly were induced by the same treatment at the same developmental stage in rats. Roentgenograms of the clinical cases and skeletal changes of the anomalies in rats appear to demonstrate that cleft hand formation proceeds from osseous syndactylies and central polydactylies. The teratogenic mechanism of a cleft hand seemed to be failure of induction of digital rays in the hand plate. The sequence of anomalies from brachysyndactyly, or the atypical cleft hand, to the congenital amputation, can be regarded as equivalent to the category of transverse deficiency that is bony dysplasia of the hand. Congenital constriction ring syndrome appears after the formation of the digital rays.

The HoxD cluster is a dynamic and resilient TAD boundary controlling the segregation of antagonistic regulatory landscapes.

PubMed

Rodríguez-Carballo, Eddie; Lopez-Delisle, Lucille; Zhan, Ye; Fabre, Pierre J; Beccari, Leonardo; El-Idrissi, Imane; Huynh, Thi Hanh Nguyen; Ozadam, Hakan; Dekker, Job; Duboule, Denis

2017-11-15

The mammalian HoxD cluster lies between two topologically associating domains (TADs) matching distinct enhancer-rich regulatory landscapes. During limb development, the telomeric TAD controls the early transcription of Hoxd genes in forearm cells, whereas the centromeric TAD subsequently regulates more posterior Hoxd genes in digit cells. Therefore, the TAD boundary prevents the terminal Hoxd13 gene from responding to forearm enhancers, thereby allowing proper limb patterning. To assess the nature and function of this CTCF-rich DNA region in embryos , we compared chromatin interaction profiles between proximal and distal limb bud cells isolated from mutant stocks where various parts of this boundary region were removed. The resulting progressive release in boundary effect triggered inter-TAD contacts, favored by the activity of the newly accessed enhancers. However, the boundary was highly resilient, and only a 400-kb deletion, including the whole-gene cluster, was eventually able to merge the neighboring TADs into a single structure. In this unified TAD, both proximal and distal limb enhancers nevertheless continued to work independently over a targeted transgenic reporter construct. We propose that the whole HoxD cluster is a dynamic TAD border and that the exact boundary position varies depending on both the transcriptional status and the developmental context. © 2017 Rodríguez-Carballo et al.; Published by Cold Spring Harbor Laboratory Press.

Positional information is reprogrammed in blastema cells of the regenerating limb of the axolotl (Ambystoma mexicanum).

PubMed

McCusker, Catherine D; Gardiner, David M

2013-01-01

The regenerating region of an amputated salamander limb, known as the blastema, has the amazing capacity to replace exactly the missing structures. By grafting cells from different stages and regions of blastemas induced to form on donor animals expressing Green Fluorescent Protein (GFP), to non-GFP host animals, we have determined that the cells from early stage blastemas, as well as cells at the tip of late stage blastemas are developmentally labile such that their positional identity is reprogrammed by interactions with more proximal cells with stable positional information. In contrast, cells from the adjacent, more proximal stump tissues as well as the basal region of late bud blastemas are positionally stable, and thus form ectopic limb structures when grafted. Finally, we have found that a nerve is required to maintain the blastema cells in a positionally labile state, thus indicating a role for reprogramming cues in the blastema microenvironment.

Molecular events of apical bud formation in white spruce, Picea glauca.

PubMed

El Kayal, Walid; Allen, Carmen C G; Ju, Chelsea J-T; Adams, Eri; King-Jones, Susanne; Zaharia, L Irina; Abrams, Suzanne R; Cooke, Janice E K

2011-03-01

Bud formation is an adaptive trait that temperate forest trees have acquired to facilitate seasonal synchronization. We have characterized transcriptome-level changes that occur during bud formation of white spruce [Picea glauca (Moench) Voss], a primarily determinate species in which preformed stem units contained within the apical bud constitute most of next season's growth. Microarray analysis identified 4460 differentially expressed sequences in shoot tips during short day-induced bud formation. Cluster analysis revealed distinct temporal patterns of expression, and functional classification of genes in these clusters implied molecular processes that coincide with anatomical changes occurring in the developing bud. Comparing expression profiles in developing buds under long day and short day conditions identified possible photoperiod-responsive genes that may not be essential for bud development. Several genes putatively associated with hormone signalling were identified, and hormone quantification revealed distinct profiles for abscisic acid (ABA), cytokinins, auxin and their metabolites that can be related to morphological changes to the bud. Comparison of gene expression profiles during bud formation in different tissues revealed 108 genes that are differentially expressed only in developing buds and show greater transcript abundance in developing buds than other tissues. These findings provide a temporal roadmap of bud formation in white spruce. © 2011 Blackwell Publishing Ltd.

The embryonic origin of the ampullate silk glands of the spider Cupiennius salei.

PubMed

Hilbrant, Maarten; Damen, Wim G M

2015-05-01

Silk production in spiders is considered a key innovation, and to have been vital for the diversification of the clade. The evolutionary origin of the organs involved in spider silk production, however, and in particular of the silk glands, is poorly understood. Homologies have been proposed between these and other glands found in arachnids, but lacking knowledge of the embryonic development of spider silk glands hampers an evaluation of hypotheses. This study focuses on the embryonic origin of the largest silk glands of the spider Cupiennius salei, the major and minor ampullate glands. We show how the ampullate glands originate from ectodermal invaginations on the embryonic spinneret limb buds, in relation to morphogenesis of these buds. Moreover, we visualize the subsequent growth of the ampullate glands in sections of the early postembryonic stages. The invaginations are shown to correlate with expression of the proneural gene CsASH2, which is remarkable since it has been proposed that spider silk glands and their nozzles originate from sensory bristles. Hence, by confirming the ectodermal origin of spider silk glands, and by describing the (post-)embryonic morphogenesis of the ampullate glands, this work provides a starting point for further investigating into the genetic program that underlies their development. Copyright © 2015 Elsevier Ltd. All rights reserved.

Morphological Variation in Anuran Limbs: Constraints and Novelties.

PubMed

Fabrezi, Marissa; Goldberg, Javier; Chuliver Pereyra, Mariana

2017-09-01

Anurans have three primary types of locomotion: walking, jumping, and swimming. Additionally, they may dig, climb, grasp, etc. All adult anurans have four limbs, with four fingers on the hands and five toes on the feet. We summarized and updated knowledge on the interspecific variation within anuran limbs, then discuss how developmental constraints (e.g., in size) and novelties may have influenced anuran diversification through the locomotion. We analyze morphological variation from limb bud stages up to the final limb form resulting from certain skeletal organization and growth. We find limited morphometric variations in the skeleton of different developmental modules (i.e., skull, trunk, urostyle, limbs) indicate that the anuran body shape is largely constrained. We identify specializations of the stylopodium, zeugopodium, and proximal carpals/tarsals that have evolved to facilitiate saltatorial locomotion. We show that the anuran prepollex and prehallux are not vestigial digits and that they have come to serve specialized function. Medial rotation of the manus in anurans appears to have evolved to help distribute the force of impact upon landing at the end of a jump. Additional skeletal elements in anuran limbs are intercalary elements and sesamoids. The intercalary elements appear within neobatrachians and are integrated with digital pads in lineages capable of locomotion on smooth vertical surfaces. They have allowed arboreal anurans to occupy a wide range of arboreal habitats. © 2017 Wiley Periodicals, Inc.

Taste bud cell dynamics during normal and sodium-restricted development.

PubMed

Hendricks, Susan J; Brunjes, Peter C; Hill, David L

2004-04-26

Taste bud volume increases over the postnatal period to match the number of neurons providing innervation. To clarify age-related changes in fungiform taste bud volume, the current study investigated developmental changes in taste bud cell number, proliferation rate, and life span. Taste bud growth can largely be accounted for by addition of cytokeratin-19-positive taste bud cells. Examination of taste bud cell kinetics with 3H-thymidine autoradiography revealed that cell life span and turnover periods were not altered during normal development but that cells were produced more rapidly in young rats, a prominent modification that could lead to increased taste bud size. By comparison, dietary sodium restriction instituted during pre- and postnatal development results in small taste buds at adulthood as a result of fewer cytokeratin-19-positive cells. The dietary manipulation also had profound influences on taste bud growth kinetics, including an increased latency for cells to enter the taste bud and longer life span and turnover periods. These studies provide fundamental, new information about taste bud development under normal conditions and after environmental manipulations that impact nerve/target matching. Copyright 2004 Wiley-Liss, Inc.

Requirement of vitamin C for cartilage calcification in a differentiating chick limb-bud mesenchymal cell culture.

PubMed

Boskey, A L; Stiner, D; Doty, S B; Binderman, I

1991-01-01

Mesenchymal cells isolated from stage 21-24 chick limb-buds plated in a micro-mass culture differentiate to form chondrocytes and synthesize a calcifiable matrix. In the presence of inorganic phosphate (4 mM), hydroxyapatite mineral deposits around cartilage nodules. Ascorbic acid is, in general, an essential co-factor for extracellular matrix synthesis in culture, since it is required for collagen synthesis. In this study we demonstrate that in the absence of ascorbic acid supplementation in the mesenchymal cell cultures, mineral deposition (indicated by X-ray diffraction, measurement of Ca:hydroxyproline ratio, and 45Ca uptake) does not occur. Concentrations of 10-50 micrograms/ml ascorbate were compared to find the "optimal" concentration for cell mediated mineralization; 25 micrograms/ml was selected as optimal based on matrix appearance at the EM level and the rate of 45Ca uptake. High concentrations of ascorbic acid (greater than 75 micrograms/ml), while increasing the amount of hydroxyproline in the matrix synthesized, caused some cell death and hence less cell-mediated mineralization. This study demonstrates both the need for viable cells and a proper matrix for in vitro cell-mediated mineralization, and shows that varying the concentration of L-ascorbate (vitamin C) in the medium can have a marked effect on mineralization in vitro.

Taste bud development and patterning in sighted and blind morphs of Astyanax mexicanus.

PubMed

Varatharasan, Nirupa; Croll, Roger P; Franz-Odendaal, Tamara

2009-12-01

In the blind cave-dwelling morph of A. mexicanus, the eye degenerates while other sensory systems, such as gustation, are expanded compared to their sighted (surface-dwelling) ancestor. This study compares the development of taste buds along the jaws of each morph. To determine whether cavefish have an altered onset or rate of taste bud development, we fluorescently labeled basal and receptor cells within taste buds over a developmental series. Our results show that taste bud number increases during development in both morphs. The rate of development is, however, accelerated in cavefish; a small difference in taste bud number exists at 5 dpf reaching threefold by 22 dpf. The expansion of taste buds in cavefish is, therefore, detectable after the onset of eye degeneration. This study provides important insights into the timing of taste bud expansion in cavefish as well as enhances our understanding of taste bud development in teleosts in general. (c) 2009 Wiley-Liss, Inc.

During development intense Sox2 expression marks not only Prox1-expressing taste bud cell but also perigemmal cell lineages.

PubMed

Nakayama, Ayumi; Miura, Hirohito; Ooki, Makoto; Harada, Shuitsu

2015-03-01

Sox2 is proposed to regulate the differentiation of bipotential progenitor cells into taste bud cells. However, detailed expression of Sox2 remains unclear. In this report, Sox2 expression during taste bud development in the fungiform (FF), circumvallate (CV) and soft palate (SP) areas is examined together with Prox1. First, we immunohistochemically checked Prox1 expression in adults and found that almost all taste bud cells are Prox1-positive. During FF development, intense Sox2 expression was restricted to taste bud primordia expressing Prox1 at E12.5. However, at E14.5, Sox2 was intensely expressed outside the developing taste buds resolving to perigemmal Sox2 expression in adults. In the SP, at E14.5, taste bud primordia emerged as Prox1-expressing cell clusters. However, intense Sox2 expression was not restricted to taste bud primordia but was detected widely in the epithelium. During development, Sox2 expression outside developing taste buds was generally down-regulated but was retained in the perigemmal region similarly to that in the FF. In the CV, the initial stage of taste bud development remained unclear because of the lack of taste bud primordia comparable to that in the FF and SP. Here, we show that Prox1-expressing cells appear in the apical epithelium at E12.5, in the inner trench wall at E17.5 and in the outer trench wall at E18.5. Sox2 was again not restricted to developing taste bud cells expressing Prox1 during CV development. The expression patterns support that Sox2 does not serve as a cell fate selector between taste bud cells and surrounding keratinocytes but rather may contribute to them both.

Duplications of BHLHA9 are associated with ectrodactyly and tibia hemimelia inherited in non-Mendelian fashion.

PubMed

Klopocki, Eva; Lohan, Silke; Doelken, Sandra C; Stricker, Sigmar; Ockeloen, Charlotte W; Soares Thiele de Aguiar, Renata; Lezirovitz, Karina; Mingroni Netto, Regina Celia; Jamsheer, Aleksander; Shah, Hitesh; Kurth, Ingo; Habenicht, Rolf; Warman, Matthew; Devriendt, Koenraad; Kordass, Ulrike; Hempel, Maja; Rajab, Anna; Mäkitie, Outi; Naveed, Mohammed; Radhakrishna, Uppala; Antonarakis, Stylianos E; Horn, Denise; Mundlos, Stefan

2012-02-01

Split-hand/foot malformation (SHFM)-also known as ectrodactyly-is a congenital disorder characterised by severe malformations of the distal limbs affecting the central rays of hands and/or feet. A distinct entity termed SHFLD presents with SHFM and long bone deficiency. Mouse models suggest that a defect of the central apical ectodermal ridge leads to the phenotype. Although six different loci/mutations (SHFM1-6) have been associated with SHFM, the underlying cause in a large number of cases is still unresolved. High resolution array comparative genomic hybridisation (CGH) was performed in patients with SHFLD to detect copy number changes. Candidate genes were further evaluated for expression and function during limb development by whole mount in situ hybridisation and morpholino knock-down experiments. Array CGH showed microduplications on chromosome 17p13.3, a locus previously associated with SHFLD. Detailed analysis of 17 families revealed that this copy number variation serves as a susceptibility factor for a highly variable phenotype with reduced penetrance, particularly in females. Compared to other known causes for SHFLD 17p duplications appear to be the most frequent cause of SHFLD. A ~11.8 kb minimal critical region was identified encompassing a single gene, BHLHA9, a putative basic loop helix transcription factor. Whole mount in situ hybridisation showed expression restricted to the limb bud mesenchyme underlying the apical ectodermal ridge in mouse and zebrafish embryos. Knock down of bhlha9 in zebrafish resulted in shortening of the pectoral fins. Genomic duplications encompassing BHLHA9 are associated with SHFLD and non-Mendelian inheritance characterised by a high degree of non-penetrance with sex bias. Knock-down of bhlha9 in zebrafish causes severe reduction defects of the pectoral fin, indicating a role for this gene in limb development.

The Unique Dorsal Brood Pouch of Thermosbaenacea (Crustacea, Malacostraca) and Description of an Advanced Developmental Stage of Tulumella unidens from the Yucatan Peninsula (Mexico), with a Discussion of Mouth Part Homologies to Other Malacostraca

PubMed Central

Olesen, Jørgen; Boesgaard, Tom; Iliffe, Thomas M.

2015-01-01

The Thermosbaenacea, a small taxon of crustaceans inhabiting subterranean waters, are unique among malacostracans as they brood their offspring dorsally under the carapace. This habit is of evolutionary interest but the last detailed report on thermosbaenacean development is more than 40 years old. Here we provide new observations on an ovigerous female of Tulumella unidens with advanced developmental stages in its brood chamber collected from an anchialine cave at the Yucatan Peninsula, which is only the third report on developmental stages of Thermosbaenacea and the first for the genus Tulumella. Significant in a wider crustacean context, we report and discuss hitherto unexplored lobate structures inside the brood chamber of the female originating at the first (maxilliped) and second thoracic segments, which are most likely modified epipods, perhaps serving as gills. At the posterior margin of carapace of the female are rows of large spines preventing the developing stages from falling out. The external morphology of the advanced developmental stages is described in much detail, providing information on e.g., carapace formation and early limb morphology. Among the hitherto unknown structures in the advanced developmental stages provided by this study are the presence of an embryonic dorsal organ and rudimentary ‘naupliar processes’ of the second antennae. Since most hypotheses on crustacean (and malacostracan and peracaridan) relationship rest on external limb morphology, we use early limb bud morphology of Tulumella to better establish thermosbaenacean limb homologies to those of other crustaceans, which is a necessary basis for future morphology based phylogenetic considerations. PMID:25901753

The Unique Dorsal Brood Pouch of Thermosbaenacea (Crustacea, Malacostraca) and Description of an Advanced Developmental Stage of Tulumella unidens from the Yucatan Peninsula (Mexico), with a Discussion of Mouth Part Homologies to Other Malacostraca.

PubMed

Olesen, Jørgen; Boesgaard, Tom; Iliffe, Thomas M

2015-01-01

The Thermosbaenacea, a small taxon of crustaceans inhabiting subterranean waters, are unique among malacostracans as they brood their offspring dorsally under the carapace. This habit is of evolutionary interest but the last detailed report on thermosbaenacean development is more than 40 years old. Here we provide new observations on an ovigerous female of Tulumella unidens with advanced developmental stages in its brood chamber collected from an anchialine cave at the Yucatan Peninsula, which is only the third report on developmental stages of Thermosbaenacea and the first for the genus Tulumella. Significant in a wider crustacean context, we report and discuss hitherto unexplored lobate structures inside the brood chamber of the female originating at the first (maxilliped) and second thoracic segments, which are most likely modified epipods, perhaps serving as gills. At the posterior margin of carapace of the female are rows of large spines preventing the developing stages from falling out. The external morphology of the advanced developmental stages is described in much detail, providing information on e.g., carapace formation and early limb morphology. Among the hitherto unknown structures in the advanced developmental stages provided by this study are the presence of an embryonic dorsal organ and rudimentary 'naupliar processes' of the second antennae. Since most hypotheses on crustacean (and malacostracan and peracaridan) relationship rest on external limb morphology, we use early limb bud morphology of Tulumella to better establish thermosbaenacean limb homologies to those of other crustaceans, which is a necessary basis for future morphology based phylogenetic considerations.

Effect of alternating day and night temperature on short day-induced bud set and subsequent bud burst in long days in Norway spruce

PubMed Central

Olsen, Jorunn E.; Lee, YeonKyeong; Junttila, Olavi

2014-01-01

Young seedlings of the conifer Norway spruce exhibit short day (SD)-induced cessation of apical growth and bud set. Although different, constant temperatures under SD are known to modulate timing of bud set and depth of dormancy with development of deeper dormancy under higher compared to lower temperature, systematic studies of effects of alternating day (DT) and night temperatures (NT) are limited. To shed light on this, seedlings of different provenances of Norway spruce were exposed to a wide range of DT-NT combinations during bud development, followed by transfer to forcing conditions of long days (LD) and 18°C, directly or after different periods of chilling. Although no specific effect of alternating DT/NT was found, the results demonstrate that the effects of DT under SD on bud set and subsequent bud break are significantly modified by NT in a complex way. The effects on bud break persisted after chilling. Since time to bud set correlated with the daily mean temperature under SD at DTs of 18 and 21°C, but not a DT of 15°C, time to bud set apparently also depend on the specific DT, implying that the effect of NT depends on the actual DT. Although higher temperature under SD generally results in later bud break after transfer to forcing conditions, the fastest bud flush was observed at intermediate NTs. This might be due to a bud break-hastening chilling effect of intermediate compared to higher temperatures, and delayed bud development to a stage where bud burst can occur, under lower temperatures. Also, time to bud burst in un-chilled seedlings decreased with increasing SD-duration, suggesting that bud development must reach a certain stage before the processes leading to bud burst are initiated. The present results also indicate that low temperature during bud development had a larger effect on the most southern compared to the most northern provenance studied. Decreasing time to bud burst was observed with increasing northern latitude of origin in un-chilled as well as chilled plants. In conclusion, being a highly temperature-dependent process, bud development is strongly delayed by low temperature, and the effects of DT is significantly modified by NT in a complex manner. PMID:25538722

Innervation of single fungiform taste buds during development in rat.

PubMed

Krimm, R F; Hill, D L

1998-08-17

To determine whether the innervation of taste buds changes during postnatal development, the number of geniculate ganglion cells that innervated single fungiform taste buds were quantified in the tip- and midregions of the tongue of adult and developing rats. There was substantial variation in both the size of individual taste buds and number of geniculate ganglion cells that innervated them. Importantly, taste bud morphology and innervation were highly related. Namely, the number of labeled geniculate ganglion cells that innervated a taste bud was highly correlated with the size of the taste bud (r = 0.91, P < .0003): The larger the taste bud, the more geniculate ganglion cells that innervated it. The relationship between ganglion cell number and taste bud volume emerged during the first 40 days postnatal. Whereas there was no difference in the average number of ganglion cells that innervated individual taste buds in rats aged 10 days postnatal through adulthood, taste bud volumes increased progressively between 10 and 40 days postnatal, at which age taste bud volumes were similar to adults. The maturation of taste bud size was accompanied by the emergence of the relationship between taste bud volume and number of innervating neurons. Specifically, there was no correlation between taste bud size and number of innervating geniculate ganglion cells in 10-, 20-, or 30-day-old rats, whereas taste bud size and the number of innervating ganglion cells in 40-day-old rats were positively correlated (r = .80, P < .002). Therefore, the relationship between taste bud size and number of innervating ganglion cells develops over a prolonged postnatal period and is established when taste buds grow to their adult size.

Cell tracing reveals a dorsoventral lineage restriction plane in the mouse limb bud mesenchyme.

PubMed

Arques, Carlos G; Doohan, Roisin; Sharpe, James; Torres, Miguel

2007-10-01

Regionalization of embryonic fields into independent units of growth and patterning is a widespread strategy during metazoan development. Compartments represent a particular instance of this regionalization, in which unit coherence is maintained by cell lineage restriction between adjacent regions. Lineage compartments have been described during insect and vertebrate development. Two common characteristics of the compartments described so far are their occurrence in epithelial structures and the presence of signaling regions at compartment borders. Whereas Drosophila compartmental organization represents a background subdivision of embryonic fields that is not necessarily related to anatomical structures, vertebrate compartment borders described thus far coincide with, or anticipate, anatomical or cell-type discontinuities. Here, we describe a general method for clonal analysis in the mouse and use it to determine the topology of clone distribution along the three limb axes. We identify a lineage restriction boundary at the limb mesenchyme dorsoventral border that is unrelated to any anatomical discontinuity, and whose lineage restriction border is not obviously associated with any signaling center. This restriction is the first example in vertebrates of a mechanism of primordium subdivision unrelated to anatomical boundaries. Furthermore, this is the first lineage compartment described within a mesenchymal structure in any organism, suggesting that lineage restrictions are fundamental not only for epithelial structures, but also for mesenchymal field patterning. No lineage compartmentalization was found along the proximodistal or anteroposterior axes, indicating that patterning along these axes does not involve restriction of cell dispersion at specific axial positions.

Dynamics of BMP signaling in limb bud mesenchyme and polydactyly.

PubMed

Norrie, Jacqueline L; Lewandowski, Jordan P; Bouldin, Cortney M; Amarnath, Smita; Li, Qiang; Vokes, Martha S; Ehrlich, Lauren I R; Harfe, Brian D; Vokes, Steven A

2014-09-15

Mutations in the Bone Morphogenetic Protein (BMP) pathway are associated with a range of defects in skeletal formation. Genetic analysis of BMP signaling requirements is complicated by the presence of three partially redundant BMPs that are required for multiple stages of limb development. We generated an inducible allele of a BMP inhibitor, Gremlin, which reduces BMP signaling. We show that BMPs act in a dose and time dependent manner in which early reduction of BMPs result in digit loss, while inhibiting overall BMP signaling between E10.5 and E11.5 allows polydactylous digit formation. During this period, inhibiting BMPs extends the duration of FGF signaling. Sox9 is initially expressed in normal digit ray domains but at reduced levels that correlate with the reduction in BMP signaling. The persistence of elevated FGF signaling likely promotes cell proliferation and survival, inhibiting the activation of Sox9 and secondarily, inhibiting the differentiation of Sox9-expressing chondrocytes. Our results provide new insights into the timing and clarify the mechanisms underlying BMP signaling during digit morphogenesis. Copyright © 2014 Elsevier Inc. All rights reserved.

Sonic hedgehog: restricted expression and limb dysmorphologies

PubMed Central

Hill, Robert E; Heaney, Simon JH; Lettice, Laura A

2003-01-01

Sonic hedgehog, SHH, is required for patterning the limb. The array of skeletal elements that compose the hands and feet, and the ordered arrangement of these bones to form the pattern of fingers and toes are dependent on SHH. The mechanism of action of SHH in the limb is not fully understood; however, an aspect that appears to be important is the localized, asymmetric expression of Shh. Shh is expressed in the posterior margin of the limb bud in a region defined as the zone of polarizing activity (ZPA). Analysis of mouse mutants which have polydactyly (extra toes) shows that asymmetric expression of Shh is lost due to the appearance of an ectopic domain of expression in the anterior limb margin. One such polydactylous mouse mutant, sasquatch (Ssq), maps to the corresponding chromosomal region of the human condition pre-axial polydactyly (PPD) and thus represents a model for this condition. The mutation responsible for Ssq is located 1 Mb away from the Shh gene; however, the mutation disrupts a long-range cis-acting regulator of Shh expression. By inference, human pre-axial polydactyly results from a similar disruption of Shh expression. Other human congenital abnormalities also map near the pre-axial polydactyly locus, suggesting a major chromosomal region for limb dysmorphologies. The distinct phenotypes range from loss of all bones of the hands and feet to syndactyly of the soft tissue and fusion of the digits. We discuss the role played by Shh expression in mouse mutant phenotypes and the human limb dysmorphologies. PMID:12587915

Bud development and hydraulics

PubMed Central

Cochard, Hervé

2008-01-01

The distal zone of one-year-old apple (Malus domestica) shoots was studied on five cultivars for bud size and composition (number of appendages) and hydraulic conductance before bud burst. Our hypothesis was that bud development was related to hydraulic conductance of the sap pathway to the bud independent of an acrotonic (proximal vs. distal) effect. Bud size and composition, and hydraulic conductance, were highly variable for all cultivars. A positive correlation was demonstrated between both the number of cataphylls and green-leaf primordia and hydraulic conductance. Cultivar and bud size affected the intercept of these relationships more than the slope suggesting similar scaling between these variables but different hydraulic efficiencies. A great proportion of small buds were also characterized by null values of hydraulic conductance. Our study suggests that hydraulically mediated competitions exist between adjacent buds within a same branching zone prefiguring the variability of lateral types in the following growing season. It is hypothesized that this developmental patterning is driven by hydraulic characteristics of the whole-metamer, including the subtending leaf, during bud development. PMID:19704779

Transcriptome analysis of Petunia axillaris flowers reveals genes involved in morphological differentiation and metabolite transport

PubMed Central

Amano, Ikuko; Kitajima, Sakihito; Suzuki, Hideyuki; Koeduka, Takao

2018-01-01

The biosynthesis of plant secondary metabolites is associated with morphological and metabolic differentiation. As a consequence, gene expression profiles can change drastically, and primary and secondary metabolites, including intermediate and end-products, move dynamically within and between cells. However, little is known about the molecular mechanisms underlying differentiation and transport mechanisms. In this study, we performed a transcriptome analysis of Petunia axillaris subsp. parodii, which produces various volatiles in its corolla limbs and emits metabolites to attract pollinators. RNA-sequencing from leaves, buds, and limbs identified 53,243 unigenes. Analysis of differentially expressed genes, combined with gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses, showed that many biological processes were highly enriched in limbs. These included catabolic processes and signaling pathways of hormones, such as gibberellins, and metabolic pathways, including phenylpropanoids and fatty acids. Moreover, we identified five transporter genes that showed high expression in limbs, and we performed spatiotemporal expression analyses and homology searches to infer their putative functions. Our systematic analysis provides comprehensive transcriptomic information regarding morphological differentiation and metabolite transport in the Petunia flower and lays the foundation for establishing the specific mechanisms that control secondary metabolite biosynthesis in plants. PMID:29902274

Embryology meets molecular biology: Deciphering the apical ectodermal ridge.

PubMed

Verheyden, Jamie M; Sun, Xin

2017-09-15

More than sixty years ago, while studying feather tracks on the shoulder of the chick embryo, Dr. John Saunders used Nile Blue dye to stain the tissue. There, he noticed a darkly stained line of cells that neatly rims the tip of the growing limb bud. Rather than ignoring this observation, he followed it up by removing this tissue and found that it led to a striking truncation of the limb skeletons. This landmark experiment marks the serendipitous discovery of the apical ectodermal ridge (AER), the quintessential embryonic structure that drives the outgrowth of the limb. Dr. Saunders continued to lead the limb field for the next fifty years, not just through his own work, but also by inspiring the next generation of researchers through his infectious love of science. Together, he and those who followed ushered in the discovery of fibroblast growth factor (FGF) as the AER molecule. The seamless marriage of embryology and molecular biology that led to the decoding of the AER serves as a shining example of how discoveries are made for the rest of the developmental biology field. Copyright © 2017 Elsevier Inc. All rights reserved.

The formation of endoderm-derived taste sensory organs requires a Pax9-dependent expansion of embryonic taste bud progenitor cells.

PubMed

Kist, Ralf; Watson, Michelle; Crosier, Moira; Robinson, Max; Fuchs, Jennifer; Reichelt, Julia; Peters, Heiko

2014-10-01

In mammals, taste buds develop in different regions of the oral cavity. Small epithelial protrusions form fungiform papillae on the ectoderm-derived dorsum of the tongue and contain one or few taste buds, while taste buds in the soft palate develop without distinct papilla structures. In contrast, the endoderm-derived circumvallate and foliate papillae located at the back of the tongue contain a large number of taste buds. These taste buds cluster in deep epithelial trenches, which are generated by intercalating a period of epithelial growth between initial placode formation and conversion of epithelial cells into sensory cells. How epithelial trench formation is genetically regulated during development is largely unknown. Here we show that Pax9 acts upstream of Pax1 and Sox9 in the expanding taste progenitor field of the mouse circumvallate papilla. While a reduced number of taste buds develop in a growth-retarded circumvallate papilla of Pax1 mutant mice, its development arrests completely in Pax9-deficient mice. In addition, the Pax9 mutant circumvallate papilla trenches lack expression of K8 and Prox1 in the taste bud progenitor cells, and gradually differentiate into an epidermal-like epithelium. We also demonstrate that taste placodes of the soft palate develop through a Pax9-dependent induction. Unexpectedly, Pax9 is dispensable for patterning, morphogenesis and maintenance of taste buds that develop in ectoderm-derived fungiform papillae. Collectively, our data reveal an endoderm-specific developmental program for the formation of taste buds and their associated papilla structures. In this pathway, Pax9 is essential to generate a pool of taste bud progenitors and to maintain their competence towards prosensory cell fate induction.

Developmental expression of membrane type 4-matrix metalloproteinase (Mt4-mmp/Mmp17) in the mouse embryo

PubMed Central

Clemente, Cristina; Montalvo, María Gregoria; Seiki, Motoharu; Arroyo, Alicia G.

2017-01-01

Matrix metalloproteinases (MMPs) constitute a large group of endoproteases that play important functions during embryonic development, tumor metastasis and angiogenesis by degrading components of the extracellular matrix. Within this family, we focused our study on Mt4-mmp (also called Mmp17) that belongs to a distinct subset that is anchored to the cell surface via a glycosylphosphatidylinositol (GPI) moiety and with the catalytic site exposed to the extracellular space. Information about its function and substrates is very limited to date, and little has been reported on its role in the developing embryo. Here, we report a detailed expression analysis of Mt4-mmp during mouse embryonic development by using a LacZ reporter transgenic mouse line. We showed that Mt4-mmp is detected from early stages of development to postnatal stages following a dynamic and restricted pattern of expression. Mt4-mmp was first detected at E8.5 limited to the intersomitic vascularization, the endocardial endothelium and the dorsal aorta. Mt4-mmpLacZ/+ cells were also observed in the neural crest cells, somites, floor plate and notochord at early stages. From E10.5, expression localized in the limb buds and persists during limb development. A strong expression in the brain begins at E12.5 and continues to postnatal stages. Specifically, staining was observed in the olfactory bulb, cerebral cortex, hippocampus, striatum, septum, dorsal thalamus and the spinal cord. In addition, LacZ-positive cells were also detected during eye development, initially at the hyaloid artery and later on located in the lens and the neural retina. Mt4-mmp expression was confirmed by quantitative RT-PCR and western blot analysis in some embryonic tissues. Our data point to distinct functions for this metalloproteinase during embryonic development, particularly during brain formation, angiogenesis and limb development. PMID:28926609

Mice embryology: a microscopic overview.

PubMed

Salvadori, Maria Letícia Baptista; Lessa, Thais Borges; Russo, Fabiele Baldino; Fernandes, Renata Avancini; Kfoury, José Roberto; Braga, Patricia Cristina Baleeiro Beltrão; Miglino, Maria Angélica

2012-10-01

In this work, we studied the embryology of mice of 12, 14, and 18 days of gestation by gross observation, light microscopy, and scanning electron microscopy. Grossly, the embryos of 12 days were observed in C-shaped region of the brain, eye pigmentation of the retina, first, second, and third pharyngeal arches gill pit nasal region on the fourth ventricle brain, cervical curvature, heart, liver, limb bud thoracic, spinal cord, tail, umbilical cord, and place of the mesonephric ridge. Microscopically, the liver, cardiovascular system and spinal cord were observed. In the embryo of 14 days, we observed structures that make up the liver and heart. At 18 days of gestation fetuses, it was noted the presence of eyes, mouth, and nose in the cephalic region, chest and pelvic region with the presence of well-developed limbs, umbilical cord, and placenta. Scanning electron microscopy in 18 days of gestation fetuses evidenced head, eyes closed eyelids, nose, vibrissae, forelimb, heart, lung, kidney, liver, small bowel, diaphragm, and part of the spine. The results obtained in this work describe the internal and external morphology of mice, provided by an integration of techniques and review of the morphological knowledge of the embryonic development of this species, as this animal is of great importance to scientific studies. Copyright © 2012 Wiley Periodicals, Inc.

Rac1 Dosage Is Crucial for Normal Endochondral Bone Growth.

PubMed

Suzuki, Dai; Bush, Jason R; Bryce, Dawn-Marie; Kamijo, Ryutaro; Beier, Frank

2017-10-01

Rac1, a member of the small Rho GTPase family, plays multiple cellular roles. Studies of mice conditionally lacking Rac1 have revealed essential roles for Rac1 in various tissues, including cartilage and limb mesenchyme, where Rac1 loss produces dwarfism and long bone shortening. To gain further insight into the role of Rac1 in skeletal development, we have used transgenic mouse lines to express a constitutively active (ca) Rac1 mutant protein in a Cre recombinase-dependent manner. Overexpression of caRac1 in limb bud mesenchyme or chondrocytes leads to reduced body weight and shorter bones compared with control mice. Histological analysis of growth plates showed that caRac1;Col2-Cre mice displayed ectopic hypertrophic chondrocytes in the proliferative zone and enlarged hypertrophic zones. These mice also displayed a reduced proportion of proliferating cell nuclear antigen-positive cells in the proliferative zone and nuclear β-catenin localization in the ectopic hypertrophic chondrocytes. Importantly, overexpression of caRac1 partially rescued the phenotypes of Rac1fl/fl;Col2-Cre and Rac1fl/fl;Prx1-Cre conditional knockout mice, including body weight, bone length, and growth plate disorganization. These results suggest that tight regulation of Rac1 activity is necessary for normal cartilage development. Copyright © 2017 Endocrine Society.

Fetus-in-Fetu: An Unusual Cause for Abdominal Mass in Infancy

PubMed Central

Grosfeld, Jay L.; Stepita, Donald S.; Nance, Walter E.; Palmer, Catherine G.

1974-01-01

Fetus-in-fetu is an unusual cause of retroperitoneal abdominal mass in infants, which most likely arises from inclusion of a monozygotic, diamniotic twin. This entity is distinguished from teratoma by its embryological origin, its unusual location in the retroperitoneal space, its invariable benignity, and by the presence of vertebral organization with limb buds and well-developed organ systems. Diagnosis is made radiographically by the finding of a diminutive vertebral column on a plain abdominal film. The treatment of choice is total excision with special attention being given to the fetus' blood supply which may be directly from the host's superior mesenteric vessels. A well-documented example of this unusual entity that occurred in a six-week old infant male is presented. ImagesFig. 1.Fig. 2.Fig. 3. PMID:4471720

Embryonic development of Python sebae - I: Staging criteria and macroscopic skeletal morphogenesis of the head and limbs.

PubMed

Boughner, Julia C; Buchtová, Marcela; Fu, Katherine; Diewert, Virginia; Hallgrímsson, Benedikt; Richman, Joy M

2007-01-01

This study explores the post-ovipositional craniofacial development of the African Rock Python (Python sebae). We first describe a staging system based on external characteristics and next use whole-mount skeletal staining supplemented with Computed tomography (CT) scanning to examine skeletal development. Our results show that python embryos are in early stages of organogenesis at the time of laying, with separate facial prominences and pharyngeal clefts still visible. Limb buds are also visible. By 11 days (stage 3), the chondrocranium is nearly fully formed; however, few intramembranous bones can be detected. One week later (stage 4), many of the intramembranous upper and lower jaw bones are visible but the calvaria are not present. Skeletal elements in the limbs also begin to form. Between stages 4 (day 18) and 7 (day 44), the complete set of intramembranous bones in the jaws and calvaria develops. Hindlimb development does not progress beyond stage 6 (33 days) and remains rudimentary throughout adult life. In contrast to other reptiles, there are two rows of teeth in the upper jaw. The outer tooth row is attached to the maxillary and premaxillary bones, whereas the inner row is attached to the pterygoid and palatine bones. Erupted teeth can be seen in whole-mount stage 10 specimens and are present in an unerupted, mineralized state at stage 7. Micro-CT analysis reveals that all the young membranous bones can be recognized even out of the context of the skull. These data demonstrate intrinsic patterning of the intramembranous bones, even though they form without a cartilaginous template. In addition, intramembranous bone morphology is established prior to muscle function, which can influence bone shape through differential force application. After careful staging, we conclude that python skeletal development occurs slowly enough to observe in good detail the early stages of craniofacial skeletogenesis. Thus, reptilian animal models will offer unique opportunities for understanding the early influences that contribute to perinatal bone shape.

Constitutive stimulatory G protein activity in limb mesenchyme impairs bone growth.

PubMed

Karaca, Anara; Malladi, Vijayram Reddy; Zhu, Yan; Tafaj, Olta; Paltrinieri, Elena; Wu, Joy Y; He, Qing; Bastepe, Murat

2018-05-01

GNAS mutations leading to constitutively active stimulatory G protein alpha-subunit (Gsα) cause different tumors, fibrous dysplasia of bone, and McCune-Albright syndrome, which are typically not associated with short stature. Enhanced signaling of the parathyroid hormone/parathyroid hormone-related peptide receptor, which couples to multiple G proteins including Gsα, leads to short bones with delayed endochondral ossification. It has remained unknown whether constitutive Gsα activity also impairs bone growth. Here we generated mice expressing a constitutively active Gsα mutant (Gsα-R201H) conditionally upon Cre recombinase (cGsα R201H mice). Gsα-R201H was expressed in cultured bone marrow stromal cells from cGsα R201H mice upon adenoviral-Cre transduction. When crossed with mice in which Cre is expressed in a tamoxifen-regulatable fashion (CAGGCre-ER™), tamoxifen injection resulted in mosaic expression of the transgene in double mutant offspring. We then crossed the cGsα R201H mice with Prx1-Cre mice, in which Cre is expressed in early limb-bud mesenchyme. The double mutant offspring displayed short limbs at birth, with narrow hypertrophic chondrocyte zones in growth plates and delayed formation of secondary ossification center. Consistent with enhanced Gsα signaling, bone marrow stromal cells from these mice demonstrated increased levels of c-fos mRNA. Our findings indicate that constitutive Gsα activity during limb development disrupts endochondral ossification and bone growth. Given that Gsα haploinsufficiency also leads to short bones, as in patients with Albright's hereditary osteodystrophy, these results suggest that a tight control of Gsα activity is essential for normal growth plate physiology. Copyright © 2018 Elsevier Inc. All rights reserved.

In situ hybridization and immunohistochemistry of bone sialoprotein and secreted phosphoprotein 1 (osteopontin) in the developing mouse mandibular condylar cartilage compared with limb bud cartilage

PubMed Central

Shibata, Shunichi; Fukada, Kenji; Suzuki, Shoichi; Ogawa, Takuya; Yamashita, Yasuo

2002-01-01

Mandibular condylar cartilage is often classified as a secondary cartilage, differing from the primary cartilaginous skeleton in its rapid progress from progenitor cells to hypertrophic chondrocytes. In this study we used in situ hybridization and immunohistochemistry to investigate whether the formation of primary (tibial) and secondary (condylar) cartilage also differs with respect to the expression of two major non-collagenous glycoproteins of bone matrix, bone sialoprotein (BSP) and secreted phosphoprotein 1 (Spp1, osteopontin). The mRNAs for both molecules were never expressed until hypertrophic chondrocytes appeared. In the tibial cartilage, hypertrophic chondrocytes first appeared at E14 and the expression of BSP and Spp1 mRNAs was detected in the lower hypertrophic cell zone, but the expression of BSP mRNA was very weak. In the condylar cartilage, hypertrophic chondrocytes appeared at E15 as soon as cartilage tissue appeared. The mRNAs for both molecules were expressed in the newly formed condylar cartilage, although the proteins were not detected by immunostaining; BSP mRNA in the condylar cartilage was more extensively expressed than that in the tibial cartilage at the corresponding stage (first appearance of hypertrophic cell zone). Endochondral bone formation started at E15 in the tibial cartilage and at E16 in the condylar cartilage. At this stage (first appearance of endochondral bone formation), BSP mRNA was also more extensively expressed in the condylar cartilage than in the tibial cartilage. The hypertrophic cell zone in the condylar cartilage rapidly extended during E15–16. These results indicate that the formation process of the mandibular condylar cartilage differs from that of limb bud cartilage with respect to the extensive expression of BSP mRNA and the rapid extension of the hypertrophic cell zone at early stages of cartilage formation. Furthermore, these results support the hypothesis that, in vivo, BSP promotes the initiation of mineralization. PMID:12033735

Genomic regression of claw keratin, taste receptor and light-associated genes provides insights into biology and evolutionary origins of snakes.

PubMed

Emerling, Christopher A

2017-10-01

Regressive evolution of anatomical traits often corresponds with the regression of genomic loci underlying such characters. As such, studying patterns of gene loss can be instrumental in addressing questions of gene function, resolving conflicting results from anatomical studies, and understanding the evolutionary history of clades. The evolutionary origins of snakes involved the regression of a number of anatomical traits, including limbs, taste buds and the visual system, and by analyzing serpent genomes, I was able to test three hypotheses associated with the regression of these features. The first concerns two keratins that are putatively specific to claws. Both genes that encode these keratins are pseudogenized/deleted in snake genomes, providing additional evidence of claw-specificity. The second hypothesis is that snakes lack taste buds, an issue complicated by conflicting results in the literature. I found evidence that different snakes have lost one or more taste receptors, but all snakes examined retained at least one gustatory channel. The final hypothesis addressed is that the earliest snakes were adapted to a dim light niche. I found evidence of deleted and pseudogenized genes with light-associated functions in snakes, demonstrating a pattern of gene loss similar to other dim light-adapted clades. Molecular dating estimates suggest that dim light adaptation preceded the loss of limbs, providing some bearing on interpretations of the ecological origins of snakes. Copyright © 2017 Elsevier Inc. All rights reserved.

Localization of Ulex europaeus agglutinin-I (UEA-I) in the developing gustatory epithelium of the rat.

PubMed

Taniguchi, Ryo; Shi, Lei; Honma, Shiho; Fujii, Masae; Ueda, Katsura; El-Sharaby, Ashraf; Wakisaka, Satoshi

2004-09-01

To understand the development of the gustatory structures necessitates a reliable marker for both immature and mature taste buds. It has been reported that the intragemmal cells within the taste buds of adult rats were bound to Ulex europaeus agglutinin-I (UEA-I), a specific lectin for alpha-linked fucose, but it has not been determined whether immature taste buds, i.e. taste buds without an apparent taste pore, are labeled with UEA-I. The present study was conducted to examine the UEA-I binding pattern during the development of the rat gustatory epithelium. In adult animals, UEA-I bound to the membrane of taste buds in all examined regions of the gustatory epithelium. Within the individual taste buds, UEA-I labeled almost all intragemmal cells. The binding of UEA-I was occasionally detected below the keratinized layer of the trench wall epithelium but could not be found in the lingual epithelium of the adult animal. During the development of circumvallate papilla, some cells within the immature taste buds were also labeled with UEA-I. The developmental changes in the UEA-I binding pattern in fungiform papillae were almost identical to those in the circumvallate papilla: both immature and mature taste buds were labeled with UEA-I. The present results indicate that UEA-I is a specific lectin for the intragemmal cells of both immature and mature taste buds and, thus, UEA-I can be used as a reliable marker for all taste buds in the rat.

Herbivory modifies conifer phenology: induced amelioration by a specialist folivore.

PubMed

Carroll, Allan L; Quiring, Dan T

2003-06-01

Herbivory by Zeiraphera canadensis Mut. & Free. (Lepidoptera: Tortricidae), an early season folivore of white spruce [ Picea glauca(Moench) Voss], has been associated with a shift in the timing of bud burst by its host during the subsequent year. We tested the hypothesis that a herbivory-induced shift in the phenology of bud development improves the window for colonisation of white spruce buds by Z. canadensis. Feeding on cortical tissue of elongating shoots caused the destruction of apical buds and an interruption of apical dominance in the year following herbivory. White spruce compensated for damage with the activation of dormant buds; mainly at proximal positions along shoots. As a result, half of all active buds on previously damaged branches were located immediately adjacent egg sites (i.e. previous year's bud scales), whereas <10% of active buds on intact shoots were situated there. More than 40% of newly emerged larvae colonised the basal buds of damaged shoots versus just 10% for intact shoots. Previous herbivory also influenced the initiation of bud burst. All buds flushed 2 days earlier on damaged shoots and date of bud burst was inversely correlated to bud density, indicating that short damaged shoots with large numbers of buds were stronger sinks for nutrients required for bud development. Egg hatch was best synchronized with early bursting buds on damaged branches. As a consequence, 89% of first-instar larvae successfully colonised buds on damaged branches while only 55% were successful on undamaged branches. Improved survival of larvae in the year following herbivory was a direct result of the evolved response by white spruce to the interruption of apical dominance. The pattern of herbivory by Z. canadensis may have evolved as a strategy to enhance the quality of white spruce for their offspring.

The pleiotropic mouse phenotype extra-toes spotting is caused by translation initiation factor Eif3c mutations and is associated with disrupted sonic hedgehog signaling.

PubMed

Gildea, Derek E; Luetkemeier, Erin S; Bao, Xiaozhong; Loftus, Stacie K; Mackem, Susan; Yang, Yingzi; Pavan, William J; Biesecker, Leslie G

2011-05-01

Polydactyly is a common malformation and can be an isolated anomaly or part of a pleiotropic syndrome. The elucidation of the mutated genes that cause polydactyly provides insight into limb development pathways. The extra-toes spotting (Xs) mouse phenotype manifests anterior polydactyly, predominantly in the forelimbs, with ventral hypopigmenation. The mapping of Xs(J) to chromosome 7 was confirmed, and the interval was narrowed to 322 kb using intersubspecific crosses. Two mutations were identified in eukaryotic translation initiation factor 3 subunit C (Eif3c). An Eif3c c.907C>T mutation (p.Arg303X) was identified in Xs(J), and a c.1702_1758del mutation (p.Leu568_Leu586del) was identified in extra-toes spotting-like (Xsl), an allele of Xs(J). The effect of the Xs(J) mutation on the SHH/GLI3 pathway was analyzed by in situ hybridization analysis, and we show that Xs mouse embryos have ectopic Shh and Ptch1 expression in the anterior limb. In addition, anterior limb buds show aberrant Gli3 processing, consistent with perturbed SHH/GLI3 signaling. Based on the occurrence of Eif3c mutations in 2 Xs lines and haploinsufficiency of the Xs(J) allele, we conclude that the Xs phenotype is caused by a mutation in Eif3c, a component of the translation initiation complex, and that the phenotype is associated with aberrant SHH/GLI3 signaling.

The ultrastructure of book lung development in the bark scorpion Centruroides gracilis (Scorpiones: Buthidae)

PubMed Central

2011-01-01

Background Near the end of the nineteenth century the hypothesis was presented for the homology of book lungs in arachnids and book gills in the horseshoe crab. Early studies with the light microscope showed that book gill lamellae are formed by outgrowth and possibly some invagination (infolding) of hypodermis (epithelium) from the posterior surface of opisthosomal limb buds. Scorpion book lungs are formed near the bilateral sites of earlier limb buds. Hypodermal invaginations in the ventral opisthosoma result in spiracles and sac-like cavities (atria). In early histological sections of embryo book lungs, widening of the atrial entrance of some lamellae (air channels, air sacs, saccules) was interpreted as an indication of invagination as hypothesized for book gill lamellae. The hypodermal infolding was thought to produce the many rows of lamellar precursor cells anterior to the atrium. The ultrastructure of scorpion book lung development is compared herein with earlier investigations of book gill formation. Results In scorpion embryos, there is ingression (inward migration) of atrial hypodermal cells rather than invagination or infolding of the atrial hypodermal layer. The ingressing cells proliferate and align in rows anterior to the atrium. Their apical-basal polarity results in primordial air channels among double rows of cells. The cuticular walls of the air channels are produced by secretion from the apical surfaces of the aligned cells. Since the precursor cells are in rows, their secreted product is also in rows (i.e., primordial air channels, saccules). For each double row of cells, their opposed basal surfaces are gradually separated by a hemolymph channel of increasing width. Conclusions The results from this and earlier studies show there are differences and similarities in the formation of book lung and book gill lamellae. The homology hypothesis for these respiratory organs is thus supported or not supported depending on which developmental features are emphasized. For both organs, when the epithelial cells are in position, their apical-basal polarity results in alternate page-like channels of hemolymph and air or water with outward directed hemolymph saccules for book gills and inward directed air saccules for book lungs. PMID:21791110

Transcription Factor Erg Variants and Functional Diversification of Chondrocytes during Limb Long Bone Development

PubMed Central

Iwamoto, Masahiro; Higuchi, Yoshinobu; Koyama, Eiki; Enomoto-Iwamoto, Motomi; Kurisu, Kojiro; Yeh, Helena; Abrams, William R.; Rosenbloom, Joel; Pacifici, Maurizio

2000-01-01

During limb development, chondrocytes located at the epiphyseal tip of long bone models give rise to articular tissue, whereas the more numerous chondrocytes in the shaft undergo maturation, hypertrophy, and mineralization and are replaced by bone cells. It is not understood how chondrocytes follow these alternative pathways to distinct fates and functions. In this study we describe the cloning of C-1-1, a novel variant of the ets transcription factor ch-ERG. C-1-1 lacks a short 27–amino acid segment located ∼80 amino acids upstream of the ets DNA binding domain. We found that in chick embryo long bone anlagen, C-1-1 expression characterizes developing articular chondrocytes, whereas ch-ERG expression is particularly prominent in prehypertrophic chondrocytes in the growth plate. To analyze the function of C-1-1 and ch-ERG, viral vectors were used to constitutively express each factor in developing chick leg buds and cultured chondrocytes. We found that virally driven expression of C-1-1 maintained chondrocytes in a stable and immature phenotype, blocked their maturation into hypertrophic cells, and prevented the replacement of cartilage with bone. It also induced synthesis of tenascin-C, an extracellular matrix protein that is a unique product of developing articular chondrocytes. In contrast, virally driven expression of ch-ERG significantly stimulated chondrocyte maturation in culture, as indicated by increases in alkaline phosphatase activity and deposition of a mineralized matrix; however, it had modest effects in vivo. The data show that C-1-1 and ch-ERG have diverse biological properties and distinct expression patterns during skeletogenesis, and are part of molecular mechanisms by which limb chondrocytes follow alternative developmental pathways. C-1-1 is the first transcription factor identified to date that appears to be instrumental in the genesis and function of epiphyseal articular chondrocytes. PMID:10893254

Fine-tuning the onset of myogenesis by homeobox proteins that interact with the Myf5 limb enhancer

PubMed Central

Daubas, Philippe; Duval, Nathalie; Bajard, Lola; Langa Vives, Francina; Robert, Benoît; Mankoo, Baljinder S.; Buckingham, Margaret

2015-01-01

ABSTRACT Skeletal myogenesis in vertebrates is initiated at different sites of skeletal muscle formation during development, by activation of specific control elements of the myogenic regulatory genes. In the mouse embryo, Myf5 is the first myogenic determination gene to be expressed and its spatiotemporal regulation requires multiple enhancer sequences, extending over 120 kb upstream of the Mrf4-Myf5 locus. An enhancer, located at −57/−58 kb from Myf5, is responsible for its activation in myogenic cells derived from the hypaxial domain of the somite, that will form limb muscles. Pax3 and Six1/4 transcription factors are essential activators of this enhancer, acting on a 145-bp core element. Myogenic progenitor cells that will form the future muscle masses of the limbs express the factors necessary for Myf5 activation when they delaminate from the hypaxial dermomyotome and migrate into the forelimb bud, however they do not activate Myf5 and the myogenic programme until they have populated the prospective muscle masses. We show that Msx1 and Meox2 homeodomain-containing transcription factors bind in vitro and in vivo to specific sites in the 145-bp element, and are implicated in fine-tuning activation of Myf5 in the forelimb. Msx1, when bound between Pax and Six sites, prevents the binding of these key activators, thus inhibiting transcription of Myf5 and consequent premature myogenic differentiation. Meox2 is required for Myf5 activation at the onset of myogenesis via direct binding to other homeodomain sites in this sequence. Thus, these homeodomain factors, acting in addition to Pax3 and Six1/4, fine-tune the entry of progenitor cells into myogenesis at early stages of forelimb development. PMID:26538636

Apical dominance in saffron and the involvement of the branching enzymes CCD7 and CCD8 in the control of bud sprouting

PubMed Central

2014-01-01

Background In saffron (Crocus sativus), new corms develop at the base of every shoot developed from the maternal corm, a globular underground storage stem. Since the degree of bud sprouts influences the number and size of new corms, and strigolactones (SLs) suppress growth of pre-formed axillary bud, it was considered appropriate to investigate SL involvement in physiology and molecular biology in saffron. We focused on two of the genes within the SL pathway, CCD7 and CCD8, encoding carotenoid cleavage enzymes required for the production of SLs. Results The CsCCD7 and CsCCD8 genes are the first ones isolated and characterized from a non-grass monocotyledonous plant. CsCCD7 and CsCCD8 expression showed some overlapping, although they were not identical. CsCCD8 was highly expressed in quiescent axillary buds and decapitation dramatically reduced its expression levels, suggesting its involvement in the suppression of axillary bud outgrowth. Furthermore, in vitro experiments showed also the involvement of auxin, cytokinin and jasmonic acid on the sprouting of axillary buds from corms in which the apical bud was removed. In addition, CsCCD8 expression, but not CsCCD7, was higher in the newly developed vascular tissue of axillary buds compared to the vascular tissue of the apical bud. Conclusions We showed that production and transport of auxin in saffron corms could act synergistically with SLs to arrest the outgrowth of the axillary buds, similar to the control of above-ground shoot branching. In addition, jasmonic acid seems to play a prominent role in bud dormancy in saffron. While cytokinins from roots promote bud outgrowth. In addition the expression results of CsCCD8 suggest that SLs could positively regulate procambial activity and the development of new vascular tissues connecting leaves with the mother corm. PMID:24947472

Two human homeobox genes, c1 and c8: structure analysis and expression in embryonic development.

PubMed

Simeone, A; Mavilio, F; Acampora, D; Giampaolo, A; Faiella, A; Zappavigna, V; D'Esposito, M; Pannese, M; Russo, G; Boncinelli, E

1987-07-01

Two human cDNA clones (HHO.c1.95 and HHO.c8.5111) containing a homeobox region have been characterized, and the respective genomic regions have been partially analyzed. Expression of the corresponding genes, termed c1 and c8, was evaluated in different organs and body parts during human embryonic/fetal development. HHO.c1.95 apparently encodes a 217-amino acid protein containing a class I homeodomain that shares 60 out of 61 amino acid residues with the Antennapedia homeodomain of Drosophila melanogaster. HHO.c8.5111 encodes a 153-amino acid protein containing a homeodomain identical to that of the frog AC1 gene. Clones HHO.c1 and HHO.c8 detect by blot-hydridization one and two specific polyadenylylated transcripts, respectively. These are differentially expressed in spinal cord, backbone rudiments, limb buds (or limbs), heart, and skin of human embryos and early fetuses in the 5- to 9-week postfertilization period, thus suggesting that the c1 and c8 genes play a key role in a variety of developmental processes. Together, the results of the embryonic/fetal expression of c1 and c8 and those of two previously analyzed genes (c10 and c13) indicate a coherent pattern of expression of these genes in early human ontogeny.

Fetal and post-natal lung defects reveal a novel and required role for Fgf8 in lung development

PubMed Central

Yu, Shibin; Poe, Bryan; Schwarz, Margaret; Elliot, Sarah; Albertine, Kurt H.; Fenton, Stephen; Garg, Vidu; Moon, Anne M.

2016-01-01

The fibroblast growth factor, FGF8, has been shown to be essential for vertebrate cardiovascular, craniofacial, brain and limb development. Here we report that Fgf8 function is required for normal progression through the late fetal stages of lung development that culminate in alveolar formation. Budding, lobation and branching morphogenesis are unaffected in early stage Fgf8 hypomorphic and conditional mutant lungs. Excess proliferation during fetal development disrupts distal airspace formation, mesenchymal and vascular remodeling, and Type I epithelial cell differentiation resulting in postnatal respiratory failure and death. Our findings reveal a previously unknown, critical role for Fgf8 function in fetal lung development and suggest that this factor may also contribute to postnatal alveologenesis. Given the high number of premature infants with alveolar dysgenesis and lung dysplasia, and the accumulating evidence that short-term benefits of available therapies may be outweighed by long term detrimental effects on postnatal alveologenesis, the therapeutic implications of identifying a factor or pathway that can be targeted to stimulate normal alveolar development are profound. PMID:20727874

β-Catenin signaling regulates temporally discrete phases of anterior taste bud development

PubMed Central

Thirumangalathu, Shoba; Barlow, Linda A.

2015-01-01

The sense of taste is mediated by multicellular taste buds located within taste papillae on the tongue. In mice, individual taste buds reside in fungiform papillae, which develop at mid-gestation as epithelial placodes in the anterior tongue. Taste placodes comprise taste bud precursor cells, which express the secreted factor sonic hedgehog (Shh) and give rise to taste bud cells that differentiate around birth. We showed previously that epithelial activation of β-catenin is the primary inductive signal for taste placode formation, followed by taste papilla morphogenesis and taste bud differentiation, but the degree to which these later elements were direct or indirect consequences of β-catenin signaling was not explored. Here, we define discrete spatiotemporal functions of β-catenin in fungiform taste bud development. Specifically, we show that early epithelial activation of β-catenin, before taste placodes form, diverts lingual epithelial cells from a taste bud fate. By contrast, β-catenin activation a day later within Shh+ placodes, expands taste bud precursors directly, but enlarges papillae indirectly. Further, placodal activation of β-catenin drives precocious differentiation of Type I glial-like taste cells, but not other taste cell types. Later activation of β-catenin within Shh+ precursors during papilla morphogenesis also expands taste bud precursors and accelerates Type I cell differentiation, but papilla size is no longer enhanced. Finally, although Shh regulates taste placode patterning, we find that it is dispensable for the accelerated Type I cell differentiation induced by β-catenin. PMID:26525674

Gravi-photomorphogenesis of the moss Pottia intermedia protonemata

NASA Astrophysics Data System (ADS)

Demkiv, O. T.; Kyjak, N. Y.; Khorkavtsiv, Y. D.; Kit, N. A.

The protonemata development proceeds in the process of gradual differentiation of growing apical cells and intercalar cells the shortened lateral branches of the latters being transformed into three-dimensional gametophore buds (Demkiv et al., 1991). Normal course of plant development needs favourable external conditions. Sometimes, however, external environment agents can accelerate the development of organism. So, apical protonema cells of darkgrown gravitropic P. intermedia differentiate gametophore-buds in light of low intensity (Ripetskyj, 1999). We investigate the influence of gravistimulation on bud formation in haploid and diploid P. intermedia protonema. Diploid protonema was found to react on light weaker than haploid one. Under the influence of light the darkgrown apical cells and lateral branches of haploid protonema were directly transformed into buds, while in diploid protonema at first the formation of bundles of rhizoid type filaments takes place on the tips of caulonema and buds appeared in center of such bundles. The participation of gravity in gametophore bud formation was assessed by clinorotating protonema in darkness. Being illuminated such protonema also developed buds quickly the latters being formed along all stolon. It can be suggested that at 1g the growth zone of apical cells actively attract inductors of bud formation. During clinorotation the inductors probably are transferred much more slower than under stationary state and that is why the buds arised not only at the tips of stolons but along all their length. It is known that gametophore bud formation can be stimulated by exogenous phytohormones. As M. Bopp (1980) has shown, that kinetin selectively promotes bud formation on moss protonema. Our observations have shown 0,5 -- 50 μ M of kinetin stimulate the bud formation on diploid aposporic protonema much more effectively that on haploid one. It can be concluded that the amount of endogenous cytokinins in haploid protonemal cells is sufficiently high and the addition of exogenous kinetin may be superfluous for bud formation being, however, not superfluous in diploid. It was established earlier that IAA participates gametophore bud formation stimulating caulonema differentiation and inducing the competence to cytokinins action. 3,0 μ M and 30,0 μ M phytotropin of N-1-naphthylphthalamic acid (NPA), the blockator of IAA efflux, were used in our investigations. 1,0 μ M of synthesized auxin I-NAA did not essentially influence gametophore bud formation in both haploid and diploid P. intermedia protonema. However, during combine action of NPA and NAA the inhibitory effect of 3,0 μ M of NPA was eliminated the ability of gravitropic protonema to form gametophore buds being renewed.

Synchronisms and correlations of spring phenology between apical and lateral meristems in two boreal conifers.

PubMed

Antonucci, Serena; Rossi, Sergio; Deslauriers, Annie; Lombardi, Fabio; Marchetti, Marco; Tognetti, Roberto

2015-10-01

Phenological synchronisms between apical and lateral meristems could clarify some aspects related to the physiological relationships among the different organs of trees. This study correlated the phenological phases of bud development and xylem differentiation during spring 2010-14 in balsam fir (Abies balsamea Mill.) and black spruce [(Picea mariana Mill. (BSP)] of the Monts-Valin National Park (Quebec, Canada) by testing the hypothesis that bud development occurs after the reactivation of xylem growth. From May to September, we conducted weekly monitoring of xylem differentiation using microcores and bud development with direct observations on terminal branches. Synchronism between the beginning of bud development and xylem differentiation was found in both species with significant correlations between the phases of bud and xylem phenology. Degree-day sum was more appropriate in assessing the date of bud growth resumption, while thermal thresholds were more suitable for cambium phenology. Our results provide new knowledge on the dynamics of spring phenology and novel information on the synchronisms between two meristems in coniferous trees. The study demonstrates the importance of precisely defining the phases of bud development in order to correctly analyse the relationships with xylem phenology. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Phenology of perennial native grass below-ground axillary buds in the northern mixed-grass prairie

USDA-ARS?s Scientific Manuscript database

Vegetative reproduction from belowground bud banks is the primary driver of grassland systems. Despite the importance of vegetative reproduction, the timing of belowground bud recruitment is unknown for most dominant, perennial native grasses as is the relationship between bud development and envir...

Coevolutionary patterning of teeth and taste buds

PubMed Central

Bloomquist, Ryan F.; Parnell, Nicholas F.; Phillips, Kristine A.; Fowler, Teresa E.; Yu, Tian Y.; Sharpe, Paul T.; Streelman, J. Todd

2015-01-01

Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium. PMID:26483492

Coevolutionary patterning of teeth and taste buds.

PubMed

Bloomquist, Ryan F; Parnell, Nicholas F; Phillips, Kristine A; Fowler, Teresa E; Yu, Tian Y; Sharpe, Paul T; Streelman, J Todd

2015-11-03

Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium.

Polyp morphogenesis in a scyphozoan: Evidence for a head inhibitor from the presumptive foot end in vegetative buds ofCassiopeia andromeda.

PubMed

Neumann, R

1977-03-01

Buds ofCassiopeia andromeda have been transected into fragments of various sizes. Depending on their original position in the organism, on their size and on the age of the dissected buds, the fragments either regenerated or developed to a solitary polyp's head without stalk and peduncle. Generally, basal fragments tended to regenerate complete buds, young apical parts mostly differenciated polyp heads whereas apical and middle parts of progressively older buds regenerated buds with increasing frequency. To explain the alteration of the developmental capacities a head inhibitor is postulated which originates from the basal end of the buds and which expands towards the apical pole with increasing age of the buds.

Placental transfer and developmental effects of 9-cis retinoic acid in mice.

PubMed

Kochhar, D M; Jiang, H; Penner, J D; Heyman, R A

1995-04-01

9-cis retinoic acid (RA) is a naturally occurring isomer of all-trans RA. While both isomers can bind with high affinity and activate RA receptors, only 9-cis RA is the specific ligand for the retinoid X receptors. 9-cis RA has also been shown to be much more potent than all-trans RA in inducing digit duplication in the chick embryo wing bud. To gain further insight into its mechanisms, here we investigated the teratogenic activity in pregnant mice of 9-cis RA and compared it with those of all-trans RA and 13-cis RA. Using frequency and severity of limb reduction defects as well as palatal clefts in the resultant fetuses as indicators, we found that orally administered 9-cis RA was one-half as potent a teratogen as all-trans RA. That 9-cis RA was intrinsically less active than all-trans RA was deduced by comparing the inhibitory activities of the two retinoids in the limb bud mesenchymal cell micromass cultures using chondrogenesis as an end-point. Since placental transfer of cis isomers of RA is generally poor, we monitored the identities and amounts of retinoids in the embryo after administration of 9-cis RA to the mother. We found that 9-cis RA undergoes extensive metabolism and isomerization during absorption resulting in a number of metabolites in the maternal circulation within 30 min after administration. Although some of these metabolites remain to be identified, the most abundant RA isomers in the plasma coeluted with 13-cis RA.(ABSTRACT TRUNCATED AT 250 WORDS)

DEVELOPING A SENSE OF TASTE

PubMed Central

Kapsimali, Marika; Barlow, Linda A.

2012-01-01

Taste buds are found in a distributed array on the tongue surface, and are innervated by cranial nerves that convey taste information to the brain. For nearly a century, taste buds were thought to be induced by nerves late in embryonic development. However, this view has shifted dramatically. A host of studies now indicate that taste bud development is initiated and proceeds via processes that are nerve-independent, occur long before birth, and governed by cellular and molecular mechanisms intrinsic to the developing tongue. Here we review the state of our understanding of the molecular and cellular regulation of taste bud development, incorporating important new data obtained through the use of two powerful genetic systems, mouse and zebrafish. PMID:23182899

Bud development and shoot morphology in relation to crown location

PubMed Central

Kukk, Maarja; Sõber, Anu

2015-01-01

Plant architecture is shaped by endogenous growth processes interacting with the local environment. The current study investigated crown development in young black alder trees, assessing the effects of local light conditions and branch height on individual bud mass and contents. In addition, we examined the characteristics of parent shoots [the cross-sectional area (CSA) of stem and total leaf area, shoot length, the number of nodes, the number and total mass of buds per shoot] and leaf–stem as well as bud–stem allometry, as several recent studies link bud development to hydraulic architecture. We sampled shoots from top branches and two lower-crown locations: one subjected to deep shade and the other resembling the upper branches in light availability. Sampling was carried out three times between mid-July and late October, spanning from the early stages of bud growth to dormancy. Individual bud mass and shoot characteristics varied in response to light conditions, whereas leaf–stem allometry depended on branch height, most likely compensating for the increasing length of hydraulic pathways. Despite the differences in individual bud mass, the number of preformed leaves varied little across the crown, indicating that the plasticity in shoot characteristics was mainly achieved by neoformation. The relationship between total bud mass and stem CSA scaled similarly across crown locations. However, scaling slopes gradually decreased throughout the sampling period, driven by bud rather than by stem growth. This suggests that the allometry of total bud mass and CSA of stem is regulated locally, instead of resulting from crown-level processes. PMID:26187607

β-Catenin signaling regulates temporally discrete phases of anterior taste bud development.

PubMed

Thirumangalathu, Shoba; Barlow, Linda A

2015-12-15

The sense of taste is mediated by multicellular taste buds located within taste papillae on the tongue. In mice, individual taste buds reside in fungiform papillae, which develop at mid-gestation as epithelial placodes in the anterior tongue. Taste placodes comprise taste bud precursor cells, which express the secreted factor sonic hedgehog (Shh) and give rise to taste bud cells that differentiate around birth. We showed previously that epithelial activation of β-catenin is the primary inductive signal for taste placode formation, followed by taste papilla morphogenesis and taste bud differentiation, but the degree to which these later elements were direct or indirect consequences of β-catenin signaling was not explored. Here, we define discrete spatiotemporal functions of β-catenin in fungiform taste bud development. Specifically, we show that early epithelial activation of β-catenin, before taste placodes form, diverts lingual epithelial cells from a taste bud fate. By contrast, β-catenin activation a day later within Shh(+) placodes, expands taste bud precursors directly, but enlarges papillae indirectly. Further, placodal activation of β-catenin drives precocious differentiation of Type I glial-like taste cells, but not other taste cell types. Later activation of β-catenin within Shh(+) precursors during papilla morphogenesis also expands taste bud precursors and accelerates Type I cell differentiation, but papilla size is no longer enhanced. Finally, although Shh regulates taste placode patterning, we find that it is dispensable for the accelerated Type I cell differentiation induced by β-catenin. © 2015. Published by The Company of Biologists Ltd.

Inhibition of Shh signalling in the chick wing gives insights into digit patterning and evolution.

PubMed

Pickering, Joseph; Towers, Matthew

2016-10-01

In an influential model of pattern formation, a gradient of Sonic hedgehog (Shh) signalling in the chick wing bud specifies cells with three antero-posterior positional values, which give rise to three morphologically different digits by a self-organizing mechanism with Turing-like properties. However, as four of the five digits of the mouse limb are morphologically similar in terms of phalangeal pattern, it has been suggested that self-organization alone could be sufficient. Here, we show that inhibition of Shh signalling at a specific stage of chick wing development results in a pattern of four digits, three of which can have the same number of phalanges. These patterning changes are dependent on a posterior extension of the apical ectodermal ridge, and this also allows the additional digit to arise from the Shh-producing cells of the polarizing region - an ability lost in ancestral theropod dinosaurs. Our analyses reveal that, if the specification of antero-posterior positional values is curtailed, self-organization can then produce several digits with the same number of phalanges. We present a model that may give important insights into how the number of digits and phalanges has diverged during the evolution of avian and mammalian limbs. © 2016. Published by The Company of Biologists Ltd.

The glossopharyngeal nerve controls epithelial expression of Sprr2a and Krt13 around taste buds in the circumvallate papilla.

PubMed

Miura, Hirohito; Kusakabe, Yuko; Hashido, Kento; Hino, Akihiro; Ooki, Makoto; Harada, Shuitsu

2014-09-19

Tastants reach the tip of taste bud cells through taste pores which are openings in the epithelium. We found Sprr2a is selectively expressed in the upper layer of the epithelium surrounding taste buds in the circumvallate papilla (CV) where the epithelium is organized into taste pores. Sprr2a is a member of a small proline-rich protein family, which is suggested to be involved in the restitution/migration phase of epithelial wound healing. The expression of Sprr2a was restricted to the upper layer and largely segregated with Ptch1 expression that is restricted to the basal side of the epithelium around the taste buds. Denervation resulted in the gradual loss of Sprr2a-expressing cells over 10 days similarly to that of taste bud cells which is in contrast to the rapid loss of Ptch1 expression. We also found that denervation caused an increase of Keratin (Krt)13 expression around taste buds that corresponded with the disappearance of Sprr2a and Ptch1 expression. Taste buds were surrounded by Krt13-negative cells in the CV in control mice. However, at 6 days post-denervation, taste buds were tightly surrounded by Krt13-positive cells. During taste bud development, taste bud cells emerged together with Krt13-negtive cells, and Sprr2a expression was increased along with the progress of taste bud development. These results demonstrate that regional gene expression surrounding taste buds is associated with taste bud formation and controlled by the innervating taste nerve. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Differential expression of myogenic regulatory genes and Msx-1 during dedifferentiation and redifferentiation of regenerating amphibian limbs.

PubMed

Simon, H G; Nelson, C; Goff, D; Laufer, E; Morgan, B A; Tabin, C

1995-01-01

An amputated limb of an adult urodele amphibian is capable of undergoing regeneration. The new structures form from an undifferentiated mass of cells called the regenerative blastema. The cells of the blastema are believed to derive from differentiated tissues of the adult limb. However, the exact source of these cells and the process by which they undergo dedifferentiation are poorly understood. In order to elucidate the molecular and cellular basis for dedifferentiation we isolated a number of genes which are potential regulators of the process. These include Msx-1, which is believed to support the undifferentiated and proliferative state of cells in the embryonic limb bud; and two members of the myogenic regulatory gene family, MRF-4 and Myf-5, which are expressed in differentiated muscle and regulate muscle-specific gene activity. As anticipated, we find that Msx-1 is strongly up-regulated during the initiation of regeneration. It remains expressed throughout regeneration but is not found in the fully regenerated limb. The myogenic gene MRF-4 has the reverse expression pattern. It is expressed in adult limb muscle, is rapidly shut off in early regenerative blastemas, and is only reexpressed at the completion of regeneration. These kinetics are paralleled by those of a muscle-specific Myosin gene. In contrast Myf-5, a second member of the myogenic gene family, continues to be expressed throughout the regenerative process. Thus, MRF-4 and Myf-5 are likely to play distinct roles during regeneration. MRF-4 may directly regulate muscle phenotype and as such its repression may be a key event in dedifferentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Protection from ethanol-induced limb malformations by the superoxide dismutase/catalase mimetic, EUK-134.

PubMed

Chen, Shao-Yu; Dehart, Deborah B; Sulik, Kathleen K

2004-08-01

Based on previous in vitro studies that have illustrated prevention of ethanol-induced cell death by antioxidants, using an in vivo model, we have tested the anti-teratogenic potential of a potent synthetic superoxide dismutase plus catalase mimetic, EUK-134. The developing limb of C57BL/6J mice, which is sensitive to ethanol-induced reduction defects, served as the model system. On their ninth day of pregnancy, C57BL/6J mice were administered ethanol (two intraperitoneal doses of 2.9 g/kg given 4 h apart) alone or in combination with EUK-134 (two doses of 10 mg/kg). Pregnant control mice were similarly treated with either vehicle or EUK-134, alone. Within 15 h of the initial ethanol exposure, excessive apoptotic cell death was observed in the apical ectodermal ridge (AER) of the newly forming forelimb buds. Forelimb defects, including postaxial ectrodactyly, metacarpal, and ulnar deficiencies, occurred in 67.3% of the ethanol-exposed fetuses that were examined at 18 days of gestation. The right forelimbs were preferentially affected. No limb malformations were observed in control fetuses. Cell death in the AER of embryos concurrently exposed to ethanol and EUK-134 was notably reduced compared with that in embryos from ethanol-treated dams. Additionally, the antioxidant treatment reduced the incidence of forelimb malformations to 35.9%. This work illustrates that antioxidants can significantly improve the adverse developmental outcome that results from ethanol exposure in utero, diminishing the incidence and severity of major malformations that result from exposure to this important human teratogen.

Gravity-induced buds formation from protonemata apical cells in the mosses

NASA Astrophysics Data System (ADS)

Kyyak, Natalia; Khorkavtsiv, Yaroslava

The acceleration of moss protonemata development after the exit it to light from darkness is important gravidependent morphogenetic manifestation of the moss protonemata. The accelerated development of mosses shows in transformation of apical protonemata cells into the gametophores buds (Ripetskyj et al., 1999). In order to establish, that such reaction on gravitation is general property of gravisensity species, or its typical only for single moss species, experiments with the following moss species - Bryum intermedium (Ludw.) Brig., Bryum caespiticium Hedw., Bryum argenteum Hedw., Dicranodontium denudatum (Brid.) Britt. were carried out. All these species in response to influence of gravitation were capable to form rich bunches of gravitropical protonemata in darkness, that testified to their gravisensity. After the transference of Petri dishes with gravitropical protonemata from darkness on light was revealed, that in 3 of the investigated species the gametophores buds were absent. Only B. argenteum has reacted to action of gravitation by buds formation from apical cells of the gravitropical protonemata. With the purpose of strengthening of buds formation process, the experiments with action of exogenous kinetin (in concentration of 10 (-6) M) were carried out. Kinetin essentially stimulated apical buds formation of B. argenteum. The quantity of apical buds has increased almost in three times in comparison with the control. Besides, on separate stolons a few (3-4) buds from one apical cell were formed. Experimentally was established, that the gametophores buds formation in mosses is controlled by phytohormones (Bopp, 1985; Demkiv et al., 1991). In conditions of gravity influence its essentially accelerated. Probably, gravity essentially strengthened acropetal transport of phytohormones and formation of attractive center in the protonemata apical cell. Our investigations have allowed to make the conclusion, that gravi-dependent formation of the apical buds is particular species-specific feature. Obviously, the important role in this process also played the duration of the period of gametophyte development. All species selected for this analysis, excepted B. argenteum, characterized by sufficiently long process of gametophyte development. On light the process of cells differentiation of these species and the buds formation occurs during 5-6 weeks, in B. argenteum - 16-18 days. The essential strengthening of process of buds formation on the apical cells was received under influence of exogenous kinetin that confirms the concept of key role of kinetin in gametophores buds formation.

Characterization of stem/progenitor cell cycle using murine circumvallate papilla taste bud organoid.

PubMed

Aihara, Eitaro; Mahe, Maxime M; Schumacher, Michael A; Matthis, Andrea L; Feng, Rui; Ren, Wenwen; Noah, Taeko K; Matsu-ura, Toru; Moore, Sean R; Hong, Christian I; Zavros, Yana; Herness, Scott; Shroyer, Noah F; Iwatsuki, Ken; Jiang, Peihua; Helmrath, Michael A; Montrose, Marshall H

2015-11-24

Leucine-rich repeat-containing G-protein coupled receptor 5-expressing (Lgr5(+)) cells have been identified as stem/progenitor cells in the circumvallate papillae, and single cultured Lgr5(+) cells give rise to taste cells. Here we use circumvallate papilla tissue to establish a three-dimensional culture system (taste bud organoids) that develops phenotypic characteristics similar to native tissue, including a multilayered epithelium containing stem/progenitor in the outer layers and taste cells in the inner layers. Furthermore, characterization of the cell cycle of the taste bud progenitor niche reveals striking dynamics of taste bud development and regeneration. Using this taste bud organoid culture system and FUCCI2 transgenic mice, we identify the stem/progenitor cells have at least 5 distinct cell cycle populations by tracking within 24-hour synchronized oscillations of proliferation. Additionally, we demonstrate that stem/progenitor cells have motility to form taste bud organoids. Taste bud organoids provides a system for elucidating mechanisms of taste signaling, disease modeling, and taste tissue regeneration.

Characterization of stem/progenitor cell cycle using murine circumvallate papilla taste bud organoid

PubMed Central

Aihara, Eitaro; Mahe, Maxime M.; Schumacher, Michael A.; Matthis, Andrea L.; Feng, Rui; Ren, Wenwen; Noah, Taeko K.; Matsu-ura, Toru; Moore, Sean R.; Hong, Christian I.; Zavros, Yana; Herness, Scott; Shroyer, Noah F.; Iwatsuki, Ken; Jiang, Peihua; Helmrath, Michael A.; Montrose, Marshall H.

2015-01-01

Leucine-rich repeat-containing G-protein coupled receptor 5-expressing (Lgr5+) cells have been identified as stem/progenitor cells in the circumvallate papillae, and single cultured Lgr5+ cells give rise to taste cells. Here we use circumvallate papilla tissue to establish a three-dimensional culture system (taste bud organoids) that develops phenotypic characteristics similar to native tissue, including a multilayered epithelium containing stem/progenitor in the outer layers and taste cells in the inner layers. Furthermore, characterization of the cell cycle of the taste bud progenitor niche reveals striking dynamics of taste bud development and regeneration. Using this taste bud organoid culture system and FUCCI2 transgenic mice, we identify the stem/progenitor cells have at least 5 distinct cell cycle populations by tracking within 24-hour synchronized oscillations of proliferation. Additionally, we demonstrate that stem/progenitor cells have motility to form taste bud organoids. Taste bud organoids provides a system for elucidating mechanisms of taste signaling, disease modeling, and taste tissue regeneration. PMID:26597788

Early dietary sodium restriction disrupts the peripheral anatomical development of the gustatory system.

PubMed

Krimm, R F; Hill, D L

1999-05-01

Dietary sodium restriction has profound effects on the development of peripheral taste function and central taste system anatomy. This study examined whether early dietary sodium restriction also affects innervation of taste buds. The number of geniculate ganglion cells that innervate single fungiform taste buds were quantified for the midregion of the tongue in two groups of rats: those fed either a low-sodium diet and those fed a sodium replete diet (control rats) from early prenatal development through adulthood. The same mean number of ganglion cells in developmentally sodium-restricted and control adult rats innervated taste buds on the midregion of the tongue. However, the characteristic relationship of the larger the taste bud, the more neurons that innervate it did not develop in sodium-restricted rats. The failure to form such a relationship in experimental rats was likely due to a substantially smaller mean taste bud volume than controls and probably not to changes in innervation. Further experiments demonstrated that the altered association between number of innervating neurons and taste bud size in restricted rats was reversible. Feeding developmentally sodium-restricted rats a sodium replete diet at adulthood resulted in an increase in taste bud size. Accordingly, the high correlation between taste bud volume and innervation was established in sodium-replete rats. Findings from the current study reveal that early dietary manipulations influence neuron-target interactions; however, the effects of dietary sodium restriction on peripheral gustatory anatomy can be completely restored, even in adult animals.

Temperature regulation of bud-burst phenology within and among years in a young Douglas-fir (Pseudotsuga menziesii) plantation in western Washington, USA.

PubMed

Bailey, John D; Harrington, Constance A

2006-04-01

Past research has established that terminal buds of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings from many seed sources have a chilling requirement of about 1200 h at 0-5 degrees C; once chilled, temperatures > 5 degrees C force bud burst via accumulation of heat units. We tested this sequential bud-burst model in the field to determine whether terminal buds of trees in cooler microsites, which receive less heat forcing, develop more slowly than those in warmer microsites. For three years we monitored terminal bud development in young saplings as well as soil and air temperatures on large, replicated plots in a harvest unit; plots differed in microclimate based on amount of harvest residue and shade from neighboring stands. In two of three years, trees on cooler microsites broke bud 2 to 4 days earlier than those on warmer microsites, despite receiving less heat forcing from March to May each year. A simple sequential model did not predict cooler sites having earlier bud burst nor did it correctly predict the order of bud burst across the three years. We modified the basic heat-forcing model to initialize, or reset to zero, the accumulation of heat units whenever significant freezing temperature events (> or = 3 degree-hours day(-1) < 0 degrees C) occurred; this modified model correctly predicted the sequence of bud burst across years. Soil temperature alone or in combination with air temperature did not improve our predictions of bud burst. Past models of bud burst have relied heavily on data from controlled experiments with simple temperature patterns; analysis of more variable temperature patterns from our 3-year field trial, however, indicated that simple models of bud burst are inaccurate. More complex models that incorporate chilling hours, heat forcing, photoperiod and the occurrence of freeze events in the spring may be needed to predict effects of future silvicultural treatments as well to interpret the implications of climate-change scenarios. Developing and testing new models will require data from both field and controlled-environment experiments.

Embryonic development of pleuropodia of the cicada, Magicicada cassini

PubMed Central

Strauß, Johannes; Lakes-Harlan, Reinhard

2006-01-01

In many insects the first abdominal segment possesses embryonic appendages called pleuropodia. Here we show the embryogenesis of pleuropodial cells of the periodical cicada, Magicicada cassini (Fisher 1851) (Insecta, Homoptera, Cicadidae). An antibody, anti-horseradish perioxidase (HRP), that is usually neuron-specific strongly marked the pleuropodial anlagen and revealed their ectodermal origin shortly after limb bud formation. Thereafter the cells sank into the epidermis and their apical parts enlarged. A globular part protruded from the body wall. Filamentous structures were marked at the stem region and into the apical dilation. In later embryonic stages the pleuropodia degenerated. Despite the binding of anti-HRP the cells had no morphological neuronal characters and cannot be regarded as neurons. The binding indicates that glycosylated cell surface molecules contribute to the adhesion between the presumably glandular pleuropodial cells. In comparison, anti-HRP does not mark the pleuropodia of Orthoptera. PMID:19537987

Estrogen signaling is not required for prostatic bud patterning or for its disruption by 2,3,7,8-tetrachlorodibenzo-p-dioxin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allgeier, Sarah Hicks; Vezina, Chad M.; Lin, T.-M.

2009-08-15

Estrogens play an important role in prostatic development, health, and disease. While estrogen signaling is essential for normal postnatal prostate development, little is known about its prenatal role in control animals. We tested the hypothesis that estrogen signaling is needed for normal male prostatic bud patterning. Budding patterns were examined by scanning electron microscopy of urogenital sinus epithelium from wild-type mice, mice lacking estrogen receptor (ER){alpha}, ER{beta}, or both, and wild-type mice exposed to the antiestrogen ICI 182,780. Budding phenotypes did not detectably differ among any of these groups, strongly suggesting that estrogen signaling is not needed to establish themore » prototypical prostatic budding pattern seen in control males. This finding contributes to our understanding of the effects of low-level estrogen exposure on early prostate development. In utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can greatly alter the pattern in which prostatic buds form and reduce their number. For several reasons, including a prior observation that inhibitory effects of TCDD on prostatic budding in rats depend heavily on the sex of adjacent fetuses, we tested the hypothesis that estrogen signaling is needed for TCDD to disrupt prostatic budding. However, budding did not detectably differ among wild-type mice, or mice lacking ER{alpha}, ER{beta}, or both, that were exposed prenatally to TCDD (5 {mu}g/kg on embryonic day 13.5). Nor did ICI 182,780 detectably affect the response to TCDD. These results strongly suggest that estrogen signaling is not needed for TCDD to inhibit prostatic epithelial budding.« less

Control of head morphogenesis in an invertebrate asexually produced larva-like bud ( Cassiopea andromeda; Cnidaria: Scyphozoa).

PubMed

Thieme, Claudia; Hofmann, Dietrich Kurt

2003-04-01

Scyphopolyps of Cassiopea andromeda propagate asexually by forming larva-like buds which separate from the parent in a developmentally quiescent state. These buds metamorphose into sessile polyps when exposed to specific biogenic, chemical inducers. Morphogenesis of transversely dissected buds indicates the presence of pattern-determining signals; whereas the basal bud fragments may still form a complete scyphistoma the apical bud fragments develop spontaneously in the absence of an inducer into a polyp head without stalk and foot. Based on these findings Neumann (dissertation, Cologne University, 1980) postulated a head-inhibiting signal which is released at the basal pole and inhibits head formation at the apical end. Contrary to this hypothesis dissection itself might induce the development of head structures. The present study deals with the control of polyp head formation in C. andromeda. It concentrates on two points, namely the postulated head inhibitor and the involvement of compounds known to act during metamorphosis (the enzyme protein kinase C and the specific metamorphosis inducer Z-GPGGPA). We found that compared to intact buds and apical bud fragments transversely incised buds reached an intermediate stage of head development. This confirms Neumann's hypothesis. Consequently we focused on the mode of action and the chemical nature of the head-inhibiting signal in C. andromeda. Our results indicate that the head inhibitor may be included in one of six pooled fractions isolated from bud homogenate via gel filtration on a Sephadex G-50 column. The inhibitor is supposed to be water-soluble and to have a molecular weight of 850-1,500 Da. Furthermore we prove that head formation is not promoted by the metamorphosis-inducer Z-GPGGPA but is prevented by the inhibitors psychosine, chelerythrine and RO-32-0432 showing the involvement of protein kinase C in this process.

Development of the spinal cord and peripheral nervous system in platypus (Ornithorhynchus anatinus) and short-beaked echidna (Tachyglossus aculeatus).

PubMed

Ashwell, Ken W S

2012-01-01

The modern monotremes (platypus and echidnas) are characterized by development of their young in a leathery egg that is laid into a nest or abdominal pouch. At hatching, the young are externally immature, with forelimbs capable of digitopalmar prehension, but hindlimbs little advanced beyond limb buds. The embryological collections at the Museum für Naturkunde in Berlin were used to examine the development of the spinal cord and early peripheral nervous system in developing monotremes and to correlate this with known behavioural development. Ventral root outgrowth to the bases of both the fore- and hindlimbs occurs at 6.0 mm crown-rump length (CRL), but invasion of both limbs does not happen until about 8.0-8.5 mm CRL. Differentiation of the ventral horn precedes the dorsal horn during incubation and separate medial and lateral motor columns can be distinguished before hatching. Rexed's laminae begin to appear in the dorsal horn in the first week after hatching, and gracile and cuneate fasciculi emerge during the first two post-hatching months. Qualitative and quantitative comparisons of the structure of the cervicothoracic junction spinal cord in the two monotremes with that in a diprotodont marsupial (the brush-tailed possum, Trichosurus vulpecula) of similar size at birth, did not reveal any significant structural differences between the monotremes and the marsupial. The precocious development of motor systems in the monotreme spinal cord is consistent with the behavioural requirements of the peri-hatching period, that is, rupture of embryonic membranes and egg, and digitopalmar prehension to grasp maternal hair or nest material.

Lgr5 Identifies Progenitor Cells Capable of Taste Bud Regeneration after Injury.

PubMed

Takeda, Norifumi; Jain, Rajan; Li, Deqiang; Li, Li; Lu, Min Min; Epstein, Jonathan A

2013-01-01

Taste buds are composed of a variety of taste receptor cell types that develop from tongue epithelium and are regularly replenished under normal homeostatic conditions as well as after injury. The characteristics of cells that give rise to regenerating taste buds are poorly understood. Recent studies have suggested that Lgr5 (leucine-rich repeat-containing G-protein coupled receptor 5) identifies taste bud stem cells that contribute to homeostatic regeneration in adult circumvallate and foliate taste papillae, which are located in the posterior region of the tongue. Taste papillae in the adult anterior region of the tongue do not express Lgr5. Here, we confirm and extend these studies by demonstrating that Lgr5 cells give rise to both anterior and posterior taste buds during development, and are capable of regenerating posterior taste buds after injury induced by glossopharyngeal nerve transection.

How and why does the areole meristem move in Echinocereus (Cactaceae)?

PubMed Central

Sánchez, Daniel; Grego-Valencia, Dalia; Terrazas, Teresa; Arias, Salvador

2015-01-01

Background and Aims In Cactaceae, the areole is the organ that forms the leaves, spines and buds. Apparently, the genus Echinocereus develops enclosed buds that break through the epidermis of the stem adjacent to the areole; this trait most likely represents a synapomorphy of Echinocereus. The development of the areole is investigated here in order to understand the anatomical modifications that lead to internal bud development and to supplement anatomical knowledge of plants that do not behave according to classical shoot theory. Methods The external morphology of the areole was documented and the anatomy was studied using tissue clearing, scanning electron microscopy and light microscopy for 50 species that represent the recognized clades and sections of the traditional classification of the genus, including Morangaya pensilis (Echinocereus pensilis). Key Results In Echinocereus, the areole is sealed by the periderm, and the areole meristem is moved and enclosed by the differential growth of the epidermis and surrounding cortex. The enclosed areole meristem is differentiated in a vegetative or floral bud, which develops internally and breaks through the epidermis of the stem. In Morangaya pensilis, the areole is not sealed by the periderm and the areole meristem is not enclosed. Conclusions The enclosed areole meristem and internal bud development are understood to be an adaptation to protect the meristem and the bud from low temperatures. The anatomical evidence supports the hypothesis that the enclosed bud represents one synapomorphy for Echinocereus and also supports the exclusion of Morangaya from Echinocereus. PMID:25399023

Longleaf pine bud development: influence of seedling nutrition

Treesearch

J. P. Barnett; D. P. Jackson; R. K. Dumroese

2010-01-01

A subset of seedlings from a larger study (Jackson and others 2006, 2007) were selected and evaluated for two growing seasons to relate bud development, and root-collar diameter (RCD), and height growth with three nursery fertilization rates. We chose seedlings in the 0.5 (lowest), 2.0 (mid-range), and 4.0 (highest) mg of nitrogen per seedling treatments. Buds moved...

Diversity in cell motility reveals the dynamic nature of the formation of zebrafish taste sensory organs.

PubMed

Soulika, Marina; Kaushik, Anna-Lila; Mathieu, Benjamin; Lourenço, Raquel; Komisarczuk, Anna Z; Romano, Sebastian Alejo; Jouary, Adrien; Lardennois, Alicia; Tissot, Nicolas; Okada, Shinji; Abe, Keiko; Becker, Thomas S; Kapsimali, Marika

2016-06-01

Taste buds are sensory organs in jawed vertebrates, composed of distinct cell types that detect and transduce specific taste qualities. Taste bud cells differentiate from oropharyngeal epithelial progenitors, which are localized mainly in proximity to the forming organs. Despite recent progress in elucidating the molecular interactions required for taste bud cell development and function, the cell behavior underlying the organ assembly is poorly defined. Here, we used time-lapse imaging to observe the formation of taste buds in live zebrafish larvae. We found that tg(fgf8a.dr17)-expressing cells form taste buds and get rearranged within the forming organs. In addition, differentiating cells move from the epithelium to the forming organs and can be displaced between developing organs. During organ formation, tg(fgf8a.dr17) and type II taste bud cells are displaced in random, directed or confined mode relative to the taste bud they join or by which they are maintained. Finally, ascl1a activity in the 5-HT/type III cell is required to direct and maintain tg(fgf8a.dr17)-expressing cells into the taste bud. We propose that diversity in displacement modes of differentiating cells acts as a key mechanism for the highly dynamic process of taste bud assembly. © 2016. Published by The Company of Biologists Ltd.

Response of cranberry weevil (Coleoptera: Curculionidae) to host plant volatiles.

PubMed

Szendrei, Zsofia; Malo, Edi; Stelinski, Lukasz; Rodriguez-Saona, Cesar

2009-06-01

The oligophagous cranberry weevil, Anthonomus musculus Say, causes economic losses to blueberry growers in New Jersey because females deposit eggs into developing flower buds and subsequent larval feeding damages buds, which fail to produce fruit. A cost-effective and reliable method is needed for monitoring this pest to correctly time insecticide applications. We studied the behavioral and antennal responses of adult A. musculus to its host plant volatiles to determine their potential for monitoring this pest. We evaluated A. musculus response to intact and damaged host plant parts, such as buds and flowers in Y-tube bioassays. We also collected and identified host plant volatiles from blueberry buds and open flowers and performed electroantennograms with identified compounds to determine the specific chemicals eliciting antennal responses. Male weevils were more attracted to blueberry flower buds and were repelled by conspecific-damaged buds compared with clean air. In contrast, females were more attracted to open flowers compared with flower buds. Nineteen volatiles were identified from blueberry buds; 10 of these were also emitted from blueberry flowers. Four of the volatiles emitted from both blueberry buds and flowers [hexanol, (Z)-3-hexenyl acetate, hexyl acetate, and (Z)-3-hexenyl butyrate] elicited strong antennal responses from A. musculus. Future laboratory and field testing of the identified compounds in combination with various trap designs is planned to develop a reliable monitoring trap for A. musculus.

Retinoic acid-independent expression of Meis2 during autopod patterning in the developing bat and mouse limb.

PubMed

Mason, Mandy K; Hockman, Dorit; Curry, Lyle; Cunningham, Thomas J; Duester, Gregg; Logan, Malcolm; Jacobs, David S; Illing, Nicola

2015-01-01

The bat has strikingly divergent forelimbs (long digits supporting wing membranes) and hindlimbs (short, typically free digits) due to the distinct requirements of both aerial and terrestrial locomotion. During embryonic development, the morphology of the bat forelimb deviates dramatically from the mouse and chick, offering an alternative paradigm for identifying genes that play an important role in limb patterning. Using transcriptome analysis of developing Natal long-fingered bat (Miniopterus natalensis) fore- and hindlimbs, we demonstrate that the transcription factor Meis2 has a significantly higher expression in bat forelimb autopods compared to hindlimbs. Validation by reverse transcriptase and quantitative polymerase chain reaction (RT-qPCR) and whole mount in situ hybridisation shows that Meis2, conventionally known as a marker of the early proximal limb bud, is upregulated in the bat forelimb autopod from CS16. Meis2 expression is localised to the expanding interdigital webbing and the membranes linking the wing to the hindlimb and tail. In mice, Meis2 is also expressed in the interdigital region prior to tissue regression. This interdigital Meis2 expression is not activated by retinoic acid (RA) signalling as it is present in the retained interdigital tissue of Rdh10 (trex/trex) mice, which lack RA. Additionally, genes encoding RA-synthesising enzymes, Rdh10 and Aldh1a2, and the RA nuclear receptor Rarβ are robustly expressed in bat fore- and hindlimb interdigital tissues indicating that the mechanism that retains interdigital tissue in bats also occurs independently of RA signalling. Mammalian interdigital Meis2 expression, and upregulation in the interdigital webbing of bat wings, suggests an important role for Meis2 in autopod development. Interdigital Meis2 expression is RA-independent, and retention of interdigital webbing in bat wings is not due to the suppression of RA-induced cell death. Rather, RA signalling may play a role in the thinning (rather than complete loss) of the interdigital tissue in the bat forelimb, while Meis2 may interact with other factors during both bat and mouse autopod development to maintain a pool of interdigital cells that contribute to digit patterning and growth.

Labeling and analysis of chicken taste buds using molecular markers in oral epithelial sheets

PubMed Central

Rajapaksha, Prasangi; Wang, Zhonghou; Venkatesan, Nandakumar; Tehrani, Kayvan F.; Payne, Jason; Swetenburg, Raymond L.; Kawabata, Fuminori; Tabata, Shoji; Mortensen, Luke J.; Stice, Steven L.; Beckstead, Robert; Liu, Hong-Xiang

2016-01-01

In chickens, the sensory organs for taste are the taste buds in the oral cavity, of which there are ~240–360 in total number as estimated by scanning electron microscopy (SEM). There is not an easy way to visualize all taste buds in chickens. Here, we report a highly efficient method for labeling chicken taste buds in oral epithelial sheets using the molecular markers Vimentin and α-Gustducin. Immediate tissue fixation following incubation with sub-epithelially injected proteases enabled us to peel off whole epithelial sheets, leaving the shape and integrity of the tissue intact. In the peeled epithelial sheets, taste buds labeled with antibodies against Vimentin and α-Gustducin were easily identified and counted under a light microscope and many more taste buds, patterned in rosette-like clusters, were found than previously reported with SEM. Broiler-type, female-line males have more taste buds than other groups and continue to increase the number of taste buds over stages after hatch. In addition to ovoid-shaped taste buds, big tube-shaped taste buds were observed in the chicken using 2-photon microscopy. Our protocol for labeling taste buds with molecular markers will factilitate future mechanistic studies on the development of chicken taste buds in association with their feeding behaviors. PMID:27853250

Labeling and analysis of chicken taste buds using molecular markers in oral epithelial sheets.

PubMed

Rajapaksha, Prasangi; Wang, Zhonghou; Venkatesan, Nandakumar; Tehrani, Kayvan F; Payne, Jason; Swetenburg, Raymond L; Kawabata, Fuminori; Tabata, Shoji; Mortensen, Luke J; Stice, Steven L; Beckstead, Robert; Liu, Hong-Xiang

2016-11-17

In chickens, the sensory organs for taste are the taste buds in the oral cavity, of which there are ~240-360 in total number as estimated by scanning electron microscopy (SEM). There is not an easy way to visualize all taste buds in chickens. Here, we report a highly efficient method for labeling chicken taste buds in oral epithelial sheets using the molecular markers Vimentin and α-Gustducin. Immediate tissue fixation following incubation with sub-epithelially injected proteases enabled us to peel off whole epithelial sheets, leaving the shape and integrity of the tissue intact. In the peeled epithelial sheets, taste buds labeled with antibodies against Vimentin and α-Gustducin were easily identified and counted under a light microscope and many more taste buds, patterned in rosette-like clusters, were found than previously reported with SEM. Broiler-type, female-line males have more taste buds than other groups and continue to increase the number of taste buds over stages after hatch. In addition to ovoid-shaped taste buds, big tube-shaped taste buds were observed in the chicken using 2-photon microscopy. Our protocol for labeling taste buds with molecular markers will factilitate future mechanistic studies on the development of chicken taste buds in association with their feeding behaviors.

The structure and dynamics of Nano Particles encapsulated by the SDS monolayer collapse at the water/TCE interface

PubMed Central

Shi, Wenxiong

2016-01-01

The super-saturated surfactant monolayer collapses with the nanoparticles (NPs) at the water/trichloroethylene (TCE) interface are investigated using molecular dynamics (MD) simulations. The results show that sodium alkyl sulfate (SDS) monolayer collapse is initiated by buckling and followed primarily by budding and the bud encapsulating the NPs and oil molecules. The developed bud detaches from the monolayer into a water phase and forms the swollen micelle emulsion with NPs and oil molecules. We investigate the wavelength of the initial budding and the theoretical description of the budding process. The wavelength of the monolayer increases with bending modulus. The energy barrier of the budding can be easily overcome by thermal fluctuation energy, which indicates that budding process proceeds rapidly. PMID:27853312

The structure and dynamics of Nano Particles encapsulated by the SDS monolayer collapse at the water/TCE interface

NASA Astrophysics Data System (ADS)

Shi, Wenxiong

2016-11-01

The super-saturated surfactant monolayer collapses with the nanoparticles (NPs) at the water/trichloroethylene (TCE) interface are investigated using molecular dynamics (MD) simulations. The results show that sodium alkyl sulfate (SDS) monolayer collapse is initiated by buckling and followed primarily by budding and the bud encapsulating the NPs and oil molecules. The developed bud detaches from the monolayer into a water phase and forms the swollen micelle emulsion with NPs and oil molecules. We investigate the wavelength of the initial budding and the theoretical description of the budding process. The wavelength of the monolayer increases with bending modulus. The energy barrier of the budding can be easily overcome by thermal fluctuation energy, which indicates that budding process proceeds rapidly.

Evidence for an expansion-based temporal Shh gradient in specifying vertebrate digit identities.

PubMed

Harfe, Brian D; Scherz, Paul J; Nissim, Sahar; Tian, Hua; McMahon, Andrew P; Tabin, Clifford J

2004-08-20

The zone of polarizing activity (ZPA) in the posterior limb bud produces Sonic Hedgehog (Shh) protein, which plays a critical role in establishing distinct fates along the anterior-posterior axis. This activity has been modeled as a concentration-dependent response to a diffusible morphogen. Using recombinase base mapping in the mouse, we determine the ultimate fate of the Shh-producing cells. Strikingly, the descendants of the Shh-producing cells encompass all cells in the two most posterior digits and also contribute to the middle digit. Our analysis suggests that, while specification of the anterior digits depends upon differential concentrations of Shh, the length of time of exposure to Shh is critical in the specification of the differences between the most posterior digits. Genetic studies of the effects of limiting accessibility of Shh within the limb support this model, in which the effect of the Shh morphogen is dictated by a temporal as well as a spatial gradient.

Climatic control of bud burst in young seedlings of nine provenances of Norway spruce.

PubMed

Søgaard, Gunnhild; Johnsen, Oystein; Nilsen, Jarle; Junttila, Olavi

2008-02-01

Detailed knowledge of temperature effects on the timing of dormancy development and bud burst will help evaluate the impacts of climate change on forest trees. We tested the effects of temperature applied during short-day treatment, duration of short-day treatment, duration of chilling and light regime applied during forcing on the timing of bud burst in 1- and 2-year-old seedlings of nine provenances of Norway spruce (Picea abies (L.) Karst.). High temperature during dormancy induction, little or no chilling and low temperature during forcing all delayed dormancy release but did not prevent bud burst or growth onset provided the seedlings were forced under long-day conditions. Without chilling, bud burst occurred in about 20% of seedlings kept in short days at 12 degrees C, indicating that young Norway spruce seedlings do not exhibit true bud dormancy. Chilling hastened bud burst and removed the long photoperiod requirement, but the effect of high temperature applied during dormancy induction was observed even after prolonged chilling. Extension of the short-day treatment from 4 to 8 or 12 weeks hastened bud burst. The effect of treatments applied during dormancy development was larger than that of provenance; in some cases no provenance effect was detected, but in 1-year-old seedlings, time to bud burst decreased linearly with increasing latitude of origin. Differences among provenances were complicated by different responses of some origins to light conditions under long-day forcing. In conclusion, timing of bud burst in Norway spruce seedlings is significantly affected by temperature during bud set, and these effects are modified by chilling and environmental conditions during forcing.

Transcriptome Profiling of Tiller Buds Provides New Insights into PhyB Regulation of Tillering and Indeterminate Growth in Sorghum1

PubMed Central

2016-01-01

Phytochrome B (phyB) enables plants to modify shoot branching or tillering in response to varying light intensities and ratios of red and far-red light caused by shading and neighbor proximity. Tillering is inhibited in sorghum genotypes that lack phytochrome B (58M, phyB-1) until after floral initiation. The growth of tiller buds in the first leaf axil of wild-type (100M, PHYB) and phyB-1 sorghum genotypes is similar until 6 d after planting when buds of phyB-1 arrest growth, while wild-type buds continue growing and develop into tillers. Transcriptome analysis at this early stage of bud development identified numerous genes that were up to 50-fold differentially expressed in wild-type/phyB-1 buds. Up-regulation of terminal flower1, GA2oxidase, and TPPI could protect axillary meristems in phyB-1 from precocious floral induction and decrease bud sensitivity to sugar signals. After bud growth arrest in phyB-1, expression of dormancy-associated genes such as DRM1, GT1, AF1, and CKX1 increased and ENOD93, ACCoxidase, ARR3/6/9, CGA1, and SHY2 decreased. Continued bud outgrowth in wild-type was correlated with increased expression of genes encoding a SWEET transporter and cell wall invertases. The SWEET transporter may facilitate Suc unloading from the phloem to the apoplast where cell wall invertases generate monosaccharides for uptake and utilization to sustain bud outgrowth. Elevated expression of these genes was correlated with higher levels of cytokinin/sugar signaling in growing buds of wild-type plants. PMID:26893475

Spatial Variability of Grapevine Bud Burst Percentage and Its Association with Soil Properties at Field Scale

PubMed Central

Li, Tao; Hao, Xinmei; Kang, Shaozhong

2016-01-01

There is a growing interest in precision viticulture with the development of global positioning system and geographical information system technologies. Limited information is available on spatial variation of bud behavior and its possible association with soil properties. The objective of this study was to investigate spatial variability of bud burst percentage and its association with soil properties based on 2-year experiments at a vineyard of arid northwest China. Geostatistical approach was used to describe the spatial variation in bud burst percentage within the vineyard. Partial least square regressions (PLSRs) of bud burst percentage with soil properties were used to evaluate the contribution of soil properties to overall spatial variability in bud burst percentage for the high, medium and low bud burst percentage groups. Within the vineyard, the coefficient of variation (CV) of bud burst percentage was 20% and 15% for 2012 and 2013 respectively. Bud burst percentage within the vineyard showed moderate spatial variability, and the overall spatial pattern of bud burst percentage was similar between the two years. Soil properties alone explained 31% and 37% of the total spatial variation respectively for the low group of 2012 and 2013, and 16% and 24% for the high group of 2012 and 2013 respectively. For the low group, the fraction of variations explained by soil properties was found similar between the two years, while there was substantial difference for the high group. The findings are expected to lay a good foundation for developing remedy measures in the areas with low bud burst percentage, thus in turn improving the overall grape yield and quality. PMID:27798692

Effect of Simulated Anthonomus signatus (Coleoptera: Curculionidae) Injury on Strawberries (Fragaria × ananassa) Grown in Southeastern Plasticulture Production.

PubMed

McPhie, Douglas; Burrack, Hannah J

2017-02-01

Female strawberry bud weevils (Anthonomus signatus Say) oviposit in developing flower buds of strawberries (Fragaria spp.), caneberries (Rubus spp.), and red bud (Cercis canadensis). After laying a single egg, weevils will girdle or "clip" the buds at the pedicel, killing the bud and preventing fruit development. This injury is of concern to commercial strawberry growers, who typically assume the loss of one clipped bud is the loss of one average sized fruit, causing the economic threshold to be set extremely low. There is evidence of compensation in some cultivars of strawberries, but research has previously only been conducted in perennial strawberry production. The majority of strawberries in the southeastern United States are grown in annual plasticulture systems. We assessed the ability of five strawberry cultivars commonly grown in annual plasticulture to compensate for A. signatus injury by removing buds at different growth stages. There was no effect of bud removal on total yield in any of the cultivars tested. Harvest timing was affected by simulated A. signatus damage in some cultivars, which may be an important consideration for direct market strawberry growers. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Pleiotropic functions of embryonic sonic hedgehog expression link jaw and taste bud amplification with eye loss during cavefish evolution.

PubMed

Yamamoto, Yoshiyuki; Byerly, Mardi S; Jackman, William R; Jeffery, William R

2009-06-01

This study addresses the role of sonic hedgehog (shh) in increasing oral-pharyngeal constructive traits (jaws and taste buds) at the expense of eyes in the blind cavefish Astyanax mexicanus. In cavefish embryos, eye primordia degenerate under the influence of hyperactive Shh signaling. In concert, cavefish show amplified jaw size and taste bud numbers as part of a change in feeding behavior. To determine whether pleiotropic effects of hyperactive Shh signaling link these regressive and constructive traits, shh expression was compared during late development of the surface-dwelling (surface fish) and cave-dwelling (cavefish) forms of Astyanax. After an initial expansion along the midline of early embryos, shh was elevated in the oral-pharyngeal region in cavefish and later was confined to taste buds. The results of shh inhibition and overexpression experiments indicate that Shh signaling has an important role in oral and taste bud development. Conditional overexpression of an injected shh transgene at specific times in development showed that taste bud amplification and eye degeneration are sensitive to shh overexpression during the same early developmental period, although taste buds are not formed until much later. Genetic crosses between cavefish and surface fish revealed an inverse relationship between eye size and jaw size/taste bud number, supporting a link between oral-pharyngeal constructive traits and eye degeneration. The results suggest that hyperactive Shh signaling increases oral and taste bud amplification in cavefish at the expense of eyes. Therefore, selection for constructive oral-pharyngeal traits may be responsible for eye loss during cavefish evolution via pleiotropic function of the Shh signaling pathway.

Twilight far-red treatment advances leaf bud burst of silver birch (Betula pendula).

PubMed

Linkosalo, Tapio; Lechowicz, Martin J

2006-10-01

Bud development of boreal trees in spring, once initiated, is driven by ambient air temperature, but the mechanism triggering bud development remains unclear. We determined if some aspect of the diurnal or seasonal light regime influences initiation of bud burst once the chilling requirement is met. We grew 3-year-old birch plantlets cloned from a mature tree of boreal origin in light conditions realistically simulating the lengthening days of spring at 60 degrees N. To emulate the reduction in red to far-red light (R:FR) ratio between daylight and twilight, one group of plantlets was subjected to reduced R:FR ratio in the morning and evening in addition to progressively lengthening days, whereas the other group was subjected to the same R:FR ratio throughout the day. The reduced R:FR ratio of twilight advanced bud burst by 4 days compared with the reference group (P = 0.04). To assess the interplay between the fulfillment of the chilling requirement and the subsequent response to warming, we fitted a thermal time model to the data with separate parameterizations for the starting dates of heat sum accumulation in each treatment. Least-squares fitting suggested that bud development started in light regimes corresponding to late March, almost two months after the chilling requirement for dormancy release was satisfied. Therefore, shortening night length or increasing day length, or both, appears to be the cue enabling bud development in spring, with twilight quality having an effect on the photoperiodic response. If twilight alone were the cue, the difference in bud burst dates between the experimental groups would have been greater than 4 days. The result gives experimental support for the use of thermal-time models in phenological modeling.

How and why does the areole meristem move in Echinocereus (Cactaceae)?

PubMed

Sánchez, Daniel; Grego-Valencia, Dalia; Terrazas, Teresa; Arias, Salvador

2015-01-01

In Cactaceae, the areole is the organ that forms the leaves, spines and buds. Apparently, the genus Echinocereus develops enclosed buds that break through the epidermis of the stem adjacent to the areole; this trait most likely represents a synapomorphy of Echinocereus. The development of the areole is investigated here in order to understand the anatomical modifications that lead to internal bud development and to supplement anatomical knowledge of plants that do not behave according to classical shoot theory. The external morphology of the areole was documented and the anatomy was studied using tissue clearing, scanning electron microscopy and light microscopy for 50 species that represent the recognized clades and sections of the traditional classification of the genus, including Morangaya pensilis (Echinocereus pensilis). In Echinocereus, the areole is sealed by the periderm, and the areole meristem is moved and enclosed by the differential growth of the epidermis and surrounding cortex. The enclosed areole meristem is differentiated in a vegetative or floral bud, which develops internally and breaks through the epidermis of the stem. In Morangaya pensilis, the areole is not sealed by the periderm and the areole meristem is not enclosed. The enclosed areole meristem and internal bud development are understood to be an adaptation to protect the meristem and the bud from low temperatures. The anatomical evidence supports the hypothesis that the enclosed bud represents one synapomorphy for Echinocereus and also supports the exclusion of Morangaya from Echinocereus. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ontogeny and innervation of taste buds in mouse palatal gustatory epithelium.

PubMed

Rashwan, Ahmed; Konishi, Hiroyuki; El-Sharaby, Ashraf; Kiyama, Hiroshi

2016-01-01

We investigated the relationship between mouse taste bud development and innervation of the soft palate. We employed scanning electron microscopy and immunohistochemistry using antibodies against protein gene product 9.5 and peripherin to detect sensory nerves, and cytokeratin 8 and α-gustducin to stain palatal taste buds. At E14, nerve fibers were observed along the medial border of the palatal shelves that tracked toward the epithelium. At E15.5, primordial stages of taste buds in the basal lamina of the soft palate first appeared. At E16, the taste buds became large spherical masses of columnar cells scattered in the soft palate basal lamina. At E17, the morphology and also the location of taste buds changed. At E18-19, some taste buds acquired a more elongated shape with a short neck, extending a variable distance from the soft palate basal lamina toward the surface epithelium. At E18, mature taste buds with taste pores and perigemmal nerve fibers were observed on the surface epithelium of the soft palate. The expression of α-gustducin was demonstrated at postnatal day 1 and the number of pored taste buds increased with age and they became pear-shaped at 8 weeks. The percent of pored fungiform-like papillae at birth was 58.3% of the whole palate; this increased to 83.8% at postnatal day 8 and reached a maximum of 95.7% at 12 weeks. The innervation of the soft palate was classified into three types of plexuses in relation to taste buds: basal nerve plexus, intragemmal and perigemmal nerve fibers. This study reveals that the nerve fibers preceded the development of taste buds in the palate of mice, and therefore the nerve fibers have roles in the initial induction of taste buds in the soft palate. Copyright © 2015 Elsevier B.V. All rights reserved.

A unique approach to demonstrating that apical bud temperature specifically determines leaf initiation rate in the dicot Cucumis sativus.

PubMed

Savvides, Andreas; Dieleman, Janneke A; van Ieperen, Wim; Marcelis, Leo F M

2016-04-01

Leaf initiation rate is largely determined by the apical bud temperature even when apical bud temperature largely deviates from the temperature of other plant organs. We have long known that the rate of leaf initiation (LIR) is highly sensitive to temperature, but previous studies in dicots have not rigorously demonstrated that apical bud temperature controls LIR independent of other plant organs temperature. Many models assume that apical bud and leaf temperature are the same. In some environments, the temperature of the apical bud, where leaf initiation occurs, may differ by several degrees Celsius from the temperature of other plant organs. In a 28-days study, we maintained temperature differences between the apical bud and the rest of the individual Cucumis sativus plants from -7 to +8 °C by enclosing the apical buds in transparent, temperature-controlled, flow-through, spheres. Our results demonstrate that LIR was completely determined by apical bud temperature independent of other plant organs temperature. These results emphasize the need to measure or model apical bud temperatures in dicots to improve the prediction of crop development rates in simulation models.

Transcriptome analyses based on genetic screens for Pax3 myogenic targets in the mouse embryo

PubMed Central

2010-01-01

Background Pax3 is a key upstream regulator of the onset of myogenesis, controlling progenitor cell survival and behaviour as well as entry into the myogenic programme. It functions in the dermomyotome of the somite from which skeletal muscle derives and in progenitor cell populations that migrate from the somite such as those of the limbs. Few Pax3 target genes have been identified. Identifying genes that lie genetically downstream of Pax3 is therefore an important endeavour in elucidating the myogenic gene regulatory network. Results We have undertaken a screen in the mouse embryo which employs a Pax3GFP allele that permits isolation of Pax3 expressing cells by flow cytometry and a Pax3PAX3-FKHR allele that encodes PAX3-FKHR in which the DNA binding domain of Pax3 is fused to the strong transcriptional activation domain of FKHR. This constitutes a gain of function allele that rescues the Pax3 mutant phenotype. Microarray comparisons were carried out between Pax3GFP/+ and Pax3GFP/PAX3-FKHR preparations from the hypaxial dermomyotome of somites at E9.5 and forelimb buds at E10.5. A further transcriptome comparison between Pax3-GFP positive and negative cells identified sequences specific to myogenic progenitors in the forelimb buds. Potential Pax3 targets, based on changes in transcript levels on the gain of function genetic background, were validated by analysis on loss or partial loss of function Pax3 mutant backgrounds. Sequences that are up- or down-regulated in the presence of PAX3-FKHR are classified as somite only, somite and limb or limb only. The latter should not contain sequences from Pax3 positive neural crest cells which do not invade the limbs. Verification by whole mount in situ hybridisation distinguishes myogenic markers. Presentation of potential Pax3 target genes focuses on signalling pathways and on transcriptional regulation. Conclusions Pax3 orchestrates many of the signalling pathways implicated in the activation or repression of myogenesis by regulating effectors and also, notably, inhibitors of these pathways. Important transcriptional regulators of myogenesis are candidate Pax3 targets. Myogenic determination genes, such as Myf5 are controlled positively, whereas the effect of Pax3 on genes encoding inhibitors of myogenesis provides a potential brake on differentiation. In the progenitor cell population, Pax7 and also Hdac5 which is a potential repressor of Foxc2, are subject to positive control by Pax3. PMID:21143873

Structural Characterization of Ginsenosides from Flower Buds of Panax ginseng by RRLC-Q-TOF MS.

PubMed

Wu, Wei; Lu, Ziyan; Teng, Yaran; Guo, Yingying; Liu, Shuying

2016-02-01

Ginseng flower bud as a part of Panax ginseng has received much attention as a valuable functional food with medicinal potential. A few studies focused on systematic and comprehensive studies on its major ingredients. This study aims to rapidly characterize ginsenosides in ginseng flower buds and provide scientific basis for developing functional food, exploiting pharmaceutical effects and making full use of ginseng resources. A rapid resolution liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (RRLC-Q-TOF-MS) method was developed for rapid qualitative and quantitative analysis of ginsenosides in ginseng flower buds. The compounds were identified by comparing retention time of the reference standards, accurate mass measurement and the fragment ions obtained from RRLC-Q-TOF-MS/MS analyses. A total of 14 kinds of ginsenosides were identified and 5 kinds of malonyl-ginsenosides were first tentatively identified in ginseng flower buds. Ten kinds of main ginsenosides were quantitatively analyzed. The developed RRLC-Q-TOF-MS method was demonstrated as an effective analytical means for rapid characterization of the ginsenosides in flower buds of P. ginseng. The research result is valuable for quality control, assessment of authenticity and stability evaluation of ginseng flower buds. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sox-2 in taste bud and lateral line system of zebrafish during development.

PubMed

Germanà, A; Montalbano, G; Guerrera, M C; Laura, R; Levanti, M; Abbate, F; de Carlos, F; Vega, J A; Ciriaco, E

2009-12-18

The Sox-2 is a transcription factor involved in adult neurogenesis in different vertebrate species, including fishes. Sox-2 also participates in growth and renewal on sensory cells in neuromasts of the fish lateral line system, and it is essential for development of taste buds in mammals. Using immunohistochemistry and Western blot we have investigated the occurrence and localization of Sox-2 taste buds and neuromast of zebrafish from 10 days post-fertilization to adult stage (1 year). The antibody used identifies two protein bands with estimated molecular weights of 34 and 37kDa which are consistent with those predicted for Sox-2. Sensory cells in taste buds displayed Sox-2 immunoreactivity at all the ages sampled, whereas in the neuromasts Sox-2 expression was restricted to the basal non-sensory cells. Interestingly Sox-2 immunoreactivity was observed in epithelial cells associated with both taste buds and neuromasts. Present results demonstrate that Sox-2 expressed in taste buds and neuromasts of zebrafish during the whole lifespan. Nevertheless, whereas the role of Sox-2 in taste buds of zebrafish remains to be established, the results in neuromast suggest that Sox-2 could participate in cell renewal of the mechanosensory cells.

Taste Bud-Derived BDNF Is Required to Maintain Normal Amounts of Innervation to Adult Taste Buds123

PubMed Central

Meng, Lingbin; Ohman-Gault, Lisa; Ma, Liqun

2015-01-01

Abstract Gustatory neurons transmit chemical information from taste receptor cells, which reside in taste buds in the oral cavity, to the brain. As adult taste receptor cells are renewed at a constant rate, nerve fibers must reconnect with new taste receptor cells as they arise. Therefore, the maintenance of gustatory innervation to the taste bud is an active process. Understanding how this process is regulated is a fundamental concern of gustatory system biology. We speculated that because brain-derived neurotrophic factor (BDNF) is required for taste bud innervation during development, it might function to maintain innervation during adulthood. If so, taste buds should lose innervation when Bdnf is deleted in adult mice. To test this idea, we first removed Bdnf from all cells in adulthood using transgenic mice with inducible CreERT2 under the control of the Ubiquitin promoter. When Bdnf was removed, approximately one-half of the innervation to taste buds was lost, and taste buds became smaller because of the loss of taste bud cells. Individual taste buds varied in the amount of innervation each lost, and those that lost the most innervation also lost the most taste bud cells. We then tested the idea that that the taste bud was the source of this BDNF by reducing Bdnf levels specifically in the lingual epithelium and taste buds. Taste buds were confirmed as the source of BDNF regulating innervation. We conclude that BDNF expressed in taste receptor cells is required to maintain normal levels of innervation in adulthood. PMID:26730405

Taste Bud-Derived BDNF Is Required to Maintain Normal Amounts of Innervation to Adult Taste Buds.

PubMed

Meng, Lingbin; Ohman-Gault, Lisa; Ma, Liqun; Krimm, Robin F

2015-01-01

Gustatory neurons transmit chemical information from taste receptor cells, which reside in taste buds in the oral cavity, to the brain. As adult taste receptor cells are renewed at a constant rate, nerve fibers must reconnect with new taste receptor cells as they arise. Therefore, the maintenance of gustatory innervation to the taste bud is an active process. Understanding how this process is regulated is a fundamental concern of gustatory system biology. We speculated that because brain-derived neurotrophic factor (BDNF) is required for taste bud innervation during development, it might function to maintain innervation during adulthood. If so, taste buds should lose innervation when Bdnf is deleted in adult mice. To test this idea, we first removed Bdnf from all cells in adulthood using transgenic mice with inducible CreERT2 under the control of the Ubiquitin promoter. When Bdnf was removed, approximately one-half of the innervation to taste buds was lost, and taste buds became smaller because of the loss of taste bud cells. Individual taste buds varied in the amount of innervation each lost, and those that lost the most innervation also lost the most taste bud cells. We then tested the idea that that the taste bud was the source of this BDNF by reducing Bdnf levels specifically in the lingual epithelium and taste buds. Taste buds were confirmed as the source of BDNF regulating innervation. We conclude that BDNF expressed in taste receptor cells is required to maintain normal levels of innervation in adulthood.

Factors influencing axillary shoot proliferation and adventitious budding in cedar.

PubMed

Renau-Morata, Begoña; Ollero, Javier; Arrillaga, Isabel; Segura, Juan

2005-04-01

We developed procedures for in vitro cloning of Cedrus atlantica Manetti and C. libani A. Rich explants from juvenile and mature plants. Explant size was one determinant of the frequency of axillary bud break in both species. Shoot tips and nodal explants mainly developed calli, whereas bud sprouting occurred in defoliated microcuttings cultured on a modified Murashige and Skoog medium without growth regulators. Isolation and continuous subculture of sprouted buds on the same medium allowed cloning of microcuttings from C. atlantica and C. libani seedlings and bicentennial C. libani trees, thus providing a desirable alternative for multiplying mature trees that have demonstrated superior characteristics. We also report adventitious bud differentiation from isolated embryos of C. atlantica. Neither auxin treatments nor other methods tested, including infection with Agrobacterium rhizogenes, were effective in inducing root initiation.

Development of the shoulder girdle musculature.

PubMed

Pu, Qin; Huang, Ruijin; Brand-Saberi, Beate

2016-03-01

The muscles of the shoulder region are important for movements of the upper limbs and for stabilizing the girdle elements by connecting them to the trunk. They have a triple embryonic origin. First, the branchiomeric shoulder girdle muscles (sternocleidomastoideus and trapezius muscles) develop from the occipital lateral plate mesoderm using Tbx1 over the course of this development. The second population of cells constitutes the superficial shoulder girdle muscles (pectoral and latissimus dorsi muscles), which are derived from the wing premuscle mass. This muscle group undergoes a two-step development, referred to as the "in-out" mechanism. Myogenic precursor cells first migrate anterogradely into the wing bud. Subsequently, they migrate in a retrograde manner from the wing premuscle mass to the trunk. SDF-1/CXCR4 signaling is involved in this outward migration. A third group of shoulder muscles are the rhomboidei and serratus anterior muscles, which are referred to as deep shoulder girdle muscles; they are thought to be derived from the myotomes. It is, however, not clear how myotome cells make contact to the scapula to form these two muscles. In this review, we discuss the development of the shoulder girdle muscle in relation to the different muscle groups. © 2015 Wiley Periodicals, Inc.

Neural crest contribution to lingual mesenchyme, epithelium and developing taste papillae and taste buds

PubMed Central

Liu, Hong-Xiang; Komatsu, Yoshihiro; Mishina, Yuji; Mistretta, Charlotte M.

2012-01-01

The epithelium of mammalian tongue hosts most of the taste buds that transduce gustatory stimuli into neural signals. In the field of taste biology, taste bud cells have been described as arising from “local epithelium”, in distinction from many other receptor organs that are derived from neurogenic ectoderm including neural crest (NC). In fact, contribution of NC to both epithelium and mesenchyme in the developing tongue is not fully understood. In the present study we used two independent, well-characterized mouse lines, Wnt1-Cre and P0-Cre that express Cre recombinase in a NC-specific manner, in combination with two Cre reporter mouse lines, R26R and ZEG, and demonstrate a contribution of NC-derived cells to both tongue mesenchyme and epithelium including taste papillae and taste buds. In tongue mesenchyme, distribution of NC-derived cells is in close association with taste papillae. In tongue epithelium, labeled cells are observed in an initial scattered distribution and progress to a clustered pattern between papillae, and within papillae and early taste buds. This provides evidence for a contribution of NC to lingual epithelium. Together with previous reports for the origin of taste bud cells from local epithelium in postnatal mouse, we propose that NC cells migrate into and reside in the epithelium of the tongue primordium at an early embryonic stage, acquire epithelial cell phenotypes, and undergo cell proliferation and differentiation that is involved in the development of taste papillae and taste buds. Our findings lead to a new concept about derivation of taste bud cells that include a NC origin. PMID:22659543

The VACTERL Association as a disturbance of cell fate determination.

PubMed

Lubinsky, Mark

2015-11-01

Cases diagnosed as the VACTERL Association are heterogeneous, and can involve other associations arising from different developmental processes with midline effects. However, these often lack the classic radial ray anomalies that help make VACTERL distinct. A more specific association can be delineated based on teratogenic disturbances affecting vulnerabilities associated with the establishment of cell fate through positional information, with two basic weaknesses: (i) The midline, where topological properties such as reduced lateral information should make information losses more likely; (ii) Increased distal sensitivity at the end of a morphogen gradient in the limbs, where both duplications and deficiencies can arise from similar disturbances. Vertebral, cardiac, anal-rectal, and tracheo-esophaeal findings are primary midline derivatives. While the kidneys are bilateral, they can be influenced by the midline, although there may also be effects on the ureteral buds as distal structures. The pre-axial area is the most distal in limb development, giving radial/tibial deficiencies and duplications. Alternatively, spina bifida and orofacial clefts originate from bilateral structures that are less likely to be affected by problems with midline determination, explaining the rarity of these disorders with VACTERL. Suggested human genetic models typically involve the midline, but lack radial findings, and true Mendelian forms are rare. However, developmental genes such as Sonic Hedgehog may have a pathogenetic role without being causal. © 2015 Wiley Periodicals, Inc.

Phenological bud bank development of Bouteloua gracilis, Hesperostipa comata, and Pascopyrum smithii during drought in the Northern Great Plains

USDA-ARS?s Scientific Manuscript database

Vegetative reproduction in rangelands relies on tiller recruitment from belowground bud banks. Improved understanding of species-specific bud production and phenology would facilitate timing of aboveground management strategies. Twelve individual plants of the warm season grass (Bouteloua gracilis...

Shoot Morphogenesis Associated With Flowering in Populus deltoides (Salicaceae)

Treesearch

Cetin Yuceer; Samuel B. Land; Mark E. Kubiske; Richard L. Harkess

2003-01-01

Temporal and spatial formation and differentiation of axillary buds in developing shoots of mature eastern cottonwood (Populus deltoides) were investigated. Shoots sequentially initiate early vegetative, floral, and late vegetative buds. Associated with these buds is the formation of three distinct leaf types. In May of the first growing season, the...

The heartstrings mutation in zebrafish causes heart/fin Tbx5 deficiency syndrome.

PubMed

Garrity, Deborah M; Childs, Sarah; Fishman, Mark C

2002-10-01

Holt-Oram syndrome is one of the autosomal dominant human "heart-hand" disorders, with a combination of upper limb malformations and cardiac defects. Holt-Oram syndrome is caused by mutations in the TBX5 gene, a member of a large family of T-box transcription factors that play important roles in cell-type specification and morphogenesis. In a screen for mutations affecting zebrafish cardiac function, we isolated the recessive lethal mutant heartstrings, which lacks pectoral fins and exhibits severe cardiac dysfunction, beginning with a slow heart rate and progressing to a stretched, non-functional heart. We mapped and cloned the heartstrings mutation and find it to encode the zebrafish ortholog of the TBX5 gene. The heartstrings mutation causes premature termination at amino acid 316. Homozygous mutant embryos never develop pectoral fin buds and do not express several markers of early fin differentiation. The total absence of any fin bud differentiation distinguishes heartstrings from most other mutations that affect zebrafish fin development, suggesting that Tbx5 functions very early in the pectoral fin induction pathway. Moderate reduction of Tbx5 by morpholino causes fin malformations, revealing an additional early requirement for Tbx5 in coordinating the axes of fin outgrowth. The heart of heartstrings mutant embryos appears to form and function normally through the early heart tube stage, manifesting only a slight bradycardia compared with wild-type siblings. However, the heart fails to loop and then progressively deteriorates, a process affecting the ventricle as well as the atrium. Relative to mammals, fish require lower levels of Tbx5 to produce malformed appendages and display whole-heart rather than atrial-predominant cardiac defects. However, the syndromic deficiencies of tbx5 mutation are remarkably well retained between fish and mammals.

[Cloning and expression of Tbx3 gene in Siberian sturgeon, Acipenser baerii].

PubMed

Zhang, Hao; Fan, Chun-Xin; Song, Jia-Kun

2012-04-01

Tbx3, a member of the TBX2 subfamily of T-box gene family, encodes a transcription factor with a highly conserved DNA-binding domain, which called T-domain. Tbx3 is involved in morphogenesis and organogenesis in vertebrates, such as limb development, heart remodeling, and neural placode differentiation. In the present study, a full-length 2 908 bp Tbx3 cDNA from Acipenser baerii (AbTbx3) was obtained using RT-PCR and RACE technique, which includes a 2 166 bp complete open reading frame encoding a putative peptide of 721 amino acids. AbTbx3 shares 73.5% identity with its human homolog. Particularly, the DNA-binding domain of AbTbx3 shared 95.2% identity with human Tbx3. Phylogenetic analysis revealed that AbTbx3 was grouped with Tbx3s in other vertebrates, which were clustered with Tbx2s and separated from Tbx4/5s. The predicted secondary and three-dimensional structures of the T-domain of AbTbx3 were remarkably similar to human Tbx3. Through semi-quantity RT-PCR, the expression of AbTbx3 was first detected at blastula stage during Siberian sturgeon embryonic development, increased gradually, reached its peak at early tail-bud stage and then decreased slightly. In adult sturgeon, AbTbx3 was strongly expressed in eye, brain, gill, intestines, pectoral fin and pelvic fin, but not in liver, blood, heart, kidney and muscle. The whole mount in situ hybridization showed that AbTbx3 was mainly expressed in the otic vesicle, hindbrain, dorsal notochord, pineal organ and dorsal fin bud in the larvae of stage 37 and 43.

Release of Apical Dominance in Potato Tuber Is Accompanied by Programmed Cell Death in the Apical Bud Meristem[C][W

PubMed Central

Teper-Bamnolker, Paula; Buskila, Yossi; Lopesco, Yael; Ben-Dor, Shifra; Saad, Inbal; Holdengreber, Vered; Belausov, Eduard; Zemach, Hanita; Ori, Naomi; Lers, Amnon; Eshel, Dani

2012-01-01

Potato (Solanum tuberosum) tuber, a swollen underground stem, is used as a model system for the study of dormancy release and sprouting. Natural dormancy release, at room temperature, is initiated by tuber apical bud meristem (TAB-meristem) sprouting characterized by apical dominance (AD). Dormancy is shortened by treatments such as bromoethane (BE), which mimics the phenotype of dormancy release in cold storage by inducing early sprouting of several buds simultaneously. We studied the mechanisms governing TAB-meristem dominance release. TAB-meristem decapitation resulted in the development of increasing numbers of axillary buds with time in storage, suggesting the need for autonomous dormancy release of each bud prior to control by the apical bud. Hallmarks of programmed cell death (PCD) were identified in the TAB-meristems during normal growth, and these were more extensive when AD was lost following either extended cold storage or BE treatment. Hallmarks included DNA fragmentation, induced gene expression of vacuolar processing enzyme1 (VPE1), and elevated VPE activity. VPE1 protein was semipurified from BE-treated apical buds, and its endogenous activity was fully inhibited by a cysteinyl aspartate-specific protease-1-specific inhibitor N-Acetyl-Tyr-Val-Ala-Asp-CHO (Ac-YVAD-CHO). Transmission electron microscopy further revealed PCD-related structural alterations in the TAB-meristem of BE-treated tubers: a knob-like body in the vacuole, development of cytoplasmic vesicles, and budding-like nuclear segmentations. Treatment of tubers with BE and then VPE inhibitor induced faster growth and recovered AD in detached and nondetached apical buds, respectively. We hypothesize that PCD occurrence is associated with the weakening of tuber AD, allowing early sprouting of mature lateral buds. PMID:22362870

Cellular Factors Required for Lassa Virus Budding

PubMed Central

Urata, Shuzo; Noda, Takeshi; Kawaoka, Yoshihiro; Yokosawa, Hideyoshi; Yasuda, Jiro

2006-01-01

It is known that Lassa virus Z protein is sufficient for the release of virus-like particles (VLPs) and that it has two L domains, PTAP and PPPY, in its C terminus. However, little is known about the cellular factor for Lassa virus budding. We examined which cellular factors are used in Lassa virus Z budding. We demonstrated that Lassa Z protein efficiently produces VLPs and uses cellular factors, Vps4A, Vps4B, and Tsg101, in budding, suggesting that Lassa virus budding uses the multivesicular body pathway functionally. Our data may provide a clue to develop an effective antiviral strategy for Lassa virus. PMID:16571837

Effectiveness of Routine BCG Vaccination on Buruli Ulcer Disease: A Case-Control Study in the Democratic Republic of Congo, Ghana and Togo

PubMed Central

Phillips, Richard Odame; Phanzu, Delphin Mavinga; Beissner, Marcus; Badziklou, Kossi; Luzolo, Elysée Kalundieko; Sarfo, Fred Stephen; Halatoko, Wemboo Afiwa; Amoako, Yaw; Frimpong, Michael; Kabiru, Abass Mohammed; Piten, Ebekalisai; Maman, Issaka; Bidjada, Bawimodom; Koba, Adjaho; Awoussi, Koffi Somenou; Kobara, Basile; Nitschke, Jörg; Wiedemann, Franz Xaver; Kere, Abiba Banla; Adjei, Ohene; Löscher, Thomas; Fleischer, Bernhard; Bretzel, Gisela; Herbinger, Karl-Heinz

2015-01-01

Background The only available vaccine that could be potentially beneficial against mycobacterial diseases contains live attenuated bovine tuberculosis bacillus (Mycobacterium bovis) also called Bacillus Calmette-Guérin (BCG). Even though the BCG vaccine is still widely used, results on its effectiveness in preventing mycobacterial diseases are partially contradictory, especially regarding Buruli Ulcer Disease (BUD). The aim of this case-control study is to evaluate the possible protective effect of BCG vaccination on BUD. Methodology The present study was performed in three different countries and sites where BUD is endemic: in the Democratic Republic of the Congo, Ghana, and Togo from 2010 through 2013. The large study population was comprised of 401 cases with laboratory confirmed BUD and 826 controls, mostly family members or neighbors. Principal Findings After stratification by the three countries, two sexes and four age groups, no significant correlation was found between the presence of BCG scar and BUD status of individuals. Multivariate analysis has shown that the independent variables country (p = 0.31), sex (p = 0.24), age (p = 0.96), and presence of a BCG scar (p = 0.07) did not significantly influence the development of BUD category I or category II/III. Furthermore, the status of BCG vaccination was also not significantly related to duration of BUD or time to healing of lesions. Conclusions In our study, we did not observe significant evidence of a protective effect of routine BCG vaccination on the risk of developing either BUD or severe forms of BUD. Since accurate data on BCG strains used in these three countries were not available, no final conclusion can be drawn on the effectiveness of BCG strain in protecting against BUD. As has been suggested for tuberculosis and leprosy, well-designed prospective studies on different existing BCG vaccine strains are needed also for BUD. PMID:25569674

Effect of pretreatment methods of dormant pear buds on viability after cryopreservation

USDA-ARS?s Scientific Manuscript database

This study aimed to develop alternatives for dormant bud cryopreservation by using several cryoprotectants on four pear cultivars with a view to improve the viability of the dormant buds. We used different cryoprotectants such as Honey, PVS2, PVS3, PVS4, Towill, IPBB-1 for cultivars: Talgarskaya Kra...

Bud structure, position and fate generate various branching patterns along shoots of closely related Rosaceae species: a review

PubMed Central

Costes, Evelyne; Crespel, Laurent; Denoyes, Béatrice; Morel, Philippe; Demene, Marie-Noëlle; Lauri, Pierre-Eric; Wenden, Bénédicte

2014-01-01

Branching in temperate plants is closely linked to bud fates, either floral or vegetative. Here, we review how the fate of meristematic tissues contained in buds and their position along a shoot imprint specific branching patterns which differ among species. Through examples chosen in closely related species in different genera of the Rosaceae family, a panorama of patterns is apparent. Patterns depend on whether vegetative and floral buds are borne individually or together in mixed buds, develop as the shoot grows or after a rest period, and are located in axillary or terminal positions along the parent shoot. The resulting branching patterns are conserved among varieties in a given species but progressively change with the parent shoot length during plant ontogeny. They can also be modulated by agronomic and environmental conditions. The existence of various organizations in the topology and fate of meristematic tissues and their appendages in closely related species questions the between-species conservation of physiological and molecular mechanisms leading to bud outgrowth vs. quiescence and to floral induction vs. vegetative development. PMID:25520729

NOGGIN IS REQUIRED FOR NORMAL LOBE PATTERNING AND DUCTAL BUDDING IN THE MOUSE PROSTATE

PubMed Central

Cook, Crist; Vezina, Chad M.; Hicks, Sarah M.; Shaw, Aubie; Yu, Min; Peterson, Richard E.; Bushman, Wade

2008-01-01

Mesenchymal expression of the BMP antagonist NOGGIN during prostate development plays a critical role in pre-natal ventral prostate development and opposes BMP4-mediated inhibition of cell proliferation during postnatal ductal development. Morphologic examination of newborn Noggin-/- male fetuses revealed genitourinary anomalies including cryptorchidism, incomplete separation of the hindgut from the urogenital sinus (UGS), absence of the ventral mesenchymal pad and a complete loss of ventral prostate (VP) budding. Examination of lobe-specific marker expression in the E14 Noggin-/- UGS rescued by transplantation under the renal capsule of a male nude mouse confirmed a complete loss of VP determination. More modest effects were observed in the other lobes, including decreased number of ductal buds in the dorsal and lateral prostates of newborn Noggin-/- males. BMP4 and BMP7 have been shown to inhibit ductal budding and outgrowth by negatively regulating epithelial cell proliferation. We show here that NOGGIN can neutralize budding inhibition by BMP4 and rescues branching morphogenesis of BMP4-exposed UGS in organ culture and show that the effects of BMP4 and NOGGIN activities converge on P63+ epithelial cells located at nascent duct tips. Together, these studies show that the BMP-NOGGIN axis regulates patterning of the ventral prostate, regulates ductal budding, and controls proliferation of P63+ epithelial cells in the nascent ducts of developing mouse prostate. PMID:18028901

Partial shoot reiteration in Wollemia nobilis (Araucariaceae) does not arise from ‘axillary meristems’

PubMed Central

Tomlinson, P. B.; Huggett, Brett A.

2011-01-01

Background and Aims Conifers are characterized by the paucity of axillary buds which in dicotyledonous trees usually occur at every node. To compensate, conifers also produce ‘axillary meristems’, which may be stimulated to late development. In juvenile material of Wollemia nobilis (Araucariaceae: Massart's model) first-order (plagiotropic) branches lack both axillary buds and, seemingly, axillary meristems. This contrasts with orthotropic (trunk) axes, which produce branches, either within the terminal bud or as reiterated orthotropic axes originating from axillary meristems. However, plagiotropic axes do produce branches if they are decapitated. This study investigated how this can occur if axillary meristems are not the source. Methods The terminal buds of a series of plagiotropic branches on juvenile trees were decapitated in order to generate axillary shoots. Shoots were culled at about weekly intervals to obtain stages in lateral shoot development. Serial sections were cut with a sliding microtome from the distal end of each sample and scanned sequentially for evidence of axillary meristems and early bud development. Key Results Anatomical search produced no clear evidence of pre-existing axillary meristems but did reveal stages of bud initiation. Buds were initiated in a group of small starch-rich cortical cells. Further development involved de-differentiation of these small cells and the development of contrasting outer and inner regions. The outer part becomes meristematic and organizes the apex of the new branch. The inner part develops a callus-like tissue of vacuolated cells within which vascular cambia are developed. This kind of insertion of a branch on the parent axis seems not to have been described before. Conclusions Axillary meristems in Wollemia characterize the leaf axils of trunk axes so that the origin of reiterated shoots is clear. Plagiotropic axes seemingly lack axillary meristems but still produce axillary branches by distinctive developmental processes. These observations demonstrate limited understanding of branch initiation in trees generally. PMID:21335327

Aberrant pulmonary lymphatic development in the nitrofen mouse model of congenital diaphragmatic hernia

PubMed Central

Shue, Eveline; Wu, Jianfeng; Schecter, Samuel; Miniati, Doug

2013-01-01

Purpose Many infants develop a postsurgical chylothorax after diaphragmatic hernia repair. The pathogenesis remains elusive but may be due to dysfunctional lymphatic development. This study characterizes pulmonary lymphatic development in the nitrofen mouse model of CDH. Methods CD1 pregnant mice were fed nitrofen/bisdiamine (N/B) or olive oil at E8.5. At E14.5 and E15.5, lung buds were categorized by phenotype: normal, N/B without CDH (N/B−CDH), or N/B with CDH (N/B+CDH). Anti-CD31 was used to localize all endothelial cells, while anti-LYVE-1 was used to identify lymphatic endothelial cells in lung buds using immunofluorescence. Differential protein expression of lymphatic-specific markers was analyzed. Results Lymphatic endothelial cells localized to the mesenchyme surrounding the airway epithelium at E15.5. CD31 and LYVE-1 colocalization identified lymphatic endothelial cells. LYVE-1 expression was upregulated in N/B+CDH lung buds in comparison to N/B−CDH and normal lung buds by immunofluorescence. Western blotting shows that VEGF-D, LYVE-1, Prox-1, and VEGFR-3 expression was upregulated in N/B+CDH lung buds in comparison to N/B−CDH or control lung buds at E14.5. Conclusions Lung lymphatics are hyperplastic in N/B+CDH. Upregulation of lymphatic-specific genes suggest that lymphatic hyperplasia plays an important role in dysfunctional lung lymphatic development in the nitrofen mouse model of CDH. PMID:23845607

Aberrant pulmonary lymphatic development in the nitrofen mouse model of congenital diaphragmatic hernia.

PubMed

Shue, Eveline; Wu, Jianfeng; Schecter, Samuel; Miniati, Doug

2013-06-01

Many infants develop a postsurgical chylothorax after diaphragmatic hernia repair. The pathogenesis remains elusive but may be owing to dysfunctional lymphatic development. This study characterizes pulmonary lymphatic development in the nitrofen mouse model of CDH. CD1 pregnant mice were fed nitrofen/bisdiamine (N/B) or olive oil at E8.5. At E14.5 and E15.5, lung buds were categorized by phenotype: normal, N/B without CDH (N/B - CDH), or N/B with CDH (N/B+CDH). Anti-CD31 was used to localize all endothelial cells, while anti-LYVE-1 was used to identify lymphatic endothelial cells in lung buds using immunofluorescence. Differential protein expression of lymphatic-specific markers was analyzed. Lymphatic endothelial cells localized to the mesenchyme surrounding the airway epithelium at E15.5. CD31 and LYVE-1 colocalization identified lymphatic endothelial cells. LYVE-1 expression was upregulated in N/B+CDH lung buds in comparison to N/B - CDH and normal lung buds by immunofluorescence. Western blotting shows that VEGF-D, LYVE-1, Prox-1, and VEGFR-3 expression was upregulated in N/B+CDH lung buds in comparison to N/B - CDH or control lung buds at E14.5. Lung lymphatics are hyperplastic in N/B+CDH. Upregulation of lymphatic-specific genes suggests that lymphatic hyperplasia plays an important role in dysfunctional lung lymphatic development in the nitrofen mouse model of CDH. Copyright © 2013 Elsevier Inc. All rights reserved.

Carbon gain and bud physiology in Populus tremuloides and Betula papyrifera grown under long-term exposure to elevated concentrations of CO2 and O3.

PubMed

Riikonen, Johanna; Kets, Katre; Darbah, Joseph; Oksanen, Elina; Sober, Anu; Vapaavuori, Elina; Kubiske, Mark E; Nelson, Neil; Karnosky, David F

2008-02-01

Paper birch (Betula papyrifera Marsh.) and three trembling aspen clones (Populus tremuloides Michx.) were studied to determine if alterations in carbon gain in response to an elevated concentration of CO(2) ([CO(2)]) or O(3) ([O(3)]) or a combination of both affected bud size and carbohydrate composition in autumn, and early leaf development in the following spring. The trees were measured for gas exchange, leaf size, date of leaf abscission, size and biochemical characteristics of the overwintering buds and early leaf development during the 8th-9th year of free-air CO(2) and O(3) exposure at the Aspen FACE site located near Rhinelander, WI. Net photosynthesis was enhanced 49-73% by elevated [CO(2)], and decreased 13-30% by elevated [O(3)]. Elevated [CO(2)] delayed, and elevated [O(3)] tended to accelerate, leaf abscission in autumn. Elevated [CO(2)] increased the ratio of monosaccharides to di- and oligosaccharides in aspen buds, which may indicate a lag in cold acclimation. The total carbon concentration in overwintering buds was unaffected by the treatments, although elevated [O(3)] decreased the amount of starch by 16% in birch buds, and reduced the size of aspen buds, which may be related to the delayed leaf development in aspen during the spring. Elevated [CO(2)] generally ameliorated the effects of elevated [O(3)]. Our results show that both elevated [CO(2)] and elevated [O(3)] have the potential to alter carbon metabolism of overwintering buds. These changes may cause carry-over effects during the next growing season.

Neural crest contribution to lingual mesenchyme, epithelium and developing taste papillae and taste buds.

PubMed

Liu, Hong-Xiang; Komatsu, Yoshihiro; Mishina, Yuji; Mistretta, Charlotte M

2012-08-15

The epithelium of mammalian tongue hosts most of the taste buds that transduce gustatory stimuli into neural signals. In the field of taste biology, taste bud cells have been described as arising from "local epithelium", in distinction from many other receptor organs that are derived from neurogenic ectoderm including neural crest (NC). In fact, contribution of NC to both epithelium and mesenchyme in the developing tongue is not fully understood. In the present study we used two independent, well-characterized mouse lines, Wnt1-Cre and P0-Cre that express Cre recombinase in a NC-specific manner, in combination with two Cre reporter mouse lines, R26R and ZEG, and demonstrate a contribution of NC-derived cells to both tongue mesenchyme and epithelium including taste papillae and taste buds. In tongue mesenchyme, distribution of NC-derived cells is in close association with taste papillae. In tongue epithelium, labeled cells are observed in an initial scattered distribution and progress to a clustered pattern between papillae, and within papillae and early taste buds. This provides evidence for a contribution of NC to lingual epithelium. Together with previous reports for the origin of taste bud cells from local epithelium in postnatal mouse, we propose that NC cells migrate into and reside in the epithelium of the tongue primordium at an early embryonic stage, acquire epithelial cell phenotypes, and undergo cell proliferation and differentiation that is involved in the development of taste papillae and taste buds. Our findings lead to a new concept about derivation of taste bud cells that include a NC origin. Copyright © 2012 Elsevier Inc. All rights reserved.

Sall1-dependent signals affect Wnt signaling and ureter tip fate to initiate kidney development.

PubMed

Kiefer, Susan M; Robbins, Lynn; Stumpff, Kelly M; Lin, Congxing; Ma, Liang; Rauchman, Michael

2010-09-01

Development of the metanephric kidney depends on precise control of branching of the ureteric bud. Branching events represent terminal bifurcations that are thought to depend on unique patterns of gene expression in the tip compared with the stalk and are influenced by mesenchymal signals. The metanephric mesenchyme-derived signals that control gene expression at the ureteric bud tip are not well understood. In mouse Sall1 mutants, the ureteric bud grows out and invades the metanephric mesenchyme, but it fails to initiate branching despite tip-specific expression of Ret and Wnt11. The stalk-specific marker Wnt9b and the beta-catenin downstream target Axin2 are ectopically expressed in the mutant ureteric bud tips, suggesting that upregulated canonical Wnt signaling disrupts ureter branching in this mutant. In support of this hypothesis, ureter arrest is rescued by lowering beta-catenin levels in the Sall1 mutant and is phenocopied by ectopic expression of a stabilized beta-catenin in the ureteric bud. Furthermore, transgenic overexpression of Wnt9b in the ureteric bud causes reduced branching in multiple founder lines. These studies indicate that Sall1-dependent signals from the metanephric mesenchyme are required to modulate ureteric bud tip Wnt patterning in order to initiate branching.

Transient etiolation: protochlorophyll(ide) and chlorophyll forms in differentiating plastids of closed and breaking leaf buds of horse chestnut (Aesculus hippocastanum).

PubMed

Solymosi, Katalin; Bóka, Károly; Böddi, Béla

2006-08-01

An accompanying paper reports the accumulation of photoactive protochlorophyllide (Pchlide) in the innermost leaf primordia of buds of many tree species. In this paper, we describe plastid differentiation, changes in pigment concentrations and spectral properties of bud scales and leaf primordia of horse chestnut (Aesculus hippocastanum L.) from January until the end of bud break in April. The bud scales contained plastids with grana, stroma thylakoids characteristic of chloroplasts and large dense bodies within the stroma. In January, proplastids and young chloroplasts were present in the leaf primordia, and the fluorescence spectra of the primordia were similar to those of green leaves except for a minor band at 630 nm, indicative of a protochlorophyll(ide). During bud break, the pigment concentrations of the green bud scales and the outermost leaf primordia increased, and Pchlide forms with emission maxima at 633, 644 and 655 nm accumulated in the middle and innermost leaf primordia. Depending on the position of the leaf primordia within the bud, their plastids and their pigment concentrations varied. Etio-chloroplasts with prolamellar bodies (PLBs) and prothylakoids with developing grana were observed in the innermost leaves. Besides the above-mentioned Pchlide forms, the middle and innnermost leaf primordia contained only a Chl band with an emission maximum at 686 nm. The outermost leaf primordia contained etio-chloroplasts with well-developed grana and small, narrow-type PLBs. These outermost leaves contained only chlorophyll forms like the mature green leaves. No Pchlide accumulation was observed after bud break, indicating that etiolation of the innermost and middle leaves is transient. The Pchlide forms and the plastid types of the primordia in buds grown in nature were similar to those of leaves of dark-germinated seedlings and to those of the leaf primordia of dark-forced buds. We conclude that transient etiolation occurs under natural conditions. The formation of PLBs and etio-chloroplasts and the accumulation of the light-dependent NADPH:protochlorophyllide oxidoreductase are involved in the natural greening process and ontogenesis of young leaf primordia of horse chestnut buds.

Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance

PubMed Central

Liu, H-X; Ermilov, A; Grachtchouk, M; Li, L; Gumucio, DL; Dlugosz, AA; Mistretta, CM

2014-01-01

The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste organs, the fungiform papilla and taste bud, and surrounding lingual cells. Shh signaling has roles in forming and maintaining fungiform papillae and taste buds, most likely via stage-specific autocrine and/or paracrine mechanisms, and by engaging epithelial/mesenchymal interactions. PMID:23916850

Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance.

PubMed

Liu, Hong Xiang; Ermilov, Alexandre; Grachtchouk, Marina; Li, Libo; Gumucio, Deborah L; Dlugosz, Andrzej A; Mistretta, Charalotte M

2013-10-01

The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste organs, the fungiform papilla and taste bud, and surrounding lingual cells. Shh signaling has roles in forming and maintaining fungiform papillae and taste buds, most likely via stage-specific autocrine and/or paracrine mechanisms, and by engaging epithelial/mesenchymal interactions. © 2013 Elsevier Inc. All rights reserved.

Apical bud toughness tests and tree sway movements to examine crown abrasion: preliminary results

Treesearch

Tyler Brannon; Wayne Clatterbuck

2012-01-01

Apical bud toughness differences were examined for several species to determine if crown abrasion affects shoot growth of determinate and indeterminate species during stand development. Determinate buds will set and harden after initial shoot elongation in the spring, while the indeterminate shoots form leaves from the apical meristem continuously based on the...

A Technique to Study Phenological Interactions between Douglas-Fir Buds and Emerging Second Instar Western Spruce Budworm

Treesearch

Roy F. Shepherd

1983-01-01

A technique is described to relate seasonal development of buds of Douglas-fir, Pseudotsuga menziesii (Mirt.) Franco, to larval emergence and survival of western spruce budworm (Choristoneura occidentalis Freeman) (Tortricidae). Losses of larvae due to asynchrony of emergence and bud swelling and the reduced protection of the...

Expression of the beta-catenin gene in the skin of embryonic geese during feather bud development.

PubMed

Wu, W; Xu, R F; Xiao, L; Xu, H; Gao, G

2008-01-01

beta-Catenin signaling has been reported to initiate feather bud development. In the present study, beta-catenin gene was isolated and identified from a cDNA library constructed using embryonic goose skin. Expression patterns of beta-catenin gene in the dorsal skin of goose embryos were investigated using the methods of semi-quantitative reverse transcription PCR, Northern blot analysis, and in situ hybridization. The sequence of beta-catenin was found highly conserved at the amino acid level, sharing 100, 99, and 99% identity with chicken, Chinese soft-shell turtle, and human sequences, respectively. Relatively high levels (62.51 +/- 7.11% to 101.74 +/- 7.29%) of beta-catenin mRNA were detected in the dorsal skin samples. The levels of beta-catenin expression were most prominent at the early stage from embryo day (E)10 to E20 and then significantly declined with the embryonic development. In situ hybridization demonstrated that at E10, beta-catenin expression was mainly observed at the surface periderm cells and the localized region of the epidermal layer. Because feather bud forms with an anterior-posterior orientation, strong staining was observed in the periderm layer and in the ectoderm and epidermis with a diffuse distribution within the internal area of the buds. The stronger staining was seen in the barb ridges than in the center pulp of the feather follicles at E18 and E20. In this study, expression of Shh as a marker gene for the bud development was examined paralleling with expression patterns of beta-catenin. It was found that the expression pattern of beta-catenin was almost similar spatially and temporally to that of Shh mRNA at the later stages of bud development. The differential beta-catenin mRNA expression in the goose dorsal skin may be essential for promoting the normal development of embryonic feather bud.

BudBurst Buddies: A New Tool for Engaging the Youngest Citizen Scientists

NASA Astrophysics Data System (ADS)

Gardiner, L. S.; Henderson, S.; Ward, D.

2010-12-01

BudBurst Buddies (www.budburstbuddies.org) introduces elementary school age children to the science of observing plants and the timing of phenological (life cycle) events. BudBurst Buddies is a new part of the Project BudBurst national citizen science initiative (www.budburst.org), which allows individuals to engage in the scientific process, contributing to a better understanding of climate change while increasing public awareness of phenology and the impacts of climate change on plants. As a first step towards engaging the next generation of citizen scientists, BudBurst Buddies provides the opportunity for children to gain experience with scientific research and increases awareness of how plants change throughout the year. Children can participate in BudBurst Buddies on their own, with their families, or in formal or informal education settings. Each child who participates creates a journal about a plant of his or her choosing, makes observations of the plant over the growing season and submits findings online, earning an official BudBurst Buddies certificate. An online storybook for kids tells how two children, Lily and Sage, observed plants in their neighborhood and became BudBurst Buddies. This presentation will provide an overview of the BudBurst Buddies newly developed resources. BudBurst Buddies is a part of Project BudBurst, a national citizen science program coordinated by the National Ecological Observatory Network (NEON) and the Chicago Botanic Garden. Funding for this resource was provided by NEON, NSF, NASA, and the National Geographic Education Foundation.

Bioengineered Tooth Buds Exhibit Features of Natural Tooth Buds.

PubMed

Smith, E E; Angstadt, S; Monteiro, N; Zhang, W; Khademhosseini, A; Yelick, P C

2018-06-01

Tooth loss is a significant health issue currently affecting millions of people worldwide. Artificial dental implants, the current gold standard tooth replacement therapy, do not exhibit many properties of natural teeth and can be associated with complications leading to implant failure. Here we propose bioengineered tooth buds as a superior alternative tooth replacement therapy. We describe improved methods to create highly cellularized bioengineered tooth bud constructs that formed hallmark features that resemble natural tooth buds such as the dental epithelial stem cell niche, enamel knot signaling centers, transient amplifying cells, and mineralized dental tissue formation. These constructs were composed of postnatal dental cells encapsulated within a hydrogel material that were implanted subcutaneously into immunocompromised rats. To our knowledge, this is the first report describing the use of postnatal dental cells to create bioengineered tooth buds that exhibit evidence of these features of natural tooth development. We propose future bioengineered tooth buds as a promising, clinically relevant tooth replacement therapy.

Mice expressing GFP and CreER in osteochondro progenitor cells in the periosteum.

PubMed

Kawanami, Aya; Matsushita, Takehiko; Chan, Yuk Yu; Murakami, Shunichi

2009-08-28

We generated Prx1CreER-GFP transgenic mice that express tamoxifen-inducible Cre recombinase and GFP under the control of a 2.4 kb Prx1 promoter. The transgene is expressed in osteochondro progenitor cells in the developing limb buds and in a subpopulation of periosteal cells that is closely associated with the cortical bone. GFP-expressing cells isolated from the diaphyses of long bones by cell sorting express multiple markers of periosteal cells, including Prx1, Fgf18, Tenascin-W, Periostin, and Thrombospondin 2. In addition, these cells undergo chondrogenic and osteogenic differentiation in culture upon induction. Cell fate analysis using the Rosa26 LacZ reporter indicated that transgene-expressing cells give rise to some of the chondrocytes and osteoblasts in the fracture callus. Collectively, these observations strongly suggest that the transgene-expressing cells are osteochondro progenitor cells in the periosteum. The established Prx1CreER-GFP mice would offer novel approaches for analyzing the functions of periosteal cells in vitro and in vivo.

DNA methylation/demethylation programming during peach flower bud dormancy release, development and blooming

USDA-ARS?s Scientific Manuscript database

Peach flower bud development undergoes a long, complex and temperature-dependent regulation process with cessation of growth in response to cool temperatures in late fall, a slow but gradual development during the chilling period in winter, and eventually blooming in early spring. It has been demon...

Pharyngeal arch deficiencies affect taste bud development in the circumvallate papilla with aberrant glossopharyngeal nerve formation.

PubMed

Okubo, Tadashi; Takada, Shinji

2015-07-01

The pharyngeal arches (PAs) generate cranial organs including the tongue. The taste placodes, formed in particular locations on the embryonic tongue surface, differentiate into taste buds harbored in distinct gustatory papillae. The developing tongue also has a complex supply of cranial nerves through each PA. However, the relationship between the PAs and taste bud development is not fully understood. Ripply3 homozygous mutant mice, which have impaired third/fourth PAs, display a hypoplastic circumvallate papilla and lack taste buds, although the taste placode is normally formed. Formation of the glossopharyngeal ganglia is defective and innervation toward the posterior tongue is completely missing in Ripply3 mutant embryos at E12.5. Moreover, the distribution of neuroblasts derived from the epibranchial placode is severely, but not completely, atenuated, and the neural crest cells are diminished in the third PA region of Ripply3 mutant embryos at E9.5-E10.5. In Tbx1 homozygous mutant embryos, which exhibit another type of deficiency in PA development, the hypoplastic circumvallate papilla is observed along with abnormal formation of the glossopharyngeal ganglia and severely impaired innervation. PA deficiencies affect multiple aspects of taste bud development, including formation of the cranial ganglia and innervation to the posterior tongue. © 2015 Wiley Periodicals, Inc.

Photosynthetic leaf area modulates tiller bud outgrowth in sorghum: Bud outgrowth is sensitive to leaf area

DOE PAGES

Kebrom, Tesfamichael H.; Mullet, John E.

2014-12-12

Shoot branches or tillers develop from axillary buds. The dormancy versus outgrowth fates of buds depends on genetic, environmental and hormonal signals. Defoliation inhibits bud outgrowth indicating the role of leaf-derived metabolic factors such as sucrose in bud outgrowth. In this study, the sensitivity of bud outgrowth to selective defoliation was investigated. At 6 d after planting (6 DAP), the first two leaves of sorghum were fully expanded and the third was partially emerged. Therefore, the leaves were selectively defoliated at 6 DAP and the length of the bud in the first leaf axil was measured at 8 DAP. Budmore » outgrowth was inhibited by defoliation of only 2 cm from the tip of the second leaf blade. The expression of dormancy and sucrose-starvation marker genes was up-regulated and cell cycle and sucrose-inducible genes was down-regulated during the first 24 h postdefoliation of the second leaf.At 48 h, the expression of these genes was similar to controls as the defoliated plant recovers. Our results demonstrate that small changes in photosynthetic leaf area affect the propensity of tiller buds for outgrowth. Therefore, variation in leaf area and photosynthetic activity should be included when integrating sucrose into models of shoot branching.« less

Luminal mitosis drives epithelial cell dispersal within the branching ureteric bud

PubMed Central

Packard, Adam; Georgas, Kylie; Michos, Odyssé; Riccio, Paul; Cebrian, Cristina; Combes, Alexander N.; Ju, Adler; Ferrer-Vaquer, Anna; Hadjantonakis, Anna-Katerina; Zong, Hui; Little, Melissa H.; Costantini, Frank

2013-01-01

Summary The ureteric bud is an epithelial tube that undergoes branching morphogenesis to form the renal collecting system. Though development of a normal kidney depends on proper ureteric bud morphogenesis, the cellular events underlying this process remain obscure. Here, we used time-lapse microscopy together with several genetic labeling methods to observe ureteric bud cell behaviors in developing mouse kidneys. We observed an unexpected cell behavior in the branching tips of the ureteric bud, which we term “mitosis-associated cell dispersal”. Pre-mitotic ureteric tip cells delaminate from the epithelium and divide within the lumen; while one daughter cell retains a basal process, allowing it to reinsert into the epithelium at the site of origin, the other daughter cell reinserts at a position one to three cell diameters away. Given the high rate of cell division in ureteric tips, this cellular behavior causes extensive epithelial cell rearrangements that may contribute to renal branching morphogenesis. PMID:24183650

[Compensation effect of cotton growth and development after soil salt content reduction at bud stage].

PubMed

Guo, Wen-Qi; Zhang, Pei-Tong; Li, Chun-Hong; Yin, Jian-Mei; Han, Xiao-Yong

2014-01-01

To elucidate the dynamic characteristics of cotton growth and development after soil salt content reduction (SD) at bud stage and its effect on yield formation, a pot experiment was conducted in which soil salt content was declined from 5 per thousand level to 2 per thousand level at cotton bud stage. The results showed that the plant height, biomass, total fruit branch and fruit node number, boll number, boll mass of cotton plants increased after soil salt content reduction at bud stage. The distribution proportions of biomass in root and boll decreased after soil salt content reduction, however, the distribution proportions of biomass in leaf, main stem and fruit branch were on the rise. The growth rate of cotton plant increased after soil salt content reduction. Plant dry matter accumulation rate of SD cotton exceeded CK cotton at 22 days after soil salt content reduction. The response of different organs of cotton plant were different to soil salt content reduction, the plant height was the earliest, followed by the fruit branch and fruit node formation, and the bud and boll were the latest, which indicated that the compensation effect of cotton growth and development after soil salt content reduction at bud stage firstly appeared on the formation and growth of new leaf, fruit branch and fruit node, and on this basis, gradually brought out yield compensation.

Photoperiod and temperature responses of bud swelling and bud burst in four temperate forest tree species.

PubMed

Basler, David; Körner, Christian

2014-04-01

Spring phenology of temperate forest trees is optimized to maximize the length of the growing season while minimizing the risk of freezing damage. The release from winter dormancy is environmentally mediated by species-specific responses to temperature and photoperiod. We investigated the response of early spring phenology to temperature and photoperiod at different stages of dormancy release in cuttings from four temperate tree species in controlled environments. By tracking bud development, we were able to identify the onset of bud swelling and bud growth in Acer pseudoplatanus L., Fagus sylvatica L., Quercus petraea (Mattuschka) Liebl. and Picea abies (L.) H. Karst. At a given early stage of dormancy release, the onset and duration of the bud swelling prior to bud burst are driven by concurrent temperature and photoperiod, while the maximum growth rate is temperature dependent only, except for Fagus, where long photoperiods also increased bud growth rates. Similarly, the later bud burst was controlled by temperature and photoperiod (in the photoperiod sensitive species Fagus, Quercus and Picea). We conclude that photoperiod is involved in the release of dormancy during the ecodormancy phase and may influence bud burst in trees that have experienced sufficient chilling. This study explored and documented the early bud swelling period that precedes and defines later phenological stages such as canopy greening in conventional phenological works. It is the early bud growth resumption that needs to be understood in order to arrive at a causal interpretation and modelling of tree phenology at a large scale. Classic spring phenology events mark visible endpoints of a cascade of processes as evidenced here.

Local adaptations and climate change: converging sensitivity of bud break in black spruce provenances.

PubMed

Rossi, Sergio

2015-07-01

Species with transcontinental distribution or spread over wide geographical regions develop populations with growth traits genetically adapted to the local climate. The aim of this study was to investigate the ecotypic sensitivity of bud break, a strong adaptive trait, to a changing environment. Six phenological phases of bud break were monitored daily on black spruce [Picea mariana (Mill.) BSP] seedlings submitted to different temperatures (12, 16 and 20 °C) and photoperiods (14, 18 and 22 h). Six provenances were tested in growth chambers, produced from seeds collected along the whole latitudinal range of the closed boreal forest in Quebec, Canada. Bud break lasted 13.3 days on average and occurred earlier in seedlings from colder sites. The annual temperature of the sites suitably tracked the clinal variation among ecotypes, providing a clear biological explanation for the environmental signal driving the adaptive divergence of populations to the local climate. Increasing temperature induced an earlier bud break according to a non-linear pattern with greater advancements observed between 12 and 16 °C. Photoperiod was significant, but sensitivity analysis indicated that its effect on bud break was marginal with respect to temperature. No interaction of provenance × treatment was observed, demonstrating an ecotypic convergence of the responses to both factors. Changes in the growing conditions could substantially modify the synchronization between bud phenology and climate, thus exposing the developing meristems of black spruce to frost damage. However, similar advancements of bud break could be expected in the different ecotypes subjected to warmer temperatures or longer day lengths.

The timing of bud break in warming conditions: variation among seven sympatric conifer species from Eastern Canada

NASA Astrophysics Data System (ADS)

Rossi, Sergio; Isabel, Nathalie

2017-11-01

Phenological changes are expected with the ongoing global warming, which could create mismatches in the growth patterns among sympatric species or create synchrony with insect herbivores. In this study, we performed a comparative assessment of the timings of bud break among seven conifer species of Eastern Canada by evaluating seedling development in growth chambers under different temperatures (16, 20 and 24 °C). Bud break occurred earliest in Larix laricina, while Pinus strobus and Pinus resinosa had the latest. Warmer conditions advanced bud break, with the greatest effects being observed at the lower temperatures. Mixed models estimated that one additional degree of temperature produced advancements of 5.3 and 2.1 days at 16 and 20 °C, respectively. The hypothesis of an asynchronous change between species under warming was demonstrated only for the last phenological phases (split buds and exposed shoots), and principally in pines. Abies balsamea showed changes in bud break comparable with the other species analysed, rejecting the hypothesis of mismatches under warmer conditions. The observed non-linear responses of the timings of bud break to warming suggest that the major changes in bud phenology should be expected at the lowest temperatures.

Immunoelectron microscopy in embryos.

PubMed

Sierralta, W D

2001-05-01

Immunogold labeling of proteins in sections of embryos embedded in acrylate media provides an important analytical tool when the resolving power of the electron microscope is required to define sites of protein function. The protocol presented here was established to analyze the role and dynamics of the activated protein kinase C/Rack1 regulatory system in the patterning and outgrowth of limb bud mesenchyme. With minor changes, especially in the composition of the fixative solution, the protocol should be easily adaptable for the postembedding immunogold labeling of any other antigen in tissues of embryos of diverse species. Quantification of the labeling can be achieved by using electron microscope systems capable of supporting digital image analysis. Copyright 2001 Academic Press.

Distribution, Innervation, and Cellular Organization of Taste Buds in the Sea Catfish, Plotosus japonicus.

PubMed

Nakamura, Tatsufumi; Matsuyama, Naoki; Kirino, Masato; Kasai, Masanori; Kiyohara, Sadao; Ikenaga, Takanori

2017-01-01

The gustatory system of the sea catfish Plotosus japonicus, like that of other catfishes, is highly developed. To clarify the details of the morphology of the peripheral gustatory system of Plotosus, we used whole-mount immunohistochemistry to investigate the distribution and innervation of the taste buds within multiple organs including the barbels, oropharyngeal cavity, fins (pectoral, dorsal, and caudal), and trunk. Labeled taste buds could be observed in all the organs examined. The density of the taste buds was higher along the leading edges of the barbels and fins; this likely increases the chance of detecting food. In all the fins, the taste buds were distributed in linear arrays parallel to the fin rays. Labeling of nerve fibers by anti-acetylated tubulin antibody showed that the taste buds within each sensory field are innervated in different ways. In the barbels, large nerve bundles run along the length of the organ, with fascicles branching off to innervate polygonally organized groups of taste buds. In the fins, nerve bundles run along the axis of fin rays to innervate taste buds lying in a line. In each case, small fascicles of fibers branch from large bundles and terminate within the basal portions of the taste buds. Serotonin immunohistochemistry demonstrated that most of the taste buds in all the organs examined contained disk-shaped serotonin-immunopositive cells in their basal region. This indicates a similar organization of the taste buds, in terms of the existence of serotonin-immunopositive basal cells, across the different sensory fields in this species. © 2017 S. Karger AG, Basel.

FgBud3, a Rho4-Interacting Guanine Nucleotide Exchange Factor, Is Involved in Polarity Growth, Cell Division and Pathogenicity of Fusarium graminearum.

PubMed

Zhang, Chengkang; Luo, Zenghong; He, Dongdong; Su, Li; Yin, Hui; Wang, Guo; Liu, Hong; Rensing, Christopher; Wang, Zonghua

2018-01-01

Rho GTPases are signaling macromolecules that are associated with developmental progression and pathogenesis of Fusarium graminearum . Generally, enzymatic activities of Rho GTPases are regulated by Rho GTPase guanine nucleotide exchange factors (RhoGEFs). In this study, we identified a putative RhoGEF encoding gene ( FgBUD3 ) in F. graminearum database and proceeded further by using a functional genetic approach to generate FgBUD3 targeted gene deletion mutant. Phenotypic analysis results showed that the deletion of FgBUD3 caused severe reduction in growth of FgBUD3 mutant generated during this study. We also observed that the deletion of FgBUD3 completely abolished sexual reproduction and triggered the production of abnormal asexual spores with nearly no septum in ΔFgbud3 strain. Further results obtained from infection assays conducted during this research revealed that the FgBUD3 defective mutant lost its pathogenicity on wheat and hence, suggests FgBud3 plays an essential role in the pathogenicity of F. graminearum . Additional, results derived from yeast two-hybrid assays revealed that FgBud3 strongly interacted with FgRho4 compared to the interaction with FgRho2, FgRho3, and FgCdc42. Moreover, we found that FgBud3 interacted with both GTP-bound and GDP-bound form of FgRho4. From these results, we subsequently concluded that, the Rho4-interacting GEF protein FgBud3 crucially promotes vegetative growth, asexual and sexual development, cell division and pathogenicity in F. graminearum .

Xylem development in prunus flower buds and the relationship to deep supercooling.

PubMed

Ashworth, E N

1984-04-01

Xylem development in eight Prunus species was examined and the relationship to deep supercooling assessed. Dormant buds of six species, P. armeniaca, P. avium, P. cerasus, P. persica, P. salicina, and P. sargentii deep supercooled. Xylem vessel elements were not observed within the dormant floral primordia of these species. Instead, discrete bundles containing procambial cells were observed. Vascular differentiation resumed and xylem continuity was established during the time that the capacity to deep supercool was lost. In P. serotina and P. virginiana, two species which do not supercool, xylem vessels ran the length of the inflorescence and presumably provided a conduit for the spread of ice into the bud. The results support the hypothesis that the lack of xylem continuity is an important feature of buds which deep supercool.

Sponge budding is a spatiotemporal morphological patterning process: Insights from synchrotron radiation-based x-ray microtomography into the asexual reproduction of Tethya wilhelma.

PubMed

Hammel, Jörg U; Herzen, Julia; Beckmann, Felix; Nickel, Michael

2009-09-08

Primary agametic-asexual reproduction mechanisms such as budding and fission are present in all non-bilaterian and many bilaterian animal taxa and are likely to be metazoan ground pattern characters. Cnidarians display highly organized and regulated budding processes. In contrast, budding in poriferans was thought to be less specific and related to the general ability of this group to reorganize their tissues. Here we test the hypothesis of morphological pattern formation during sponge budding. We investigated the budding process in Tethya wilhelma (Demospongiae) by applying 3D morphometrics to high resolution synchrotron radiation-based x-ray microtomography (SR-muCT) image data. We followed the morphogenesis of characteristic body structures and identified distinct morphological states which indeed reveal characteristic spatiotemporal morphological patterns in sponge bud development. We discovered the distribution of skeletal elements, canal system and sponge tissue to be based on a sequential series of distinct morphological states. Based on morphometric data we defined four typical bud stages. Once they have reached the final stage buds are released as fully functional juvenile sponges which are morphologically and functionally equivalent to adult specimens. Our results demonstrate that budding in demosponges is considerably more highly organized and regulated than previously assumed. Morphological pattern formation in asexual reproduction with underlying genetic regulation seems to have evolved early in metazoans and was likely part of the developmental program of the last common ancestor of all Metazoa (LCAM).

Sponge budding is a spatiotemporal morphological patterning process: Insights from synchrotron radiation-based x-ray microtomography into the asexual reproduction of Tethya wilhelma

PubMed Central

Hammel, Jörg U; Herzen, Julia; Beckmann, Felix; Nickel, Michael

2009-01-01

Background Primary agametic-asexual reproduction mechanisms such as budding and fission are present in all non-bilaterian and many bilaterian animal taxa and are likely to be metazoan ground pattern characters. Cnidarians display highly organized and regulated budding processes. In contrast, budding in poriferans was thought to be less specific and related to the general ability of this group to reorganize their tissues. Here we test the hypothesis of morphological pattern formation during sponge budding. Results We investigated the budding process in Tethya wilhelma (Demospongiae) by applying 3D morphometrics to high resolution synchrotron radiation-based x-ray microtomography (SR-μCT) image data. We followed the morphogenesis of characteristic body structures and identified distinct morphological states which indeed reveal characteristic spatiotemporal morphological patterns in sponge bud development. We discovered the distribution of skeletal elements, canal system and sponge tissue to be based on a sequential series of distinct morphological states. Based on morphometric data we defined four typical bud stages. Once they have reached the final stage buds are released as fully functional juvenile sponges which are morphologically and functionally equivalent to adult specimens. Conclusion Our results demonstrate that budding in demosponges is considerably more highly organized and regulated than previously assumed. Morphological pattern formation in asexual reproduction with underlying genetic regulation seems to have evolved early in metazoans and was likely part of the developmental program of the last common ancestor of all Metazoa (LCAM). PMID:19737392

Role of fibroblast growth factor receptor signaling in kidney development.

PubMed

Bates, Carlton M

2007-03-01

Fibroblast growth factor receptors (Fgfrs) are expressed in the ureteric bud and metanephric mesenchyme of the developing kidney. Furthermore, in vitro and in vivo studies have shown that exogenous fibroblast growth factors (Fgfs) increase growth and maturation of the metanephric mesenchyme and ureteric bud. Deletion of fgf7, fgf10, and fgfr2IIIb (the receptor isoform that binds Fgf7 and Fgf10) in mice lead to smaller kidneys with fewer collecting ducts and nephrons. Overexpression of a dominant negative receptor isoform in transgenic mice has revealed more striking defects including renal aplasia or severe dysplasia. Moreover, deletion of many fgf ligands and receptors in mice results in early embryonic lethality, making it difficult to determine their roles in kidney development. Recently, conditional targeting approaches revealed that deletion of fgf8 from the metanephric mesenchyme interrupts nephron formation. Furthermore, deletion of fgfr2 from the ureteric bud resulted in both ureteric bud branching and stromal mesenchymal patterning defects. Deletion of both fgfr1 and fgfr2 in the metanephric mesenchyme resulted in renal aplasia, characterized by defects in metanephric mesenchyme formation and initial ureteric bud elongation and branching. Thus, Fgfr signaling is critical for growth and patterning of all renal lineages at early and later stages of kidney development.

Epicormic buds in trees: a review of bud establishment, development and dormancy release

Treesearch

Andrew R. ​Meier; Michael R. Saunders; Charles H. Michler

2012-01-01

The formation of epicormic sprouts on the boles of trees is a phenomenon that has, until recently, been poorly understood. Renewed interest in the topic in the last two decades has led to significant advances in our knowledge of the subject, especially in regard to bud anatomy, morphology and ontogeny. There exists, however, no comprehensive synthesis of results from...

The epigenetic memory of temperature during embryogenesis modifies the expression of bud burst-related genes in Norway spruce epitypes.

PubMed

Carneros, Elena; Yakovlev, Igor; Viejo, Marcos; Olsen, Jorunn E; Fossdal, Carl Gunnar

2017-09-01

Epigenetic memory affects the timing of bud burst phenology and the expression of bud burst-related genes in genetically identical Norway spruce epitypes in a manner usually associated with ecotypes. In Norway spruce, a temperature-dependent epigenetic memory established during embryogenesis affects the timing of bud burst and bud set in a reproducible and predictable manner. We hypothesize that the clinal variation in these phenological traits, which is associated with adaptation to growth under frost-free conditions, has an epigenetic component. In Norway spruce, dehydrins (DHNs) have been associated with extreme frost tolerance. DHN transcript levels decrease gradually prior to flushing, a time when trees are highly sensitive to frost. Furthermore, EARLY BUD BREAK 1 genes (EBB1) and the FT-TFL1-LIKE 2-gene (PaFTL2) were previously suggested to be implied in control of bud phenology. Here we report an analysis of transcript levels of 12 DHNs, 3 EBB1 genes and FTL2 in epitypes of the same genotype generated at different epitype-inducing temperatures, before and during spring bud burst. Earlier flushing of epitypes originating from embryos developed at 18 °C as compared to 28 °C, was associated with differential expression of these genes between epitypes and between buds and last year's needles. The majority of these genes showed significantly different expressions between epitypes in at least one time point. The general trend in DHN expression pattern in buds showed the expected reduction in transcript levels when approaching flushing, whereas, surprisingly, transcript levels peaked later in needles, mainly at the moment of bud burst. Collectively, our results demonstrate that the epigenetic memory of temperature during embryogenesis affects bud burst phenology and expression of the bud burst-related DHN, EBB1 and FTL2 genes in genetically identical Norway spruce epitypes.

Red to Far-Red Light Ratio Modulates Hormonal and Genetic Control of Axillary bud Outgrowth in Chrysanthemum (Dendranthema grandiflorum 'Jinba').

PubMed

Yuan, Cunquan; Ahmad, Sagheer; Cheng, Tangren; Wang, Jia; Pan, Huitang; Zhao, Liangjun; Zhang, Qixiang

2018-05-28

Single-flower cut Chrysanthemum ( Dendranthema grandiflorum 'Jinba') holds a unique status in global floriculture industry. However, the extensive axillary bud outgrowth presents a major drawback. Shade is an environment cue that inhibits shoot branching. Present study was aimed at investigating the effect of ratio of red to far-red light (R:FR) in regulating the lateral bud outgrowth of Chrysanthemum and the detailed mechanism. Results showed that the fate of axillary buds at specific positions in stem exhibited difference in response to R:FR. Decreasing R:FR resulted in elevation of abscisic acid (ABA) accumulation in axillary buds. Expression of ABA, indole-3-acetic acid (IAA) and strigolactones (SL) -related metabolism and signal transduction genes was significantly changed in response to low R:FR. In addition, low R:FR caused the re-distribution of sucrose across the whole plant, driving more sucrose towards bottom buds. Our results indicate that low R:FR not always inhibits bud outgrowth, rather its influence depends on the bud position in the stem. ABA, SL and auxin pathways were involved in the process. Interestingly, sucrose also appears to be involved in the process which is necessary to pay attention in the further studies. The present study also lays the foundation for developing methods to regulate axillary bud outgrowth in Chrysanthemum.

Efficient transmission of cassava brown streak disease viral pathogens by chip bud grafting.

PubMed

Wagaba, Henry; Beyene, Getu; Trembley, Cynthia; Alicai, Titus; Fauquet, Claude M; Taylor, Nigel J

2013-12-06

Techniques to study plant viral diseases under controlled growth conditions are required to fully understand their biology and investigate host resistance. Cassava brown streak disease (CBSD) presents a major threat to cassava production in East Africa. No infectious clones of the causal viruses, Cassava brown streak virus (CBSV) or Ugandan cassava brown streak virus (UCBSV) are available, and mechanical transmission to cassava is not effective. An improved method for transmission of the viruses, both singly and as co-infections has been developed using bud grafts. Axillary buds from CBSD symptomatic plants infected with virulent isolates of CBSV and UCBSV were excised and grafted onto 6-8 week old greenhouse-grown, disease-free cassava plants of cultivars Ebwanateraka, TME204 and 60444. Plants were assessed visually for development of CBSD symptoms and by RT-PCR for presence of the viruses in leaf and storage root tissues. Across replicated experiments, 70-100% of plants inoculated with CBSV developed CBSD leaf and stem symptoms 2-6 weeks after bud grafting. Infected plants showed typical, severe necrotic lesions in storage roots at harvest 12-14 weeks after graft inoculation. Sequential grafting of buds from plants infected with UCBSV followed 10-14 days later by buds carrying CBSV, onto the same test plant, resulted in 100% of the rootstocks becoming co-infected with both pathogens. This dual transmission rate was greater than that achieved by simultaneous grafting with UCBSV and CBSV (67%), or when grafting first with CBSV followed by UCBSV (17%). The bud grafting method described presents an improved tool for screening cassava germplasm for resistance to CBSD causal viruses, and for studying pathogenicity of this important disease. Bud grafting provides new opportunities compared to previously reported top and side grafting systems. Test plants can be inoculated as young, uniform plants of a size easily handled in a small greenhouse or large growth chamber and can be inoculated in a controlled manner with CBSV and UCBSV, either singly or together. Disease symptoms develop rapidly, allowing better studies of interactions between these viral pathogens, their movement within shoot and root systems, and how they induce their destructive disease symptoms.

Redeployment of germ layers related TFs shows regionalized expression during two non-embryonic developments.

PubMed

Ricci, Lorenzo; Cabrera, Fabien; Lotito, Sonia; Tiozzo, Stefano

2016-08-01

In all non-vertebrate metazoan phyla, species that evolved non-embryonic developmental pathways as means of propagation or regeneration can be found. In this context, new bodies arise through asexual reproduction processes (such as budding) or whole body regeneration, that lack the familiar temporal and spatial cues classically associated with embryogenesis, like maternal determinants, or gastrulation. The molecular mechanisms underlying those non-embryonic developments (i.e., regeneration and asexual reproduction), and their relationship to those deployed during embryogenesis are poorly understood. We have addressed this question in the colonial ascidian Botryllus schlosseri, which undergoes an asexual reproductive process via palleal budding (PB), as well as a whole body regeneration by vascular budding (VB). We identified early regenerative structures during VB and then followed the fate of differentiating tissues during both non-embryonic developments (PB and VB) by monitoring the expression of genes known to play key functions in germ layer specification with well conserved expression patterns in solitary ascidian embryogenesis. The expression patterns of FoxA1, GATAa, GATAb, Otx, Bra, Gsc and Tbx2/3 were analysed during both PB and VB. We found that the majority of these transcription factors were expressed during both non-embryonic developmental processes, revealing a regionalization of the palleal and vascular buds. Knockdown of GATAa by siRNA in palleal buds confirmed that preventing the correct development of one of these regions blocks further tissue specification. Our results indicate that during both normal and injury-induced budding, a similar alternative developmental program operates via early commitment of epithelial regions. Copyright © 2016. Published by Elsevier Inc.

Characterizing early embryonic development of Brown Tsaiya Ducks (Anas platyrhynchos) in comparison with Taiwan Country Chicken (Gallus gallus domestics)

PubMed Central

Lumsangkul, Chompunut; Fan, Yang-Kwang; Chang, Shen-Chang; Ju, Jyh-Cherng

2018-01-01

Avian embryos are among the most convenient and the primary representatives for the study of classical embryology. It is well-known that the hatching time of duck embryos is approximately one week longer than that of chicken embryos. However, the key features associated with the slower embryonic development in ducks have not been adequately described. This study aimed to characterize the pattern and the speed of early embryogenesis in Brown Tsaiya Ducks (BTD) compared with those in Taiwan Country Chicken (TCC) by using growth parameters including embryonic crown-tail length (ECTL), primitive streak formation, somitogenesis, and other development-related parameters, during the first 72 h of incubation. Three hundred and sixty eggs from BTD and TCC, respectively, were incubated at 37.2°C, and were then dissected hourly to evaluate their developmental stages. We found that morphological changes of TCC embryos shared a major similarity with that of the Hamburger and Hamilton staging system during early chick embryogenesis. The initial primitive streak in TCC emerged between 6 and 7 h post-incubation, but its emergence was delayed until 10 to 13 h post-incubation in BTD. Similarly, the limb primordia (wing and limb buds) were observed at 51 h post-incubation in TCC embryos compared to 64 h post-incubation in BTD embryos. The allantois first appeared around 65 to 68 h in TCC embryos, but it was not observed in BTD embryos. At the 72 h post-incubation, 40 somites were clearly formed in TCC embryos while only 32 somites in BTD embryos. Overall, the BTD embryos developed approximately 16 h slower than the chicken embryo during the first 72 h of development. To our best knowledge, this is the first study to describe two distinct developmental time courses between TCC and BTD, which would facilitate future embryogenesis-related studies of the two important avian species in Taiwan. PMID:29742160

A 3D reconstruction of pancreas development in the human embryos during embryonic period (Carnegie stages 15-23).

PubMed

Radi, M; Gaubert, J; Cristol-Gaubert, R; Baecker, V; Travo, P; Prudhomme, M; Godlewski, G; Prat-Pradal, D

2010-01-01

The goal in this paper was to rebuild a three dimensional (3D) reconstruction of the dorsal and ventral pancreatic buds, in the human embryos, at Carnegie stages 15-23. The early development of the pancreas is studied by tissue observation and reconstruction by a computer-assisted method, using a light micrograph images from consecutive serial sagittal sections (diameter 7 microm) of ten human embryos ranging from Carnegie stages 15-23, CRL 7-27 mm, fixed, dehydrated and embedded in paraffin, were stained alternately with haematoxylin-eosin or Heindenhain'Azan. The images were digitalized by Canon Camera 350 EOS D. The serial views were aligned automatically by software, manual alignment was performed, the data were analysed following segmentation and threshold. The two buds were clearly identified at stage 15. In stage 16, both pancreatic buds were in final position, and begin to merge in stage 17. From stage 18 to the stage 23, surrounding connective tissue differentiated. In the stage 23, the morphology of the pancreas was definitive. The superior portion of the anterior face of the pancreas's head was arising from the dorsal bud. The rest of the head including the uncinate process emanated from the ventral bud. The 3D computer-assisted reconstruction of the human pancreas visualized the relationships between the two pancreatic buds. This explains the disposition and the modality of the components fusion. This embryologic development permits a better understanding of congenital abnormalities.

Transcriptome analysis of a spontaneous mutant in sweet orange [Citrus sinensis (L.) Osbeck] during fruit development.

PubMed

Liu, Qing; Zhu, Andan; Chai, Lijun; Zhou, Wenjing; Yu, Keqin; Ding, Jian; Xu, Juan; Deng, Xiuxin

2009-01-01

Bud mutations often arise in citrus. The selection of mutants is one of the most important breeding channels in citrus. However, the molecular basis of bud mutation has rarely been studied. To identify differentially expressed genes in a spontaneous sweet orange [C. sinensis (L.) Osbeck] bud mutation which causes lycopene accumulation, low citric acid, and high sucrose in fruit, suppression subtractive hybridization and microarray analysis were performed to decipher this bud mutation during fruit development. After sequencing of the differentially expressed clones, a total of 267 non-redundant transcripts were obtained and 182 (68.2%) of them shared homology (E-value < or = 1x10(-10)) with known gene products. Few genes were constitutively up- or down-regulated (fold change > or = 2) in the bud mutation during fruit development. Self-organizing tree algorithm analysis results showed that 95.1% of the differentially expressed genes were extensively coordinated with the initiation of lycopene accumulation. Metabolic process, cellular process, establishment of localization, response to stimulus, and biological regulation-related transcripts were among the most regulated genes. These genes were involved in many biological processes such as organic acid metabolism, lipid metabolism, transport, and pyruvate metabolism, etc. Moreover, 13 genes which were differentially regulated at 170 d after flowering shared homology with previously described signal transduction or transcription factors. The information generated in this study provides new clues to aid in the understanding of bud mutation in citrus.

Taste Bud Homeostasis in Health, Disease, and Aging

PubMed Central

2014-01-01

The mammalian taste bud is an onion-shaped epithelial structure with 50–100 tightly packed cells, including taste receptor cells, supporting cells, and basal cells. Taste receptor cells detect nutrients and toxins in the oral cavity and transmit the sensory information to gustatory nerve endings in the buds. Supporting cells may play a role in the clearance of excess neurotransmitters after their release from taste receptor cells. Basal cells are precursor cells that differentiate into mature taste cells. Similar to other epithelial cells, taste cells turn over continuously, with an average life span of about 8–12 days. To maintain structural homeostasis in taste buds, new cells are generated to replace dying cells. Several recent studies using genetic lineage tracing methods have identified populations of progenitor/stem cells for taste buds, although contributions of these progenitor/stem cell populations to taste bud homeostasis have yet to be fully determined. Some regulatory factors of taste cell differentiation and degeneration have been identified, but our understanding of these aspects of taste bud homoeostasis remains limited. Many patients with various diseases develop taste disorders, including taste loss and taste distortion. Decline in taste function also occurs during aging. Recent studies suggest that disruption or alteration of taste bud homeostasis may contribute to taste dysfunction associated with disease and aging. PMID:24287552

Taste bud homeostasis in health, disease, and aging.

PubMed

Feng, Pu; Huang, Liquan; Wang, Hong

2014-01-01

The mammalian taste bud is an onion-shaped epithelial structure with 50-100 tightly packed cells, including taste receptor cells, supporting cells, and basal cells. Taste receptor cells detect nutrients and toxins in the oral cavity and transmit the sensory information to gustatory nerve endings in the buds. Supporting cells may play a role in the clearance of excess neurotransmitters after their release from taste receptor cells. Basal cells are precursor cells that differentiate into mature taste cells. Similar to other epithelial cells, taste cells turn over continuously, with an average life span of about 8-12 days. To maintain structural homeostasis in taste buds, new cells are generated to replace dying cells. Several recent studies using genetic lineage tracing methods have identified populations of progenitor/stem cells for taste buds, although contributions of these progenitor/stem cell populations to taste bud homeostasis have yet to be fully determined. Some regulatory factors of taste cell differentiation and degeneration have been identified, but our understanding of these aspects of taste bud homoeostasis remains limited. Many patients with various diseases develop taste disorders, including taste loss and taste distortion. Decline in taste function also occurs during aging. Recent studies suggest that disruption or alteration of taste bud homeostasis may contribute to taste dysfunction associated with disease and aging.

Developing partnerships for implementing continental-scale citizen science programs at the local-level

NASA Astrophysics Data System (ADS)

Newman, S. J.; Henderson, S.; Ward, D.

2012-12-01

Project BudBurst is a citizen science project focused on monitoring plant phenology that resides at the National Ecological Observatory Network (NEON, Inc). A central question for Project BudBurst and other national outreach programs is: what are the most effective means of engaging and connecting with diverse communities throughout the country? How can continental scale programs like NEON's Project BudBurst engage audiences in such a way as to be relevant at both the local and continental scales? Staff with Project BudBurst pursued partnerships with several continental scale organizations: the National Wildlife Refuge System, the National Park Service, and botanic gardens to address these questions. The distributed nature of wildlife refuges, national parks, and botanic gardens around the country provided the opportunity to connect with participants locally while working with leadership at multiple scales. Project BudBurst staff talked with hundreds of staff and volunteers prior to setting a goal of obtaining and developing resources for several Refuge Partners, a pilot National Park partner, and an existing botanic garden partner during 2011. We were especially interested in learning best practices for future partnerships. The partnership efforts resulted in resource development for 12 Refuge partners, a pilot National Park partner, and 2 botanic garden partners. Early on, the importance of working with national level leaders to develop ownership of the partner program and input about resource needs became apparent. Once a framework for the partnership program was laid out, it became critical to work closely with staff and volunteers on the ground to ensure needs were met. In 2012 we began to develop an online assessment to allow our current and potential partners to provide feedback about whether or not the partnership program was meeting their needs and how the program could be improved. As the year progressed, the timeline for resource development became more of a suggestion than a set schedule. Maintaining flexibility was critical to the success of the partnerships. Unanticipated fieldwork, new priorities within organizations, and differing levels of involvement from partner staff, advisory boards, or Friends groups, led to varying resource development timelines. The distributed nature of and the willingness of partner staff and volunteers to implement Project BudBurst at their facilities have broadened the participation of the public in this program more than could have been accomplished alone. The new partners benefit from the free and customized education and outreach materials provided by Project BudBurst, while Project BudBurst benefits from the local knowledge and contacts with the public from the partner organizations.

Role of TCP Gene BRANCHED1 in the Control of Shoot Branching in Arabidopsis.

PubMed

Poza-Carrión, César; Aguilar-Martínez, José Antonio; Cubas, Pilar

2007-11-01

Branching patterns are major determinants of plant architecture. They depend both on leaf phillotaxy (branch primordia are formed in the axils of leaves) and on the decision of buds to grow out to give a branch or to remain dormant. In Arabidopsis, several genes involved in the long-distance signalling of the control of branch outgrowth have been identified. However, the genes acting inside the buds to cause growth arrest remained unknown until now. In the February issue of Plant Cell we have described the function of BRANCHED1 (BRC1), an Arabidopsis gene coding for a plant-specific transcription factor of the TCP family that is expressed in the buds and prevents their development. Loss of BRC1 function leads to accelerated AM initiation, precocious progression of bud development and excess of shoot branching. BRC1 transcription is affected by endogenous and environmental signals controlling branching and we have shown that BRC1 function mediates the response to these stimuli. Therefore we have proposed that BRC1 function represents the point at which signals controlling branching are integrated within axillary buds.

Functional cell types in taste buds have distinct longevities.

PubMed

Perea-Martinez, Isabel; Nagai, Takatoshi; Chaudhari, Nirupa

2013-01-01

Taste buds are clusters of polarized sensory cells embedded in stratified oral epithelium. In adult mammals, taste buds turn over continuously and are replenished through the birth of new cells in the basal layer of the surrounding non-sensory epithelium. The half-life of cells in mammalian taste buds has been estimated as 8-12 days on average. Yet, earlier studies did not address whether the now well-defined functional taste bud cell types all exhibit the same lifetime. We employed a recently developed thymidine analog, 5-ethynil-2'-deoxyuridine (EdU) to re-evaluate the incorporation of newly born cells into circumvallate taste buds of adult mice. By combining EdU-labeling with immunostaining for selected markers, we tracked the differentiation and lifespan of the constituent cell types of taste buds. EdU was primarily incorporated into basal extragemmal cells, the principal source for replenishing taste bud cells. Undifferentiated EdU-labeled cells began migrating into circumvallate taste buds within 1 day of their birth. Type II (Receptor) taste cells began to differentiate from EdU-labeled precursors beginning 2 days after birth and then were eliminated with a half-life of 8 days. Type III (Presynaptic) taste cells began differentiating after a delay of 3 days after EdU-labeling, and they survived much longer, with a half-life of 22 days. We also scored taste bud cells that belong to neither Type II nor Type III, a heterogeneous group that includes mostly Type I cells, and also undifferentiated or immature cells. A non-linear decay fit described these cells as two sub-populations with half-lives of 8 and 24 days respectively. Our data suggest that many post-mitotic cells may remain quiescent within taste buds before differentiating into mature taste cells. A small number of slow-cycling cells may also exist within the perimeter of the taste bud. Based on their incidence, we hypothesize that these may be progenitors for Type III cells.

Functional Cell Types in Taste Buds Have Distinct Longevities

PubMed Central

Perea-Martinez, Isabel; Nagai, Takatoshi; Chaudhari, Nirupa

2013-01-01

Taste buds are clusters of polarized sensory cells embedded in stratified oral epithelium. In adult mammals, taste buds turn over continuously and are replenished through the birth of new cells in the basal layer of the surrounding non-sensory epithelium. The half-life of cells in mammalian taste buds has been estimated as 8–12 days on average. Yet, earlier studies did not address whether the now well-defined functional taste bud cell types all exhibit the same lifetime. We employed a recently developed thymidine analog, 5-ethynil-2′-deoxyuridine (EdU) to re-evaluate the incorporation of newly born cells into circumvallate taste buds of adult mice. By combining EdU-labeling with immunostaining for selected markers, we tracked the differentiation and lifespan of the constituent cell types of taste buds. EdU was primarily incorporated into basal extragemmal cells, the principal source for replenishing taste bud cells. Undifferentiated EdU-labeled cells began migrating into circumvallate taste buds within 1 day of their birth. Type II (Receptor) taste cells began to differentiate from EdU-labeled precursors beginning 2 days after birth and then were eliminated with a half-life of 8 days. Type III (Presynaptic) taste cells began differentiating after a delay of 3 days after EdU-labeling, and they survived much longer, with a half-life of 22 days. We also scored taste bud cells that belong to neither Type II nor Type III, a heterogeneous group that includes mostly Type I cells, and also undifferentiated or immature cells. A non-linear decay fit described these cells as two sub-populations with half-lives of 8 and 24 days respectively. Our data suggest that many post-mitotic cells may remain quiescent within taste buds before differentiating into mature taste cells. A small number of slow-cycling cells may also exist within the perimeter of the taste bud. Based on their incidence, we hypothesize that these may be progenitors for Type III cells. PMID:23320081

Dehydration and osmotic adjustment in apple stem tissue during winter as it relates to the frost resistance of buds.

PubMed

Pramsohler, Manuel; Neuner, Gilbert

2013-08-01

In deciduous trees, measurement of stem water potential can be difficult during the leafless period in winter. By using thermocouple psychrometry, osmotic water potentials (Ψo; actual Ψo: Ψo(act); Ψo at full saturation: Ψo(sat)) of expressed sap of bark and bud tissue were measured in order to test if the severity of winter desiccation in apple stems could be sufficiently assessed with Ψo. Water potentials were related to frost resistance and freezing behaviour of buds. The determination of Ψo reliably allowed winter desiccation and osmotic adjustments in apple stem tissue to be assessed. In winter in bark tissue, a pronounced decrease in Ψo(act) and Ψo(sat) was found. Decreased Ψo(sat) indicates active osmotic adjustment in the bark as observed earlier in the leaves of evergreen woody plants. In terminal bud meristems, no significant osmotic adjustments occurred and dehydration during winter was much less. Osmotic water potentials, Ψo(act) and Ψo(sat), of bud tissue were always less negative than in the bark. To prevent water movement and dehydration of the bud tissue via this osmotic gradient, it must be compensated for either by a sufficiently high turgor pressure (Ψp) in bark tissue or by the isolation of the bud tissue from the bark during midwinter. During freezing of apple buds, freeze dehydration and extra-organ freezing could be demonstrated by significantly reduced Ψo(act) values of bud meristems that had been excised in the frozen state. Infrared video thermography was used to monitor freezing patterns in apple twigs. During extracellular freezing of intact and longitudinally dissected stems, infrared differential thermal analysis (IDTA) images showed that the bud meristem remains ice free. Even if cooled to temperatures below the frost-killing temperature, no freezing event could be detected in bud meristems during winter. In contrast, after bud break, terminal buds showed a second freezing at the frost-killing temperature that indicates deep supercooling. Our results demonstrate the applicability of thermocouple psychrometry for the assessment of winter desiccation in stem tissues of deciduous trees and corroborate the finding that dormant apple buds survive by extra-organ freezing and do not deep supercool. In addition, they indicate that significant changes of the frost-survival mechanism can occur during the apple bud development in spring.

Tissue culture of three species of Laurencia complex

NASA Astrophysics Data System (ADS)

Shen, Songdong; Wu, Xunjian; Yan, Binlun; He, Lihong

2010-05-01

To establish a micropropagation system of three Laurencia complex species ( Laurencia okamurai, Laurencia tristicha, and Chondrophycus undulatus) by tissue culture techniques, we studied the regeneration characteristics and optimal culture conditions of axenic algal fragments cultured on solid medium and in liquid medium. Regeneration structures were observed and counted regularly under a reverse microscope to investigate the regeneration process, polarity and optimal illumination, and temperature and salinity levels. The results show that in most cultures of the three species, we obtained bud regeneration on solidified medium with 0.5% agar and in liquid medium. Rhizoid-like regeneration was filamentous and developed from the lower cut surface of fragments in L. okamurai, but was discoid and developed from the apical back side of bud regeneration in L. tristicha and C. undulatus. Regeneration polarity was localized to the apical part of algal fronds in all three species, and on fragments cut from the basal part of algae buds could develop from both the upper and the lower cut surfaces. Buds could develop from both the medullary and the cortical portions in L. okamurai and C. undulatus, while in L. tristicha, buds only emerged from the cortex. The optimal culture conditions for L. okamurai were 4 500 lx, 20°C and 35 (salinity); for C. undulatus, 4 500 lx, 20°C and 30; and for L. tristicha, 4 500 lx, 25°C and 30.

Gustatory papillae and taste bud development and maintenance in the absence of TrkB ligands BDNF and NT-4.

PubMed

Ito, Akira; Nosrat, Christopher A

2009-09-01

Taste buds and the peripheral nerves innervating them are two important components of the peripheral gustatory system. They require appropriate connections for the taste system to function. Neurotrophic factors play crucial roles in the innervation of peripheral sensory organs and tissues. Both brain-derived neurotrophic factor (BDNF) null-mutated and neurotrophin-4 (NT-4) null-mutated mice exhibit peripheral gustatory deficits. BDNF and NT-4 bind to a common high affinity tyrosine kinase receptor, TrkB (NTRK-2), and a common p75 neurotrophin receptor (NGFR). We are currently using a transgenic mouse model to study peripheral taste system development and innervation in the absence of both TrkB ligands. We show that taste cell progenitors express taste cell markers during early stages of taste bud development in both BDNF(-/-)xNT-4(-/-) and wild-type mice. At early embryonic stages, taste bud progenitors express Troma-1, Shh, and Sox2 in all mice. At later stages, lack of innervation becomes a prominent feature in BDNF(-/-)xNT-4(-/-) mice leading to a decreasing number of fungiform papillae and morphologically degenerating taste cells. A total loss of vallate taste cells also occurs in postnatal transgenic mice. Our data indicate an initial independence but a later permissive and essential role for innervation in taste bud development and maintenance.

Synchronisms between bud and cambium phenology in black spruce: early-flushing provenances exhibit early xylem formation.

PubMed

Perrin, Magali; Rossi, Sergio; Isabel, Nathalie

2017-05-01

Bud and cambial phenology represent the adaptation of species to the local environment that allows the growing season to be maximized while minimizing the risk of frost for the developing tissues. The temporal relationship between the apical and radial meristems can help in the understanding of tree growth as a whole process. The aim of this study was to compare cambial phenology in black spruce (Picea mariana (Mill.) B.S.P.) provenances classified as early and late bud flushing. The different phases of cambial phenology were assessed on wood microcores sampled weekly from April to October in 2014 and 2015 from 61 trees growing in a provenance trial in Quebec, Canada. Trees showing an early bud flush also exhibited early reactivation of xylem differentiation, although an average difference of 12 days for buds corresponded to small although significant differences of 4 days for xylem. Provenances with early bud flush had an early bud set and completed xylem formation earlier than late bud flush provenances. No significant difference in the period of xylem formation and total growth was observed between the flushing classes. Our results demonstrate that the ecotype differentiation of black spruce provenances represented by the phenological adaptation of buds to the local climate corresponds to specific growth dynamics of the xylem. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Annual cycle of shoot development in sugar maple

Treesearch

Robert A. Gregory

1980-01-01

Cytohistology and the development and morphogenesis of sugar maple (Acer saccharum Marsh.) shoots were studied. Three types were recognized: short shoots, long shoots entirely preformed in the bud (Epf long), and long shoots partially preformed in the bud (heterophyllous). The three shoot types varied not only in the size and number of internodes...

Flufenoxuron, an insect growth regulator, promotes peroral infection by nucleopolyhedrovirus (BmNPV) budded particles in the silkworm, Bombyx mori L.

PubMed

Arakawa, Toru; Furuta, Yoji; Miyazawa, Mitsuhiro; Kato, Masao

2002-02-01

A novel method was developed to infect perorally the silkworm Bombyx mori L. with budded particles of nucleopolyhedrovirus (BmNPV) using flufenoxuron, an insect growth regulator. NPV vectors are used to obtain proteins that occur naturally in minute amounts. NPV vectors are constructed conventionally by replacing the polyhedrin gene with the foreign gene of interest. These vectors thus do not produce polyhedra. The budded virus particle suspension of these vectors is produced in a cell culture and used as the stock inoculum. Budded NPV particles do not infect their host perorally. The inoculum is injected manually into the individual host using a syringe. It was found that B. mori L. fed on the insect growth regulator flufenoxuron were sensitive to BmNPV budded particles given perorally. Over 90% of B. mori L. ingesting BmNPV budded particles (1.3 x 10(6) TCID(50) units per larva) after consuming an artificial diet for 24 h, containing 0.1% (w/w) flufenoxuron died of the viral infection. The peroral inoculation of BmNPV budded particles by flufenoxuron may thus lead to industrial pharmaceutical production using a baculovirus vector for large numbers of insect hosts.

Beta-catenin (CTNNB1) induces Bmp expression in urogenital sinus epithelium and participates in prostatic bud initiation and patterning

PubMed Central

Mehta, Vatsal; Schmitz, Christopher T.; Keil, Kimberly P.; Joshi, Pinak S.; Abler, Lisa L.; Lin, Tien-Min; Taketo, Makoto M.; Sun, Xin; Vezina, Chad M.

2013-01-01

Fetal prostate development is initiated by androgens and patterned by androgen dependent and independent signals. How these signals integrate to control epithelial cell differentiation and prostatic bud patterning is not fully understood. To test the role of beta-catenin (Ctnnb1) in this process, we used a genetic approach to conditionally delete or stabilize Ctnnb1 in urogenital sinus (UGS) epithelium from which the prostate derives. Two opposing mechanisms of action were revealed. By deleting Ctnnb1, we found it is required for separation of UGS from cloaca, emergence or maintenance of differentiated UGS basal epithelium and formation of prostatic buds. By genetically inducing a patchy subset of UGS epithelial cells to express excess CTNNB1, we found its excess abundance increases Bmp expression and leads to a global impairment of prostatic bud formation. Addition of NOGGIN partially restores prostatic budding in UGS explants with excess Ctnnb1. These results indicate a requirement for Ctnnb1 in UGS basal epithelial cell differentiation, prostatic bud initiation and bud spacing and suggest some of these actions are mediated in part through activation of BMP signaling. PMID:23396188

The protein phosphatase inhibitor cantharidin induces head and foot formation in buds of Cassiopea andromeda (Rhizostomae, Scyphozoa).

PubMed

Kehls, N E; Herrmann, K; Berking, S

1999-01-01

The polyps of Cassiopea andromeda produce spindle shaped, freely swimming buds which do not develop a head (a mouth opening surrounded by tentacles) and a foot (a sticky plate at the opposite end) until settlement to a suited substrate. The buds, therewith, look very similar to the planula larvae produced in sexual reproduction. With respect to both, buds and planulae, several peptides and the phorbolester TPA have been found to induce the transformation into a polyp. Here it is shown that cantharidin, a serine/threonine protein phosphatase inhibitor, induces head and foot formation in buds very efficiently in a 30 min treatment, the shortest yet known efficient treatment. Some resultant polyps show malformations which indicate that a bud is ordinary polyp tissue in which preparatory steps of head and foot formation mutually block each other from proceeding. Various compounds related to the transfer of methyl groups have been shown to affect head and foot formation in larvae of the hydrozoon Hydractinia echinata. These compounds including methionine, homocysteine, trigonelline, nicotinic acid and cycloleucine are shown to also interfere with the initiation of the processes which finally lead to head and foot formation in buds of Cassiopea andromeda.

Developing and regenerating a sense of taste

PubMed Central

Barlow, Linda A.; Klein, Ophir D.

2015-01-01

Taste is one of the fundamental senses, and it is essential for our ability to ingest nutritious substances and to detect and avoid potentially toxic ones. Taste buds, which are clusters of neuroepithelial receptor cells, are housed in highly organized structures called taste papillae in the oral cavity. Whereas the overall structure of the taste periphery is conserved in almost all vertebrates examined to date, the anatomical, histological, and cell biological, as well as potentially the molecular details of taste buds in the oral cavity are diverse across species and even among individuals. In mammals, several types of gustatory papillae reside on the tongue in highly ordered arrangements, and the patterning and distribution of the mature papillae depends on coordinated molecular events in embryogenesis. In this review, we highlight new findings in the field of taste development, including how taste buds are patterned and how taste cell fate is regulated. We discuss whether a specialized taste bud stem cell population exists and how extrinsic signals can define which cell lineages are generated. We also address the question of whether molecular regulation of taste cell renewal is analogous to that of taste bud development. Finally, we conclude with suggestions for future directions, including the potential influence of the maternal diet and maternal health on the sense of taste in utero. PMID:25662267

De novo Transcriptome Analysis of Miscanthus lutarioriparius Identifies Candidate Genes in Rhizome Development

PubMed Central

Hu, Ruibo; Yu, Changjiang; Wang, Xiaoyu; Jia, Chunlin; Pei, Shengqiang; He, Kang; He, Guo; Kong, Yingzhen; Zhou, Gongke

2017-01-01

HIGHLIGHT De novo transcriptome profiling of five tissues reveals candidate genes putatively involved in rhizome development in M. lutarioriparius. Miscanthus lutarioriparius is a promising lignocellulosic feedstock for second-generation bioethanol production. However, the genomic resource for this species is relatively limited thus hampers our understanding of the molecular mechanisms underlying many important biological processes. In this study, we performed the first de novo transcriptome analysis of five tissues (leaf, stem, root, lateral bud and rhizome bud) of M. lutarioriparius with an emphasis to identify putative genes involved in rhizome development. Approximately 66 gigabase (GB) paired-end clean reads were obtained and assembled into 169,064 unigenes with an average length of 759 bp. Among these unigenes, 103,899 (61.5%) were annotated in seven public protein databases. Differential gene expression profiling analysis revealed that 4,609, 3,188, 1,679, 1,218, and 1,077 genes were predominantly expressed in root, leaf, stem, lateral bud, and rhizome bud, respectively. Their expression patterns were further classified into 12 distinct clusters. Pathway enrichment analysis revealed that genes predominantly expressed in rhizome bud were mainly involved in primary metabolism and hormone signaling and transduction pathways. Noteworthy, 19 transcription factors (TFs) and 16 hormone signaling pathway-related genes were identified to be predominantly expressed in rhizome bud compared with the other tissues, suggesting putative roles in rhizome formation and development. In addition, a predictive regulatory network was constructed between four TFs and six auxin and abscisic acid (ABA) -related genes. Furthermore, the expression of 24 rhizome-specific genes was further validated by quantitative real-time RT-PCR (qRT-PCR) analysis. Taken together, this study provide a global portrait of gene expression across five different tissues and reveal preliminary insights into rhizome growth and development. The data presented will contribute to our understanding of the molecular mechanisms underlying rhizome development in M. lutarioriparius and remarkably enrich the genomic resources of Miscanthus. PMID:28446913

Xylem Development in Prunus Flower Buds and the Relationship to Deep Supercooling

PubMed Central

Ashworth, Edward N.

1984-01-01

Xylem development in eight Prunus species was examined and the relationship to deep supercooling assessed. Dormant buds of six species, P. armeniaca, P. avium, P. cerasus, P. persica, P. salicina, and P. sargentii deep supercooled. Xylem vessel elements were not observed within the dormant floral primordia of these species. Instead, discrete bundles containing procambial cells were observed. Vascular differentiation resumed and xylem continuity was established during the time that the capacity to deep supercool was lost. In P. serotina and P. virginiana, two species which do not supercool, xylem vessels ran the length of the inflorescence and presumably provided a conduit for the spread of ice into the bud. The results support the hypothesis that the lack of xylem continuity is an important feature of buds which deep supercool. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:16663523

Yield of illicit indoor cannabis cultivation in the Netherlands.

PubMed

Toonen, Marcel; Ribot, Simon; Thissen, Jac

2006-09-01

To obtain a reliable estimation on the yield of illicit indoor cannabis cultivation in The Netherlands, cannabis plants confiscated by the police were used to determine the yield of dried female flower buds. The developmental stage of flower buds of the seized plants was described on a scale from 1 to 10 where the value of 10 indicates a fully developed flower bud ready for harvesting. Using eight additional characteristics describing the grow room and cultivation parameters, regression analysis with subset selection was carried out to develop two models for the yield of indoor cannabis cultivation. The median Dutch illicit grow room consists of 259 cannabis plants, has a plant density of 15 plants/m(2), and 510 W of growth lamps per m(2). For the median Dutch grow room, the predicted yield of female flower buds at the harvestable developmental stage (stage 10) was 33.7 g/plant or 505 g/m(2).

Zone of Polarizing Activity Regulatory Sequence Mutations/Duplications with Preaxial Polydactyly and Longitudinal Preaxial Ray Deficiency in the Phenotype: A Review of Human Cases, Animal Models, and Insights Regarding the Pathogenesis

PubMed Central

2018-01-01

Clinicians and scientists interested in developmental biology have viewed preaxial polydactyly (PPD) and longitudinal preaxial ray deficiency (LPAD) as two different entities. Point mutations and duplications in the zone of polarizing activity regulatory sequence (ZRS) are associated with anterior ectopic expression of Sonic Hedgehog (SHH) in the limb bud and usually result in a PPD phenotype. However, some of these mutations/duplications also have LPAD in the phenotype. This unusual PPD-LPAD association in ZRS mutations/duplications has not been specifically reviewed in the literature. The author reviews this unusual entity and gives insights regarding its pathogenesis. PMID:29651423

Inflammation activates the interferon signaling pathways in taste bud cells.

PubMed

Wang, Hong; Zhou, Minliang; Brand, Joseph; Huang, Liquan

2007-10-03

Patients with viral and bacterial infections or other inflammatory illnesses often experience taste dysfunctions. The agents responsible for these taste disorders are thought to be related to infection-induced inflammation, but the mechanisms are not known. As a first step in characterizing the possible role of inflammation in taste disorders, we report here evidence for the presence of interferon (IFN)-mediated signaling pathways in taste bud cells. IFN receptors, particularly the IFN-gamma receptor IFNGR1, are coexpressed with the taste cell-type markers neuronal cell adhesion molecule and alpha-gustducin, suggesting that both the taste receptor cells and synapse-forming cells in the taste bud can be stimulated by IFN. Incubation of taste bud-containing lingual epithelia with recombinant IFN-alpha and IFN-gamma triggered the IFN-mediated signaling cascades, resulting in the phosphorylation of the downstream STAT1 (signal transducer and activator of transcription protein 1) transcription factor. Intraperitoneal injection of lipopolysaccharide or polyinosinic:polycytidylic acid into mice, mimicking bacterial and viral infections, respectively, altered gene expression patterns in taste bud cells. Furthermore, the systemic administration of either IFN-alpha or IFN-gamma significantly increased the number of taste bud cells undergoing programmed cell death. These findings suggest that bacterial and viral infection-induced IFNs can act directly on taste bud cells, affecting their cellular function in taste transduction, and that IFN-induced apoptosis in taste buds may cause abnormal cell turnover and skew the representation of different taste bud cell types, leading to the development of taste disorders. To our knowledge, this is the first study providing direct evidence that inflammation can affect taste buds through cytokine signaling pathways.

A Nonsynonymous Mutation in the Transcriptional Regulator lbh Is Associated with Cichlid Craniofacial Adaptation and Neural Crest Cell Development

PubMed Central

Powder, Kara E.; Cousin, Hélène; McLinden, Gretchen P.; Craig Albertson, R.

2014-01-01

Since the time of Darwin, biologists have sought to understand the origins and maintenance of life’s diversity of form. However, the nature of the exact DNA mutations and molecular mechanisms that result in morphological differences between species remains unclear. Here, we characterize a nonsynonymous mutation in a transcriptional coactivator, limb bud and heart homolog (lbh), which is associated with adaptive variation in the lower jaw of cichlid fishes. Using both zebrafish and Xenopus, we demonstrate that lbh mediates migration of cranial neural crest cells, the cellular source of the craniofacial skeleton. A single amino acid change that is alternatively fixed in cichlids with differing facial morphologies results in discrete shifts in migration patterns of this multipotent cell type that are consistent with both embryological and adult craniofacial phenotypes. Among animals, this polymorphism in lbh represents a rare example of a coding change that is associated with continuous morphological variation. This work offers novel insights into the development and evolution of the craniofacial skeleton, underscores the evolutionary potential of neural crest cells, and extends our understanding of the genetic nature of mutations that underlie divergence in complex phenotypes. PMID:25234704

Expression of GAD67 and Dlx5 in the taste buds of mice genetically lacking Mash1.

PubMed

Kito-Shingaki, Ayae; Seta, Yuji; Toyono, Takashi; Kataoka, Shinji; Kakinoki, Yasuaki; Yanagawa, Yuchio; Toyoshima, Kuniaki

2014-06-01

It has been reported that a subset of type III taste cells express glutamate decarboxylase (GAD)67, which is a molecule that synthesizes gamma-aminobutyric acid (GABA), and that Mash1 could be a potential regulator of the development of GABAnergic neurons via Dlx transcription factors in the central nervous system. In this study, we investigated the expression of GAD67 and Dlx in the embryonic taste buds of the soft palate and circumvallate papilla using Mash1 knockout (KO)/GAD67-GFP knock-in mice. In the wild-type animal, a subset of type III taste cells contained GAD67 in the taste buds of the soft palate and the developing circumvallate papilla, whereas GAD67-expressing taste bud cells were missing from Mash1 KO mice. A subset of type III cells expressed mRNA for Dlx5 in the wild-type animals, whereas Dlx5-expressing cells were not evident in the apical part of the circumvallate papilla and taste buds in the soft palate of Mash1 KO mice. Our results suggest that Mash1 is required for the expression of GAD67 and Dlx5 in taste bud cells. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The anillin-related region of Bud4 is the major functional determinant for Bud4's function in septin organization during bud growth and axial bud site selection in budding yeast.

PubMed

Wu, Huan; Guo, Jia; Zhou, Ya-Ting; Gao, Xiang-Dong

2015-03-01

The anillin-related protein Bud4 of Saccharomyces cerevisiae is required for axial bud site selection by linking the axial landmark to the septins, which localize at the mother bud neck. Recent studies indicate that Bud4 plays a role in septin organization during cytokinesis. Here we show that Bud4 is also involved in septin organization during bud growth prior to cytokinesis, as bud4Δ shs1Δ cells displayed an elongated bud morphology and defective septin organization at 18°C. Bud4 overexpression also affected septin organization during bud growth in shs1Δ cells at 30°C. Bud4 was previously thought to associate with the septins via its central region, while the C-terminal anillin-related region was not involved in septin association. Surprisingly, we found that the central region of Bud4 alone targets to the bud neck throughout the cell cycle, unlike full-length Bud4, which localizes to the bud neck only during G2/M phase. We identified the anillin-related region to be a second targeting domain that cooperates with the central region for proper septin association. In addition, the anillin-related region could largely mediate Bud4's function in septin organization during bud growth and bud site selection. We show that this region interacts with the C terminus of Bud3 and the two segments depend on each other for association with the septins. Moreover, like the bud4Δ mutant, the bud3Δ mutant genetically interacts with shs1Δ and cdc12-6 mutants in septin organization, suggesting that Bud4 and Bud3 may cooperate in septin organization during bud growth. These observations provide new insights into the interaction of Bud4 with the septins and Bud3. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Alternate Bearing in Citrus: Changes in the Expression of Flowering Control Genes and in Global Gene Expression in ON- versus OFF-Crop Trees

PubMed Central

Shalom, Liron; Samuels, Sivan; Zur, Naftali; Shlizerman, Lyudmila; Zemach, Hanita; Weissberg, Mira; Ophir, Ron; Blumwald, Eduardo; Sadka, Avi

2012-01-01

Alternate bearing (AB) is the process in fruit trees by which cycles of heavy yield (ON crop) one year are followed by a light yield (OFF crop) the next. Heavy yield usually reduces flowering intensity the following year. Despite its agricultural importance, how the developing crop influences the following year's return bloom and yield is not fully understood. It might be assumed that an ‘AB signal’ is generated in the fruit, or in another organ that senses fruit presence, and moves into the bud to determine its fate—flowering or vegetative growth. The bud then responds to fruit presence by altering regulatory and metabolic pathways. Determining these pathways, and when they are altered, might indicate the nature of this putative AB signal. We studied bud morphology, the expression of flowering control genes, and global gene expression in ON- and OFF-crop buds. In May, shortly after flowering and fruit set, OFF-crop buds were already significantly longer than ON-crop buds. The number of differentially expressed genes was higher in May than at the other tested time points. Processes differentially expressed between ON- and OFF-crop trees included key metabolic and regulatory pathways, such as photosynthesis and secondary metabolism. The expression of genes of trehalose metabolism and flavonoid metabolism was validated by nCounter technology, and the latter was confirmed by metabolomic analysis. Among genes induced in OFF-crop trees was one homologous to SQUAMOSA PROMOTER BINDING-LIKE (SPL), which controls juvenile-to-adult and annual phase transitions, regulated by miR156. The expression pattern of SPL-like, miR156 and other flowering control genes suggested that fruit load affects bud fate, and therefore development and metabolism, a relatively long time before the flowering induction period. Results shed light on some of the metabolic and regulatory processes that are altered in ON and OFF buds. PMID:23071667

Shoot bending promotes flower bud formation by miRNA-mediated regulation in apple (Malus domestica Borkh.).

PubMed

Xing, Libo; Zhang, Dong; Zhao, Caiping; Li, Youmei; Ma, Juanjuan; An, Na; Han, Mingyu

2016-02-01

Flower induction in apple (Malus domestica Borkh.) trees plays an important life cycle role, but young trees produce fewer and inferior quality flower buds. Therefore, shoot bending has become an important cultural practice, significantly promoting the capacity to develop more flower buds during the growing seasons. Additionally, microRNAs (miRNAs) play essential roles in plant growth, flower induction and stress responses. In this study, we identified miRNAs potentially involved in the regulation of bud growth, and flower induction and development, as well as in the response to shoot bending. Of the 195 miRNAs identified, 137 were novel miRNAs. The miRNA expression profiles revealed that the expression levels of 68 and 27 known miRNAs were down-regulated and up-regulated, respectively, in response to shoot bending, and that the 31 differentially expressed novel miRNAs between them formed five major clusters. Additionally, a complex regulatory network associated with auxin, cytokinin, abscisic acid (ABA) and gibberellic acid (GA) plays important roles in cell division, bud growth and flower induction, in which related miRNAs and targets mediated regulation. Among them, miR396, 160, 393, and their targets associated with AUX, miR159, 319, 164, and their targets associated with ABA and GA, and flowering-related miRNAs and genes, regulate bud growth and flower bud formation in response to shoot bending. Meanwhile, the flowering genes had significantly higher expression levels during shoot bending, suggesting that they are involved in this regulatory process. This study provides a framework for the future analysis of miRNAs associated with multiple hormones and their roles in the regulation of bud growth, and flower induction and formation in response to shoot bending in apple trees. © 2015 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Alternate bearing in citrus: changes in the expression of flowering control genes and in global gene expression in ON- versus OFF-crop trees.

PubMed

Shalom, Liron; Samuels, Sivan; Zur, Naftali; Shlizerman, Lyudmila; Zemach, Hanita; Weissberg, Mira; Ophir, Ron; Blumwald, Eduardo; Sadka, Avi

2012-01-01

Alternate bearing (AB) is the process in fruit trees by which cycles of heavy yield (ON crop) one year are followed by a light yield (OFF crop) the next. Heavy yield usually reduces flowering intensity the following year. Despite its agricultural importance, how the developing crop influences the following year's return bloom and yield is not fully understood. It might be assumed that an 'AB signal' is generated in the fruit, or in another organ that senses fruit presence, and moves into the bud to determine its fate-flowering or vegetative growth. The bud then responds to fruit presence by altering regulatory and metabolic pathways. Determining these pathways, and when they are altered, might indicate the nature of this putative AB signal. We studied bud morphology, the expression of flowering control genes, and global gene expression in ON- and OFF-crop buds. In May, shortly after flowering and fruit set, OFF-crop buds were already significantly longer than ON-crop buds. The number of differentially expressed genes was higher in May than at the other tested time points. Processes differentially expressed between ON- and OFF-crop trees included key metabolic and regulatory pathways, such as photosynthesis and secondary metabolism. The expression of genes of trehalose metabolism and flavonoid metabolism was validated by nCounter technology, and the latter was confirmed by metabolomic analysis. Among genes induced in OFF-crop trees was one homologous to SQUAMOSA PROMOTER BINDING-LIKE (SPL), which controls juvenile-to-adult and annual phase transitions, regulated by miR156. The expression pattern of SPL-like, miR156 and other flowering control genes suggested that fruit load affects bud fate, and therefore development and metabolism, a relatively long time before the flowering induction period. Results shed light on some of the metabolic and regulatory processes that are altered in ON and OFF buds.

Use of NASA Bioreactor in Engineering Tissue for Bone Repair

NASA Technical Reports Server (NTRS)

Duke, Pauline

1998-01-01

This study was proposed in search for a new alternative for bone replacement or repair. Because the systems commonly used in repair of bony defects form bone by going through a cartilaginous phase, implantation of a piece of cartilage could enhance the healing process by having a more advanced starting point. However, cartilage has seldom been used to replace bone due, in part, to the limitations in conventional culture systems that did not allow production of enough tissue for implants. The NASA-developed bioreactors known as STLV (Slow Turning Lateral Vessel) provide homogeneous distribution of cells, nutrients, and waste products, with less damaging turbulence and shear forces than conventional systems. Cultures under these conditions have higher growth rates, viability, and longevity, allowing larger "tissue-like" aggregates to form, thus opening the possibilities of producing enough tissue for implantation, along with the inherent advantages of in vitro manipulations. To assure large numbers of cells and to eliminate the use of timed embryos, we proposed to use an immortalized mouse limb bud cell line as the source of cells.

In vitro food production for isolated closed environments: formation of ripe tomato fruits from excised flower buds.

PubMed

Applewhite, P B; K-Sawhney, R; Galston, A W

1997-01-01

Excised preanthesis flower buds of young Pixie Hybrid tomato plants develop into red ripe fruits in aseptic culture on a modified Murashige-Skoog medium with 3% sucrose at pH 5.8. The addition of certain synthetic auxins (IAA, NAA, IBA), auxin precursors (ISA), or cytokinins (KIN, IPA, ZEA, BAP) to the medium improved the percentage of buds developing into fruits, the weight of the ripe fruits, or both. The best results were obtained by an auxin-cytokinin combination of 10 microM IBA with 1 microM BAP. Storage of the excised buds at low temperature (6 degrees C) for up to 4 weeks before transfer to 27 degrees C caused only minimal deterioration in size and number of the fruit crop. Extension of low-temperature storage to 8 weeks produced smaller fruits that took longer to develop. This system could produce fresh, ripe small tomatoes on a sustained basis for up to 2 months for an isolated environment such as a space vehicle or submarine.

Utility of HoxB2 enhancer-mediated Cre activity for functional studies in the developing inner ear.

PubMed

Szeto, Irene Y Y; Leung, Keith K H; Sham, Mai Har; Cheah, Kathryn S E

2009-06-01

The rhombomere 4(r4)-restricted expression of the mouse Hoxb2 gene is regulated by a 1.4-kb enhancer-containing fragment. Here, we showthat transgenic mouse lines expressing cre driven by this fragment (B2-r4-Cre), activated the R26R Cre reporter in rhombomere 4 and the second branchial arch, the epithelium of the first branchial arch, apical ectodermal ridge of the limb buds and the tail region. Of particular interest is Cre activity in the developing inner ear. Cre activity was found in the preotic field and otic placode at E8.5 and otocyst at E9.5-E12.5, in the cochleovestibular and facio-acoustic ganglia at E10.5 and the vestibular and spiral ganglia and all the otic epithelia derived from the otocyst at E15.5 and P0. Our data suggest that the B2-r4-Cre transgenic mice provide an important tool for conditional gene manipulation and lineage tracing in the inner ear. In combination with other transgenic lines expressing cre exclusively in the otic vesicle, the relative contributions of the hindbrain, periotic mesenchyme and otic epithelium in otic development can be dissected. Copyright 2009 Wiley-Liss, Inc.

Developing and regenerating a sense of taste.

PubMed

Barlow, Linda A; Klein, Ophir D

2015-01-01

Taste is one of the fundamental senses, and it is essential for our ability to ingest nutritious substances and to detect and avoid potentially toxic ones. Taste buds, which are clusters of neuroepithelial receptor cells, are housed in highly organized structures called taste papillae in the oral cavity. Whereas the overall structure of the taste periphery is conserved in almost all vertebrates examined to date, the anatomical, histological, and cell biological, as well as potentially the molecular details of taste buds in the oral cavity are diverse across species and even among individuals. In mammals, several types of gustatory papillae reside on the tongue in highly ordered arrangements, and the patterning and distribution of the mature papillae depend on coordinated molecular events in embryogenesis. In this review, we highlight new findings in the field of taste development, including how taste buds are patterned and how taste cell fate is regulated. We discuss whether a specialized taste bud stem cell population exists and how extrinsic signals can define which cell lineages are generated. We also address the question of whether molecular regulation of taste cell renewal is analogous to that of taste bud development. Finally, we conclude with suggestions for future directions, including the potential influence of the maternal diet and maternal health on the sense of taste in utero. © 2015 Elsevier Inc. All rights reserved.

The sweet cherry (Prunus avium) FLOWERING LOCUS T gene is expressed during floral bud determination and can promote flowering in a winter-annual Arabidopsis accession.

PubMed

Yarur, Antonia; Soto, Esteban; León, Gabriel; Almeida, Andrea Miyasaka

2016-12-01

FT gene is expressed in leaves and buds and is involved in floral meristem determination and bud development in sweet cherry. In woody fruit perennial trees, floral determination, dormancy and bloom, depends on perception of different environmental and endogenous cues which converge to a systemic signaling gene known as FLOWERING LOCUS T (FT). In long-day flowering plants, FT is expressed in the leaves on long days. The protein travels through the phloem to the shoot apical meristem, where it induces flower determination. In perennial plants, meristem determination and flowering are separated by a dormancy period. Meristem determination takes place in summer, but flowering occurs only after a dormancy period and cold accumulation during winter. The roles of FT are not completely clear in meristem determination, dormancy release, and flowering in perennial plants. We cloned FT from sweet cherry (Prunus avium) and analyzed its expression pattern in leaves and floral buds during spring and summer. Phylogenetic analysis shows high identity of the FT cloned sequence with orthologous genes from other Rosaceae species. Our results show that FT is expressed in both leaves and floral buds and increases when the daylight reached 12 h. The peak in FT expression was coincident with floral meristem identity genes expression and morphological changes typical of floral meristem determination. The Edi-0 Arabidopsis ecotype, which requires vernalization to flower, was transformed with a construct for overexpression of PavFT. These transgenic plants showed an early-flowering phenotype without cold treatment. Our results suggest that FT is involved in floral meristem determination and bud development in sweet cherry. Moreover, we show that FT is expressed in both leaves and floral buds in this species, in contrast to annual plants.

Bud removal affects shoot, root, and callus development of hardwood Populus cuttings

Treesearch

A.H. Wiese; J.A. Zalesny; D.M. Donner; Ronald S., Jr. Zalesny

2006-01-01

The inadvertent removal and/or damage of buds during processing and planting of hardwood poplar (Populus spp.) cuttings are a concern because of their potential impact on shoot and root development during establishment. The objective of the current study was to test for differences in shoot dry mass, root dry mass, number of roots, length of the...

Gene expression in spider appendages reveals reversal of exd/hth spatial specificity, altered leg gap gene dynamics, and suggests divergent distal morphogen signaling.

PubMed

Prpic, Nikola-Michael; Janssen, Ralf; Wigand, Barbara; Klingler, Martin; Damen, Wim G M

2003-12-01

Leg development in Drosophila has been studied in much detail. However, Drosophila limbs form in the larva as imaginal discs and not during embryogenesis as in most other arthropods. Here, we analyze appendage genes in the spider Cupiennius salei and the beetle Tribolium castaneum. Differences in decapentaplegic (dpp) expression suggest a different mode of distal morphogen signaling suitable for the specific geometry of growing limb buds. Also, expression of the proximal genes homothorax (hth) and extradenticle (exd) is significantly altered: in the spider, exd is restricted to the proximal leg and hth expression extends distally, while in insects, exd is expressed in the entire leg and hth is restricted to proximal parts. This reversal of spatial specificity demonstrates an evolutionary shift, which is nevertheless compatible with a conserved role of this gene pair as instructor of proximal fate. Different expression dynamics of dachshund and Distal-less point to modifications in the regulation of the leg gap gene system. We comment on the significance of this finding for attempts to homologize leg segments in different arthropod classes. Comparison of the expression profiles of H15 and optomotor-blind to the Drosophila patterns suggests modifications also in the dorsal-ventral patterning system of the legs. Together, our results suggest alterations in many components of the leg developmental system, namely proximal-distal and dorsal-ventral patterning, and leg segmentation. Thus, the leg developmental system exhibits a propensity to evolutionary change, which probably forms the basis for the impressive diversity of arthropod leg morphologies.

Variations of metabolites and proteome in Lonicera japonica Thunb. buds and flowers under UV radiation.

PubMed

Zhu, Wei; Zheng, Wen; Hu, Xingjiang; Xu, Xiaobao; Zhang, Lin; Tian, Jingkui

2017-04-01

Lonicera japonica Thunb., also known as Jin Yin Hua and Japanese honeysuckle, is used as a herbal medicine in Asian countries. Its flowers have been used in folk medicine in the clinic and in making food or healthy beverages for over 1500years in China. To investigate the molecular processes involved in L. japonica development from buds to flowers exposed to UV radiation, a comparative proteomics analysis was performed. Fifty-four proteins were identified as differentially expressed, including 42 that had increased expression and 12 that had decreased expression. The levels of the proteins related to glycolysis, TCA/organic acid transformation, major carbohydrate metabolism, oxidative pentose phosphate, stress, secondary metabolism, hormone, and mitochondrial electron transport were increased during flower opening process after exposure to UV radiation. Six metabolites in L. japonica buds and flowers were identified and relatively quantified using LC-MS/MS. The antioxidant activity was performed using a 1,1-diphenyl-2-picrylhydrazyl assay, which revealed that L. japonica buds had more activity than the UV irradiated flowers. This suggests that UV-B radiation induces production of endogenous ethylene in L. japonica buds, thus facilitating blossoming of the buds and activating the antioxidant system. Additionally, the higher metabolite contents and antioxidant properties of L. japonica buds indicate that the L. japonica bud stage may be a more optimal time to harvest than the flower stage when using for medicinal properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a Soluplus budesonide freeze-dried powder for nasal drug delivery.

PubMed

Pozzoli, Michele; Traini, Daniela; Young, Paul M; Sukkar, Maria B; Sonvico, Fabio

2017-09-01

The aim of this work was to develop an amorphous solid dispersions/solutions (ASD) of a poorly soluble drug, budesonide (BUD) with a novel polymer Soluplus ® (BASF, Germany) using a freeze-drying technique, in order to improve dissolution and absorption through the nasal route. The small volume of fluid present in the nasal cavity limits the absorption of a poorly soluble drug. Budesonide is a corticosteroid, practically insoluble and normally administered as a suspension-based nasal spray. The formulation was prepared through freeze-drying of polymer-drug solution. The formulation was assessed for its physicochemical (specific surface area, calorimetric analysis and X-ray powder diffraction), release properties and aerodynamic properties as well as transport in vitro using RPMI 2650 nasal cells, in order to elucidate the efficacy of the Soluplus-BUD formulation. The freeze-dried Soluplus-BUD formulation (LYO) showed a porous structure with a specific surface area of 1.4334 ± 0.0178 m 2 /g. The calorimetric analysis confirmed an interaction between BUD and Soluplus and X-ray powder diffraction the amorphous status of the drug. The freeze-dried formulation (LYO) showed faster release compared to both water-based suspension and dry powder commercial products. Furthermore, a LYO formulation, bulked with calcium carbonate (LYO-Ca), showed suitable aerodynamic characteristics for nasal drug delivery. The permeation across RPMI 2650 nasal cell model was higher compared to a commercial water-based BUD suspension. Soluplus has been shown to be a promising polymer for the formulation of BUD amorphous solid suspension/solution. This opens up opportunities to develop new formulations of poorly soluble drug for nasal delivery.

[Comparison of the botanic morphology and blooming characteristics of four cultivars of rose].

PubMed

Wang, Kang-cai; Tang, Xiao-qing; Sheng, Min-li; Xu, Xiao-lan; Fang, Zhen

2004-05-01

To establish identifying method for further development and utilization by studying botanic morphology and blooming characteristics of four varieties of roses in Jiangsu province. Flower-bud and flower-form were observed by dissection and plant modality and blooming process were investigated. The flower form and plant modality was obviously different among the 4 varieties of roses. The process of differentiation of flower-bud could be divided into five stages: the transformation of nutritive growth cone, the occurrence and development of sepal, formation of petal primordium, formation of pistil and stamen. The blooming process was made up of flower-bud period, display-petal period, initiating blooming period, blooming period, withering period and corresponding biological marks.

Laser capture microdissection to study flower morphogenesis

NASA Astrophysics Data System (ADS)

Pawełkowicz, Magdalena Ewa; Skarzyńska, Agnieszka; Kowalczuk, Cezary; PlÄ der, Wojciech; Przybecki, Zbigniew

2017-08-01

Laser Capture Microdissection (LCM) is a sample preparation microscopic method that enables isolation of an interesting cell or cells population from human, animal or plant tissue. This technique allows for obtaining pure sample from heterogeneous mixture. From isolated cells, it is possible to obtain the appropriate quality material used for genomic research in transcriptomics, proteomics and metabolomics. We used LCM method to study flower morphogenesis and specific bud's organ organization and development. The genes expression level in developing flower buds of male (B10) and female (2gg) lines were analyzed with qPCR. The expression was checked for stamen and carpel primordia obtained with LCM and for whole flower buds at successive stages of growth.

Role of Tulipa gesneriana TEOSINTE BRANCHED1 (TgTB1) in the control of axillary bud outgrowth in bulbs.

PubMed

Moreno-Pachon, Natalia M; Mutimawurugo, Marie-Chantal; Heynen, Eveline; Sergeeva, Lidiya; Benders, Anne; Blilou, Ikram; Hilhorst, Henk W M; Immink, Richard G H

2018-06-01

Tulip vegetative reproduction. Tulips reproduce asexually by the outgrowth of their axillary meristems located in the axil of each bulb scale. The number of axillary meristems in one bulb is low, and not all of them grow out during the yearly growth cycle of the bulb. Since the degree of axillary bud outgrowth in tulip determines the success of their vegetative propagation, this study aimed at understanding the mechanism controlling the differential axillary bud activity. We used a combined physiological and "bottom-up" molecular approach to shed light on this process and found that first two inner located buds do not seem to experience dormancy during the growth cycle, while mid-located buds enter dormancy by the end of the growing season. Dormancy was assessed by weight increase and TgTB1 expression levels, a conserved TCP transcription factor and well-known master integrator of environmental and endogenous signals influencing axillary meristem outgrowth in plants. We showed that TgTB1 expression in tulip bulbs can be modulated by sucrose, cytokinin and strigolactone, just as it has been reported for other species. However, the limited growth of mid-located buds, even when their TgTB1 expression is downregulated, points at other factors, probably physical, inhibiting their growth. We conclude that the time of axillary bud initiation determines the degree of dormancy and the sink strength of the bud. Thus, development, apical dominance, sink strength, hormonal cross-talk, expression of TgTB1 and other possibly physical but unidentified players, all converge to determine the growth capacity of tulip axillary buds.

Dormancy release of Norway spruce under climatic warming: testing ecophysiological models of bud burst with a whole-tree chamber experiment.

PubMed

Hänninen, Heikki; Slaney, Michelle; Linder, Sune

2007-02-01

Ecophysiological models predicting timing of bud burst were tested with data gathered from 40-year-old Norway spruce (Picea abies (L.) Karst.) trees growing in northern Sweden in whole-tree chambers under climatic conditions predicted to prevail in 2100. Norway spruce trees, with heights between 5 and 7 m, were enclosed in individual chambers that provided a factorial combination of ambient (365 micromol mol-1) or elevated (700 micromol mol-1) atmospheric CO2 concentration, [CO2], and ambient or elevated air temperature. Temperature elevation above ambient ranged from +2.8 degrees C in summer to +5.6 degrees C in winter. Compared with control trees, elevated air temperature hastened bud burst by 2 to 3 weeks, whereas elevated [CO2] had no effect on the timing of bud burst. A simple model based on the assumption that bud rest completion takes place on a fixed calendar day predicted timing of bud burst more accurately than two more complicated models in which bud rest completion is caused by accumulated chilling. Together with some recent studies, the results suggest that, in adult trees, some additional environmental cues besides chilling are required for bud rest completion. Although it appears that these additional factors will protect trees under predicted climatic warming conditions, increased risk of frost damage associated with earlier bud burst cannot be ruled out. Inconsistent and partially anomalous results obtained in the model fitting show that, in addition to phenological data gathered under field conditions, more specific data from growth chamber and greenhouse experiments are needed for further development and testing of the models.

Molecular profiling of tumour budding implicates TGFβ-mediated epithelial-mesenchymal transition as a therapeutic target in oral squamous cell carcinoma.

PubMed

Jensen, D H; Dabelsteen, E; Specht, L; Fiehn, A M K; Therkildsen, M H; Jønson, L; Vikesaa, J; Nielsen, F C; von Buchwald, C

2015-08-01

Although tumour budding is an adverse prognostic factor for many cancer types, the molecular mechanisms governing this phenomenon are incompletely understood. Therefore, understanding the molecular basis of tumour budding may provide new therapeutic and diagnostic options. We employ digital image analysis to demonstrate that the number of tumour buds in cytokeratin-stained sections correlates with patients having lymph node metastases at diagnosis. The tumour bud count was also a predictor of overall survival, independent of TNM stage. Tumour buds and paired central tumour areas were subsequently collected from oral squamous cell carcinoma (OSCC) specimens, using laser capture microdissection, and examined with RNA sequencing and miRNA-qPCR arrays. Compared with cells from the central parts of the tumours, budding cells exhibited a particular gene expression signature, comprising factors involved in epithelial-mesenchymal transition (EMT) and activated TGFβ signalling. Transcription factors ZEB1 and PRRX1 were up-regulated concomitantly with the decreased expression of mesenchymal-epithelial (MET) transcription factors (eg OVOL1) in addition to Krüppel-like factors and Grainyhead-like factors. Moreover, miR-200 family members were down-regulated in budding tumour cells. We used immunohistochemistry to validate five markers of the EMT/MET process in 199 OSCC tumours, as well as in situ hybridization in 20 OSCC samples. Given the strong relationship between tumour budding and the development of lymph node metastases and an adverse prognosis, therapeutics based on inhibiting the activation of TGFβ signalling may prove useful in the treatment of OSCC. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Effects of intratracheal budesonide during early postnatal life on lung maturity of premature fetal rabbits.

PubMed

Li, Ling; Yang, Chen; Feng, Xiuliang; Du, Yongping; Zhang, Zhihong; Zhang, Yueping

2018-01-01

This study aimed to study the effects of intratracheal instillation of budesonide on lung maturity of premature fetal rabbits. The developmental pattern of pulmonary alveoli in rabbits is similar to that in humans. Fetal rabbits were taken out from female rabbits on the 28th day of pregnancy (full term = 31 days) by cesarean section (c-section). The fetal rabbits were divided into four groups: control (normal saline, NS), budesonide (budesonide, BUD), calf pulmonary surfactant for injection (pulmonary surfactant, PS), and calf pulmonary surfactant + budesonide for injection (pulmonary surfactant + budesonide, PS + BUD). All premature rabbits were kept warm after c-section. After 15-min autonomous respiration, a tracheal cannula was implemented for instilling NS, BUD, PS, and PS + BUD. The morphology of lung tissues of premature fetal rabbits was analyzed using optical and electron microscopes. Surfactant protein B (SP-B) mRNA and protein levels in lung tissues were determined using polymerase chain reaction and Western blotting, respectively. Intratracheal instillation of BUD could increase the alveolar area of the fetal rabbits (P < 0.01), decrease the alveolar wall thickness (P < 0.01), and increase the mean density of lamellar bodies (P < 0.05) and SP-B protein levels in type II epithelial cells of pulmonary alveoli (P < 0.05). Intratracheal instillation of BUD during early postnatal life is effective in promoting alveolarization and increasing SP-B expression, the pro-pulmonary maturity of BUD combined with PS is superior to that of BUD or PS alone. However, the long-term effect of BUD on lung development needs further exploration. © 2017 Wiley Periodicals, Inc.

Real-time monitoring of the budding index in Saccharomyces cerevisiae batch cultivations with in situ microscopy.

PubMed

Marbà-Ardébol, Anna-Maria; Emmerich, Jörn; Muthig, Michael; Neubauer, Peter; Junne, Stefan

2018-05-15

The morphology of yeast cells changes during budding, depending on the growth rate and cultivation conditions. A photo-optical microscope was adapted and used to observe such morphological changes of individual cells directly in the cell suspension. In order to obtain statistically representative samples of the population without the influence of sampling, in situ microscopy (ISM) was applied in the different phases of a Saccharomyces cerevisiae batch cultivation. The real-time measurement was performed by coupling a photo-optical probe to an automated image analysis based on a neural network approach. Automatic cell recognition and classification of budding and non-budding cells was conducted successfully. Deviations between automated and manual counting were considerably low. A differentiation of growth activity across all process stages of a batch cultivation in complex media became feasible. An increased homogeneity among the population during the growth phase was well observable. At growth retardation, the portion of smaller cells increased due to a reduced bud formation. The maturation state of the cells was monitored by determining the budding index as a ratio between the number of cells, which were detected with buds and the total number of cells. A linear correlation between the budding index as monitored with ISM and the growth rate was found. It is shown that ISM is a meaningful analytical tool, as the budding index can provide valuable information about the growth activity of a yeast cell, e.g. in seed breeding or during any other cultivation process. The determination of the single-cell size and shape distributions provided information on the morphological heterogeneity among the populations. The ability to track changes in cell morphology directly on line enables new perspectives for monitoring and control, both in process development and on a production scale.

Abscisic acid signaling is controlled by a BRANCHED1/HD-ZIP I cascade in Arabidopsis axillary buds.

PubMed

González-Grandío, Eduardo; Pajoro, Alice; Franco-Zorrilla, José M; Tarancón, Carlos; Immink, Richard G H; Cubas, Pilar

2017-01-10

Shoot-branching patterns determine key aspects of plant life and are important targets for crop breeding. However, we are still largely ignorant of the genetic networks controlling locally the most important decision during branch development: whether the axillary bud, or branch primordium, grows out to give a lateral shoot or remains dormant. Here we show that, inside the buds, the TEOSINTE BRANCHED1, CYCLOIDEA, PCF (TCP) transcription factor BRANCHED1 (BRC1) binds to and positively regulates the transcription of three related Homeodomain leucine zipper protein (HD-ZIP)-encoding genes: HOMEOBOX PROTEIN 21 (HB21), HOMEOBOX PROTEIN 40 (HB40), and HOMEOBOX PROTEIN 53 (HB53). These three genes, together with BRC1, enhance 9-CIS-EPOXICAROTENOID DIOXIGENASE 3 (NCED3) expression, lead to abscisic acid accumulation, and trigger hormone response, thus causing suppression of bud development. This TCP/HD-ZIP genetic module seems to be conserved in dicot and monocotyledonous species to prevent branching under light-limiting conditions.

Development of guayule (Parthenium argentatum) research in cell culture

NASA Technical Reports Server (NTRS)

Ball, E. A.

1981-01-01

Utilizing the lateral buds of known high rubber producing plants as explants in culture medium specifically designed to engender shoot development and to prevent callus formation, unlimited numbers of replicate plants can be produced. Each has the same genotype as the parent. This procedure has long been used to rid plants of virus, the latter generally does not occur in the embryonic tissues of the bud; it also, by virtue of its axenic nature, eliminates all microorganisms characteristic of the parent plant. Auxins were found essential to callus formation, but since the latter is known to bring about chromosomal aberrations, it was avoided. The cytokinin benzylaminopurine strongly stimulated shoot growth, and the number of regenerated buds on the inoculum was proportional to its concentration. These buds produced shoots several centimeters in length which were caused to root on medium containing indolebutyric acid. Transferred to the septic condition of soil, the plantlets were gradually brought into full sunlight where they showed a brief vegetative growth with production of mature leaves, and flowered.

Project BudBurst: Continental-scale citizen science for all seasons

NASA Astrophysics Data System (ADS)

Henderson, S.; Newman, S. J.; Ward, D.; Havens-Young, K.; Alaback, P.; Meymaris, K.

2011-12-01

Project BudBurst's (budburst.org) recent move to the National Ecological Observatory Network (NEON) has benefitted both programs. NEON has been able to use Project BudBurst as a testbed to learn best practices, network with experts in the field, and prototype potential tools for engaging people in continental-scale ecology as NEON develops its citizen science program. Participation in Project BudBurst has grown significantly since the move to NEON. Project BudBurst is a national citizen science initiative designed to engage the public in observations of phenological (plant life cycle) events that raise awareness of climate change, and create a cadre of informed citizen scientists. Citizen science programs such as Project BudBurst provide the opportunity for students and interested laypersons to actively participate in scientific research. Such programs are important not only from an educational perspective, but because they also enable scientists to broaden the geographic and temporal scale of their observations. The goals of Project BudBurst are to 1) increase awareness of phenology as an area of scientific study; 2) Increase awareness of the impacts of changing climates on plants at a continental-scale; and 3) increase science literacy by engaging participants in the scientific process. From its 2008 launch in February, this on-line educational and data-entry program, engaged participants of all ages and walks of life in recording the timing of the leafing and flowering of wild and cultivated species found across the continent. Thus far, thousands of participants from all 50 states have submitted data. This presentation will provide an overview of Project BudBurst and will report on the results of the 2010 field campaign and discuss plans to expand Project BudBurst in 2012 including the use of mobile phones applications for data collection and reporting from the field. Project BudBurst is co-managed by the National Ecological Observatory Network and the Chicago Botanic Garden.

Resistance of Brachystegia spiciformis to Carbohydrate and Phenological Manipulation

NASA Astrophysics Data System (ADS)

Richer, R. A.

2006-12-01

Despite the development of metabolic ecology, the role that carbohydrate stores play in regulating phenological events is unknown. Whole tree manipulation experiments in the common southern African tree species, Brachystegia spiciformis offer new insights into the physiological and environmental mechanisms controlling bud break. This experiment tested a novel hypothesis that decreasing Total Non-Structural Carbohydrates (TNC) in the stem could cue bud break in Brachystegia spiciformis. The experimental treatments included fertilization, canopy defoliation, shading and stem heating and were repeated over a two year period in the Kalahari sand savanna system of northwestern Zimbabwe. The treatments were designed to decrease stem carbohydrates and result in an earlier leaf flush. None of the treatments significantly decreased seasonal stem TNC. Likewise the heating, fertilization and defoliation treatments did not significantly affect the date of bud break from controls. However, shaded trees showed a significant delay in bud break. This delay in bud break could not be attributed to leaf level photosynthetic traits, stem water content, leaf pre-dawn water potential or delayed leaf fall. These results question widely accepted hypotheses about the mechanism controlling bud break in savanna ecosystems and may suggest a carbohydrate homeostatic mechanism.

Dynamic thermal-time model of cold hardiness for dormant grapevine buds

USDA-ARS?s Scientific Manuscript database

Grapevine (Vitis spp.) cold hardiness varies dynamically throughout the dormant season, primarily in response to changes in temperature. We describe development and possible uses of a discrete-dynamic model of bud cold hardiness for three Vitis genotypes. Iterative methods were used to optimize and ...

Susceptibility of blackberry flowers to freezing temperatures

USDA-ARS?s Scientific Manuscript database

Injury of tight buds, open flowers and green fruit often occur in fruit crops during spring frost events. In this study, freezing tolerance of ‘Triple Crown’ blackberry flowers at different reproductive stages of development (tight bud to green drupe) was determined using two methods. One method i...

Selective Entrapment of Extrachromosomally Amplified DNA by Nuclear Budding and Micronucleation during S Phase

PubMed Central

Shimizu, Noriaki; Itoh, Nobuo; Utiyama, Hiroyasu; Wahl, Geoffrey M.

1998-01-01

Acentric, autonomously replicating extrachromosomal structures called double-minute chromosomes (DMs) frequently mediate oncogene amplification in human tumors. We show that DMs can be removed from the nucleus by a novel micronucleation mechanism that is initiated by budding of the nuclear membrane during S phase. DMs containing c-myc oncogenes in a colon cancer cell line localized to and replicated at the nuclear periphery. Replication inhibitors increased micronucleation; cell synchronization and bromodeoxyuridine–pulse labeling demonstrated de novo formation of buds and micronuclei during S phase. The frequencies of S-phase nuclear budding and micronucleation were increased dramatically in normal human cells by inactivating p53, suggesting that an S-phase function of p53 minimizes the probability of producing the broken chromosome fragments that induce budding and micronucleation. These data have implications for understanding the behavior of acentric DNA in interphase nuclei and for developing chemotherapeutic strategies based on this new mechanism for DM elimination. PMID:9508765

Differences in respiration between dormant and non-dormant buds suggest the involvement of ABA in the development of endodormancy in grapevines.

PubMed

Parada, Francisca; Noriega, Ximena; Dantas, Débora; Bressan-Smith, Ricardo; Pérez, Francisco J

2016-08-20

Grapevine buds (Vitis vinifera L) enter endodormancy (ED) after perceiving the short-day (SD) photoperiod signal and undergo metabolic changes that allow them to survive the winter temperatures. In the present study, we observed an inverse relationship between the depth of ED and the respiration rate of grapevine buds. Moreover, the respiration of dormant and non-dormant buds differed in response to temperature and glucose, two stimuli that normally increase respiration in plant tissues. While respiration in non-dormant buds rose sharply in response to both stimuli, respiration in dormant buds was only slightly affected. This suggests that a metabolic inhibitor is present. Here, we propose that the plant hormone abscisic acid (ABA) could be this inhibitor. ABA inhibits respiration in non-dormant buds and represses the expression of respiratory genes, such as ALTERNATIVE NADH DEHYDROGENASE (VaND1, VvaND2), CYTOCHROME OXIDASE (VvCOX6) and CYTOCHROME C (VvCYTC), and induces the expression of VvSnRK1, a gene encoding a member of a highly conserved family of protein kinases that act as energy sensors and regulate gene expression in response to energy depletion. In addition to inducing ED the SD-photoperiod up-regulated the expression of VvNCED, a gene that encodes a key enzyme in ABA synthesis. Taken together, these results suggest that ABA through the mediation of VvSnRK1, could play a key role in the regulation of the metabolic changes accompanying the entry into ED of grapevine buds. Copyright © 2016 Elsevier GmbH. All rights reserved.

Identifying genes that extend life span using a high-throughput screening system.

PubMed

Chen, Cuiying; Contreras, Roland

2007-01-01

We developed a high-throughput functional genomic screening system that allows identification of genes prolonging lifespan in the baker's yeast Saccharomyces cerevisiae. The method is based on isolating yeast mother cells with a higher than average number of cell divisions as indicated by the number of bud scars on their surface. Fluorescently labeled wheat germ agglutinin (WGA) was used for specific staining of chitin, a major component of bud scars. The critical new steps in our bud-scar-sorting system are the use of small microbeads, which allows successive rounds of purification and regrowth of the mother cells (M-cell), and utilization of flow cytometry to sort and isolate cells with a longer lifespan based on the number of bud scars specifically labeled with WGA.

Developmental stages of cultivated strawberry flowers in relation to chilling sensitivity

PubMed Central

Ariza, Maria Teresa; Soria, Carmen; Martínez-Ferri, Elsa

2015-01-01

Environmental factors affecting flower development may limit the yields of fruiting crops worldwide. In temperate regions, chilling temperatures during flower development can compromise fruit production, but their negative effects vary depending on the differing susceptibilities of each developmental stage. The cultivated strawberry (Fragaria× ananassa Duch.) is widely grown worldwide but financial returns are influenced by sudden shifts to chilling temperatures occurring during the cropping cycle. Despite this important limitation, knowledge of F.× ananassa flower development is lacking, in contrast to the diploid wild-type strawberry (F. vesca). In this study we describe steps in floral development of cultivated strawberry and define their vulnerability to chilling temperatures. To achieve this, flower buds from strawberry plants of cv. ‘Camarosa’ were labelled and monitored from bud initiation until anthesis. Description of morphological and functional changes during flower development was based on histological sections and scanning electron microscopy. To determine the impact of low temperatures at different developmental stages, plants carrying buds of different sizes were chilled at 2 °C for 24 h. Several parameters related to male and female gametophyte development were later evaluated in flowers as they approached anthesis. Fragaria× ananassa flower development was divided into 16 stages according to landmark events. These stages were similar to those documented for F. vesca but three new additional intermediate stages were described. Timing of developmental processes was achieved by correlating developmental staging with specific bud sizes and days before anthesis. Time to reach anthesis from early bud stages was 17–18 days. During this period, we detected four critical periods vulnerable to low temperatures. These were mostly related to male gametophyte development but also to injury to female organs at late developmental stages. These results provide the essential groundwork on floral biology of cultivated strawberry that is a prerequisite for successful comparative studies of cold tolerance among genotypes during flower formation. PMID:25661200

Subtype-dependent postnatal development of taste receptor cells in mouse fungiform taste buds.

PubMed

Ohtubo, Yoshitaka; Iwamoto, Masafumi; Yoshii, Kiyonori

2012-06-01

Taste buds contain two types of taste receptor cells, inositol 1,4,5-triphosphate receptor type 3-immunoreactive cells (type II cells) and synaptosomal-associating protein-25-immunoreactive cells (type III cells). We investigated their postnatal development in mouse fungiform taste buds immunohistochemically and electrophysiologically. The cell density, i.e. the number of cells per taste bud divided by the maximal area of the horizontal cross-section of the taste bud, of type II cells increased by postnatal day (PD)49, where as that of type III cells was unchanged throughout the postnatal observation period and was equal to that of the adult cells at PD1. The immunoreactivity of taste bud cell subtypes was the same as that of their respective subtypes in adult mice throughout the postnatal observation period. Almost all type II cells were immunoreactive to gustducin at PD1, and then the ratio of gustducin-immunoreactive type II cells to all type II cells decreased to a saturation level, ∼60% of all type II cells, by PD15. Type II and III cells generated voltage-gated currents similar to their respective adult cells even at PD3. These results show that infant taste receptor cells are as excitable as those of adults and propagate in a subtype-dependent manner. The relationship between the ratio of each taste receptor cell subtype to all cells and taste nerve responses are discussed. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Signaling Cascades Governing Cdc42-Mediated Chondrogenic Differentiation and Mensenchymal Condensation.

PubMed

Wang, Jirong R; Wang, Chaojun J; Xu, Chengyun Y; Wu, Xiaokai K; Hong, Dun; Shi, Wei; Gong, Ying; Chen, Haixiao X; Long, Fanxin; Wu, Ximei M

2016-03-01

Endochondral ossification consists of successive steps of chondrocyte differentiation, including mesenchymal condensation, differentiation of chondrocytes, and hypertrophy followed by mineralization and ossification. Loss-of-function studies have revealed that abnormal growth plate cartilage of the Cdc42 mutant contributes to the defects in endochondral bone formation. Here, we have investigated the roles of Cdc42 in osteogenesis and signaling cascades governing Cdc42-mediated chondrogenic differentiation. Though deletion of Cdc42 in limb mesenchymal progenitors led to severe defects in endochondral ossification, either ablation of Cdc42 in limb preosteoblasts or knockdown of Cdc42 in vitro had no obvious effects on bone formation and osteoblast differentiation. However, in Cdc42 mutant limb buds, loss of Cdc42 in mesenchymal progenitors led to marked inactivation of p38 and Smad1/5, and in micromass cultures, Cdc42 lay on the upstream of p38 to activate Smad1/5 in bone morphogenetic protein-2-induced mesenchymal condensation. Finally, Cdc42 also lay on the upstream of protein kinase B to transactivate Sox9 and subsequently induced the expression of chondrocyte differential marker in transforming growth factor-β1-induced chondrogenesis. Taken together, by using biochemical and genetic approaches, we have demonstrated that Cdc42 is involved not in osteogenesis but in chondrogenesis in which the BMP2/Cdc42/Pak/p38/Smad signaling module promotes mesenchymal condensation and the TGF-β/Cdc42/Pak/Akt/Sox9 signaling module facilitates chondrogenic differentiation. Copyright © 2016 by the Genetics Society of America.

Floral Initiation in Response to Planting Date Reveals the Key Role of Floral Meristem Differentiation Prior to Budding in Canola (Brassica napus L.).

PubMed

Zhang, Yaofeng; Zhang, Dongqing; Yu, Huasheng; Lin, Baogang; Fu, Ying; Hua, Shuijin

2016-01-01

In Brassica napus, floral development is a decisive factor in silique formation, and it is influenced by many cultivation practices including planting date. However, the effect of planting date on floral initiation in canola is poorly understood at present. A field experiment was conducted using a split plot design, in which three planting dates (early, 15 September, middle, 1 October, and late, 15 October) served as main plot and five varieties differing in maturity (1358, J22, Zhongshuang 11, Zheshuang 8, and Zheyou 50) employed as subplot. The purpose of this study was to shed light on the process of floral meristem (FM) differentiation, the influence of planting date on growth period (GP) and floral initiation, and silique formation. The main stages of FM developments can be divided into four stages: first, the transition from shoot apical meristem to FM; second, flower initiation; third, gynoecium and androecium differentiation; and fourth, bud formation. Our results showed that all genotypes had increased GPs from sowing to FM differentiation as planting date was delayed while the GPs from FM differentiation to budding varied year by year except the very early variety, 1358. Based on the number of flowers present at the different reproductive stages, the flowers produced from FM differentiation to budding closely approximated the final silique even though the FM differentiated continuously after budding and peaked generally at the middle flowering stage. The ratio of siliques to maximum flower number ranged from 48 to 80%. These results suggest that (1) the period from FM differentiation to budding is vital for effective flower and silique formation although there was no significant correlation between the length of the period and effective flowers and siliques, and (2) the increased number of flowers from budding were generally ineffective. Therefore, maximizing flower numbers prior to budding will improve silique numbers, and reducing FM degeneration should also increase final silique formation. From the results of our study, we offer guidelines for planting canola varieties that differ in maturity in order to maximize effective flower numbers.

Analysis of Rhizome Development in Oryza longistaminata, a Wild Rice Species.

PubMed

Yoshida, Akiko; Terada, Yasuhiko; Toriba, Taiyo; Kose, Katsumi; Ashikari, Motoyuki; Kyozuka, Junko

2016-10-01

Vegetative reproduction is a form of asexual propagation in plants. A wide range of plants develop rhizomes, modified stems that grow underground horizontally, as a means of vegetative reproduction. In rhizomatous species, despite their distinct developmental patterns, both rhizomes and aerial shoots derive from axillary buds. Therefore, it is of interest to understand the basis of rhizome initiation and development. Oryza longistaminata, a wild rice species, develops rhizomes. We analyzed bud initiation and growth of O. longistaminata rhizomes using various methods of morphological observation. We show that, unlike aerial shoot buds that contain a few leaves only, rhizome buds initiate several leaves and bend to grow at right angles to the original rhizome. Rhizomes are maintained in the juvenile phase irrespective of the developmental phase of the aerial shoot. Stem elongation and reproductive transition are tightly linked in the aerial shoots, but are uncoupled in the rhizome. Our findings indicate that developmental programs operate independently in the rhizomes and aerial shoots. Temporal modification of the developmental pathways that are common to rhizomes and aerial shoots may be the source of developmental plasticity. Furthermore, the creation of new developmental systems appears to be necessary for rhizome development. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Bud-bank and tiller dynamics of co-occurring C3 caespitose grasses in mixed-grass prairie.

PubMed

Ott, Jacqueline P; Hartnett, David C

2015-09-01

Tiller recruitment from the belowground bud bank of caespitose grasses influences their ability to monopolize local resources and, hence, their genet fitness. Differences in bud production and outgrowth among tiller types within a genet and among species may explain co-occurrence of caespitose grasses. This study aimed to characterize genet bud-bank and tiller production and dynamics in two co-occurring species and compare their vegetative reproductive strategies. Bud-bank and tiller dynamics of Hesperostipa comata and Nassella viridula, dominant C3 caespitose grasses in the northern mixed-grass prairie of North America, were assessed throughout an annual cycle. The two species showed similar strategies, maintaining polycyclic tillers and thus creating mixed-age genet bud banks comprising multiple bud cohorts produced in different years. Vegetative tillers produced the majority of buds, whereas flowering tillers contributed little to the bud bank. Buds lived for at least 2 yr and were maintained in multiple developmental stages throughout the year. Because bud longevity rarely exceeded tiller longevity, tiller longevity drove turnover within the bud bank. Tiller population dynamics, more than bud production per tiller, determined the differential contribution of tiller types to the bud bank. Nassella viridula had higher bud production per tiller, a consistent annual tiller recruitment density, and greater longevity of buds on senesced and flowering tillers than H. comata. Co-occurring C3 caespitose grasses had similar bud-bank and tiller dynamics contributing to genet persistence but differed in bud characteristics that could affect genet longevity and species coexistence. © 2015 Botanical Society of America.

Budesonide-Loaded Guar Gum Microspheres for Colon Delivery: Preparation, Characterization and in Vitro/in Vivo Evaluation

PubMed Central

Liu, Ye; Zhou, Hong

2015-01-01

A novel budesonide (BUD) colon delivery release system was developed by using a natural polysaccharide, guar gum. The rigidity of the microspheres was induced by a chemical cross-linking method utilizing glutaraldehyde as the cross-linker. The mean particle size of the microspheres prepared was found to be 15.21 ± 1.32 µm. The drug loading and entrapment efficiency of the formulation were 17.78% ± 2.31% and 81.6% ± 5.42%, respectively. The microspheres were spherical in shape with a smooth surface, and the size was uniform. The in vitro release profiles indicated that the release of BUD from the microspheres exhibited a sustained release behavior. The model that fitted best for BUD released from the microspheres was the Higuchi kinetic model with a correlation coefficient r = 0.9993. A similar phenomenon was also observed in a pharmacokinetic study. The prolongation of the half-life (t1/2), enhanced residence time (mean residence time, MRT) and decreased total clearance (CL) indicated that BUD microspheres could prolong the acting time of BUD in vivo. In addition, BUD guar gum microspheres are thought to have the potential to maintain BUD concentration within target ranges for a long time, decreasing the side effects caused by concentration fluctuation, ensuring the efficiency of treatment and improving patient compliance by reducing dosing frequency. None of the severe signs, like the appearance of epithelial necrosis and the sloughing of epithelial cells, were detected. PMID:25629228

Fgf signaling controls pharyngeal taste bud formation through miR-200 and Delta-Notch activity.

PubMed

Kapsimali, Marika; Kaushik, Anna-Lila; Gibon, Guillaume; Dirian, Lara; Ernest, Sylvain; Rosa, Frederic M

2011-08-01

Taste buds, the taste sensory organs, are conserved in vertebrates and composed of distinct cell types, including taste receptor, basal/presynaptic and support cells. Here, we characterize zebrafish taste bud development and show that compromised Fgf signaling in the larva results in taste bud reduction and disorganization. We determine that Fgf activity is required within pharyngeal endoderm for formation of Calb2b(+) cells and reveal miR-200 and Delta-Notch signaling as key factors in this process. miR-200 knock down shows that miR-200 activity is required for taste bud formation and in particular for Calb2b(+) cell formation. Compromised delta activity in mib(-/-) dramatically reduces the number of Calb2b(+) cells and increases the number of 5HT(+) cells. Conversely, larvae with increased Notch activity and ascl1a(-/-) mutants are devoid of 5HT(+) cells, but have maintained and increased Calb2b(+) cells, respectively. These results show that Delta-Notch signaling is required for intact taste bud organ formation. Consistent with this, Notch activity restores Calb2b(+) cell formation in pharyngeal endoderm with compromised Fgf signaling, but fails to restore the formation of these cells after miR-200 knock down. Altogether, this study provides genetic evidence that supports a novel model where Fgf regulates Delta-Notch signaling, and subsequently miR-200 activity, in order to promote taste bud cell type differentiation.

Progress and renewal in gustation: new insights into taste bud development

PubMed Central

Barlow, Linda A.

2015-01-01

The sense of taste, or gustation, is mediated by taste buds, which are housed in specialized taste papillae found in a stereotyped pattern on the surface of the tongue. Each bud, regardless of its location, is a collection of ∼100 cells that belong to at least five different functional classes, which transduce sweet, bitter, salt, sour and umami (the taste of glutamate) signals. Taste receptor cells harbor functional similarities to neurons but, like epithelial cells, are rapidly and continuously renewed throughout adult life. Here, I review recent advances in our understanding of how the pattern of taste buds is established in embryos and discuss the cellular and molecular mechanisms governing taste cell turnover. I also highlight how these findings aid our understanding of how and why many cancer therapies result in taste dysfunction. PMID:26534983

Vegetative regeneration of invasive Ludwigia cytotypes from clonal bud banks across resource gradients: colonizing diploid outperforms polyploid

USDA-ARS?s Scientific Manuscript database

Understanding functional traits that underlie the colonization of invasive plants is key to developing sustainable management strategies to curtail invasions at the establishment phase. Although common, recruitment of clonal plant species from bud banks is often overlooked but may be a key transiti...

Identification of a new androgen receptor (AR) co-regulator BUD31 and related peptides to suppress wild-type and mutated AR-mediated prostate cancer growth via peptide screening and X-ray structure analysis.

PubMed

Hsu, Cheng-Lung; Liu, Jai-Shin; Wu, Po-Long; Guan, Hong-Hsiang; Chen, Yuh-Ling; Lin, An-Chi; Ting, Huei-Ju; Pang, See-Tong; Yeh, Shauh-Der; Ma, Wen-Lung; Chen, Chung-Jung; Wu, Wen-Guey; Chang, Chawnshang

2014-12-01

Treatment with individual anti-androgens is associated with the development of hot-spot mutations in the androgen receptor (AR). Here, we found that anti-androgens-mt-ARs have similar binary structure to the 5α-dihydrotestosterone-wt-AR. Phage display revealed that these ARs bound to similar peptides, including BUD31, containing an Fxx(F/H/L/W/Y)Y motif cluster with Tyr in the +5 position. Structural analyses of the AR-LBD-BUD31 complex revealed formation of an extra hydrogen bond between the Tyr+5 residue of the peptide and the AR. Functional studies showed that BUD31-related peptides suppressed AR transactivation, interrupted AR N-C interaction, and suppressed AR-mediated cell growth. Combination of peptide screening and X-ray structure analysis may serve as a new strategy for developing anti-ARs that simultaneously suppress both wt and mutated AR function. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

In vivo imaging of basement membrane movement: ECM patterning shapes Hydra polyps.

PubMed

Aufschnaiter, Roland; Zamir, Evan A; Little, Charles D; Özbek, Suat; Münder, Sandra; David, Charles N; Li, Li; Sarras, Michael P; Zhang, Xiaoming

2011-12-01

Growth and morphogenesis during embryonic development, asexual reproduction and regeneration require extensive remodeling of the extracellular matrix (ECM). We used the simple metazoan Hydra to examine the fate of ECM during tissue morphogenesis and asexual budding. In growing Hydra, epithelial cells constantly move towards the extremities of the animal and into outgrowing buds. It is not known, whether these tissue movements involve epithelial migration relative to the underlying matrix or whether cells and ECM are displaced as a composite structure. Furthermore, it is unclear, how the ECM is remodeled to adapt to the shape of developing buds and tentacles. To address these questions, we used a new in vivo labeling technique for Hydra collagen-1 and laminin, and tracked the fate of ECM in all body regions of the animal. Our results reveal that Hydra 'tissue movements' are largely displacements of epithelial cells together with associated ECM. By contrast, during the evagination of buds and tentacles, extensive movement of epithelial cells relative to the matrix is observed, together with local ECM remodeling. These findings provide new insights into the nature of growth and morphogenesis in epithelial tissues.

Characterisation of phenolic compounds by HPLC-TOF/IT/MS in buds and open flowers of 'Chemlali' olive cultivar.

PubMed

Taamalli, Amani; Abaza, Leila; Arráez Román, David; Segura Carretero, Antonio; Fernández Gutiérrez, Alberto; Zarrouk, Mokhtar; Nabil, Ben Youssef

2013-01-01

Plant phenolics are secondary metabolites that constitute one of the most widely occurring groups of phytochemicals that play several important functions in plants. In olive (Olea europaea L), there is not enough information about the occurrence of these compounds in buds and flowers. To conduct a comprehensive characterisation of buds and open flowers from the olive cultivar 'Chemlali'. The polar fraction of buds and open flowers was extracted using solid-liquid extraction with hydro-alcoholic solvent. Then extracts were analysed using high performance liquid chromatography (HPLC) coupled to electrospray ionisation time-of-flight mass spectrometry (ESI/TOF/MS) and electrospray ionisation ion-trap tandem mass spectrometry (ESI/IT/MS²) operating in negative ion mode. Phenolic compounds from different classes including secoiridoids, flavonoids, simple phenols, cinnamic acid derivatives and lignans were tentatively identified in both extracts. Qualitatively, no significant difference was observed between flower buds and open flowers extracts. However, quantitatively the secoiridoids presented higher percentage of total phenols in open flowers (41.7%) than in flower buds (30.5%) in contrast to flavonoids, which decreased slightly from 38.1 to 26.7%. Cinnamic acid derivatives and simple phenols did not show any change. Lignans presented the lowest percentage in both extracts with an increase during the development of the flower bud to open flower. The HPLC-TOF/IT/MS allowed the characterisation, for the first time, of the phenolic profile of extracts of 'Chemlali' olive buds and open flowers, proving to be a very useful technique for the characterisation and structure elucidation of phenolic compounds. Copyright © 2013 John Wiley & Sons, Ltd.

High biological variability of plastids, photosynthetic pigments and pigment forms of leaf primordia in buds.

PubMed

Solymosi, Katalin; Morandi, Dominique; Bóka, Károly; Böddi, Béla; Schoefs, Benoît

2012-05-01

To study the formation of the photosynthetic apparatus in nature, the carotenoid and chlorophyllous pigment compositions of differently developed leaf primordia in closed and opening buds of common ash (Fraxinus excelsior L.) and horse chestnut (Aesculus hippocastanum L.) as well as in closed buds of tree of heaven (Ailanthus altissima P. Mill.) were analyzed with HPLC. The native organization of the chlorophyllous pigments was studied using 77 K fluorescence spectroscopy, and plastid ultrastructure was investigated with electron microscopy. Complete etiolation, i.e., accumulation of protochlorophyllide, and absence of chlorophylls occurred in the innermost leaf primordia of common ash buds. The other leaf primordia were partially etiolated in the buds and contained protochlorophyllide (0.5-1 μg g(-1) fresh mass), chlorophyllides (0.2-27 μg g(-1) fresh mass) and chlorophylls (0.9-643 μg g(-1) fresh mass). Etio-chloroplasts with prolamellar bodies and either regular or only low grana were found in leaves having high or low amounts of chlorophyll a and b, respectively. After bud break, etioplast-chloroplast conversion proceeded and the pigment contents increased in the leaves, similarly to the greening processes observed in illuminated etiolated seedlings under laboratory conditions. The pigment contents and the ratio of the different spectral forms had a high biological variability that could be attributed to (i) various light conditions due to light filtering in the buds resulting in differently etiolated leaf primordia, (ii) to differences in the light-exposed and inner regions of the same primordia in opening buds due to various leaf folding, and (iii) to tissue-specific slight variations of plastid ultrastructure.

New phenotypes generated by the G57R mutation of BUD23 in Saccharomyces cerevisiae.

PubMed

Lin, Jyun-Liang; Yu, Hui-Chia; Chao, Ju-Lan; Wang, Chung; Cheng, Ming-Yuan

2012-12-01

BUD23 in Saccharomyces cerevisiae encodes for a class I methyltransferase, and deletion of the gene results in slow growth and random budding phenotypes. Herein, two BUD23 mutants defective in methyltransferase activity were generated to investigate whether the phenotypes of the null mutant might be correlated with a loss in enzymatic activity. Expression at the physiological level of both D77A and G57R mutants was able to rescue the phenotypes of the bud23-null mutant. The result implied that the methyltransferase activity of the protein was not necessary for supporting normal growth and bud site selection of the cells. High-level expression of Bud23 (G57R), but not Bud23 or Bud23 (D77A), in BUD23 deletion cells failed to complement these phenotypes. However, just like Bud23, Bud23 (G57R) was localized in a DAPI-poor region in the nucleus. Distinct behaviour in Bud23 (G57R) could not be originated from a mislocalization of the protein. Over-expression of Bud23 (G57R) in null cells also produced changes in actin organization and additional septin mutant-like phenotypes. Therefore, the absence of Bud23, Bud23 (G57R) at a high level might affect the cell division of yeast cells through an as yet unidentified mechanism. Copyright © 2012 John Wiley & Sons, Ltd.

Morpho-anatomical features of underground systems in six Asteraceae species from the Brazilian Cerrado.

PubMed

Appezzato-da-Glória, Beatriz; Cury, Graziela

2011-09-01

In the Brazilian Cerrado (neotropical savanna), the development of bud-bearing underground systems as adaptive structures to fire and dry periods can comprise an important source of buds for this ecosystem, as already demonstrated in the Brazilian Campos grasslands and North American prairies. Asteraceae species from both woody and herbaceous strata have subterranean organs that accumulate carbohydrates, reinforcing the adaptive strategy of these plants to different environmental conditions. This study aims to analyse the morpho-anatomy of underground systems of six species of Asteraceae (Mikania cordifolia L.f. Willd., Mikania sessilifolia DC, Trixis nobilis (Vell.) Katinas, Pterocaulon alopecuroides (Lam.) DC., Vernonia elegans Gardner and Vernonia megapotamica Spreng.), to describe these structures and to verify the occurrence and origin of shoot buds, and to analyse the presence of reserve substances. Individuals sampled in Cerrado areas in São Paulo State showed thick underground bud-bearing organs, with adventitious or lateral roots and presence of fructans. Xylopodium was found in all studied species, except for Trixis nobilis, which had stem tuber. The presence of fructans as reserve, and the capacity of structures in the formation of buds indicate the potential of herbaceous species of Asteraceae in forming a viable bud bank for vegetation regeneration in the Brazilian Cerrado.

Productive potential of cassava plants (Manihot esculenta Crantz) propagated by leaf buds.

PubMed

Neves, Reizaluamar J; Diniz, Rafael P; Oliveira, Eder J DE

2018-04-23

New techniques of rapid multiplication of cassava (Manihot esculenta Crantz) have been developed, requiring technical support for large-scale use. This work main to evaluate the agronomic performance of plantlets obtained by leaf buds technique against stem cuttings in the field conditions. The work was conducted using the randomized block design in a factorial scheme with 3 varieties (BRS Kiriris, 98150-06, 9624-09) × 4 origins of the plantlets (conventional - stem cuttings of 20 cm length, leaf buds of the upper, middle and inferior stem part) × 2 agrochemicals (control and treated). There was a remarkable decrease in some agronomic traits that ranged from 23% (number of branches) to 62% (shoot weight) when using leaf buds plantlets. The treatment of plantlets with agrochemicals promoted significant increases in all traits, ranging from 26% (number of roots per plant) to 46% (shoot weight). The plantlets originating from leaf buds of the upper and middle parts were able to generate stem-like plants similar to stem-derived ones. Despite its lower agronomic performance under field conditions, multiplication by leaf buds may generate five times the number of propagules in comparison with the conventional multiplication, and therefore it could be a viable alternative for rapid cassava multiplication.

Continuous development precludes radioprotection in a colonial ascidian.

PubMed

Laird, Diana J; Weissman, Irving L

2004-03-01

Colonial organisms provide a unique experimental system for stem cell biology. The colonial Urochordate Botryllus schlosseri reproduces sexually as well as by continuous asexual budding. Adjacent colonies with a shared histocompatibility allele undergo vascular fusion and establish a common blood circulation, performing natural transplantation. Fused colonies become chimeras, often with complete somatic replacement of the host cell genotype by the fused parabiont. We attempted to establish a radioprotection assay for the somatic stem cells that induce long-term chimerism in Botryllus. We demonstrate over a range of radiation doses that neither autologous nor allogeneic cell transplantation enhances survival of host colonies. This suggests that high mitotic index associated with continuous asexual development leads to radiosensitivity of organs and structures essential to survival during engraftment. We observe that radiation induces uncontrolled epithelial cell proliferation in abnormally terminated buds, suggesting that stem cells are not required for the initial stages of bud development.

The lateral mesodermal divide: an epigenetic model of the origin of paired fins.

PubMed

Nuño de la Rosa, Laura; Müller, Gerd B; Metscher, Brian D

2014-01-01

By examining development at the level of tissues and processes, rather than focusing on gene expression, we have formulated a general hypothesis to explain the dorso-ventral and anterior-posterior placement of paired appendage initiation sites in vertebrates. According to our model, the number and position of paired appendages are due to a commonality of embryonic tissue environments determined by the global interactions involving the two separated layers (somatic and visceral) of lateral plate mesoderm along the dorso-ventral and anterior-posterior axes of the embryo. We identify this distribution of developmental conditions, as modulated by the separation/contact of the two LPM layers and their interactions with somitic mesoderm, ectoderm, and endoderm as a dynamic developmental entity which we have termed the lateral mesodermal divide (LMD). Where the divide results in a certain tissue environment, fin bud initiation can occur. According to our hypothesis, the influence of the developing gut suppresses limb initiation along the midgut region and the ventral body wall owing to an "endodermal predominance." From an evolutionary perspective, the lack of gut regionalization in agnathans reflects the ancestral absence of these conditions, and the elaboration of the gut together with the concomitant changes to the LMD in the gnathostomes could have led to the origin of paired fins. © 2013 Wiley Periodicals, Inc.

A high-resolution genetic, physical, and comparative gene map of the doublefoot (Dbf) region of mouse chromosome 1 and the region of conserved synteny on human chromosome 2q35.

PubMed

Hayes, C; Rump, A; Cadman, M R; Harrison, M; Evans, E P; Lyon, M F; Morriss-Kay, G M; Rosenthal, A; Brown, S D

2001-12-01

The mouse doublefoot (Dbf) mutant exhibits preaxial polydactyly in association with craniofacial defects. This mutation has previously been mapped to mouse chromosome 1. We have used a positional cloning strategy, coupled with a comparative sequencing approach using available human draft sequence, to identify putative candidates for the Dbf gene in the mouse and in homologous human region. We have constructed a high-resolution genetic map of the region, localizing the mutation to a 0.4-cM (+/-0.0061) interval on mouse chromosome 1. Furthermore, we have constructed contiguous BAC/PAC clone maps across the mouse and human Dbf region. Using existing markers and additional sequence tagged sites, which we have generated, we have anchored the physical map to the genetic map. Through the comparative sequencing of these clones we have identified 35 genes within this interval, indicating that the region is gene-rich. From this we have identified several genes that are known to be differentially expressed in the developing mid-gestation mouse embryo, some in the developing embryonic limb buds. These genes include those encoding known developmental signaling molecules such as WNT proteins and IHH, and we provide evidence that these genes are candidates for the Dbf mutation.

Comparative Genomics Reveals Accelerated Evolution in Conserved Pathways during the Diversification of Anole Lizards

PubMed Central

Tollis, Marc; Hutchins, Elizabeth D; Stapley, Jessica; Rupp, Shawn M; Eckalbar, Walter L; Maayan, Inbar; Lasku, Eris; Infante, Carlos R; Dennis, Stuart R; Robertson, Joel A; May, Catherine M; Bermingham, Eldredge; DeNardo, Dale F; Hsieh, Shi-Tong Tonia; Kulathinal, Rob J; McMillan, William Owen; Menke, Douglas B; Pratt, Stephen C; Rawls, Jeffery Alan; Sanjur, Oris; Wilson-Rawls, Jeanne; Wilson Sayres, Melissa A; Fisher, Rebecca E

2018-01-01

Abstract Squamates include all lizards and snakes, and display some of the most diverse and extreme morphological adaptations among vertebrates. However, compared with birds and mammals, relatively few resources exist for comparative genomic analyses of squamates, hampering efforts to understand the molecular bases of phenotypic diversification in such a speciose clade. In particular, the ∼400 species of anole lizard represent an extensive squamate radiation. Here, we sequence and assemble the draft genomes of three anole species—Anolis frenatus, Anolis auratus, and Anolis apletophallus—for comparison with the available reference genome of Anolis carolinensis. Comparative analyses reveal a rapid background rate of molecular evolution consistent with a model of punctuated equilibrium, and strong purifying selection on functional genomic elements in anoles. We find evidence for accelerated evolution in genes involved in behavior, sensory perception, and reproduction, as well as in genes regulating limb bud development and hindlimb specification. Morphometric analyses of anole fore and hindlimbs corroborated these findings. We detect signatures of positive selection across several genes related to the development and regulation of the forebrain, hormones, and the iguanian lizard dewlap, suggesting molecular changes underlying behavioral adaptations known to reinforce species boundaries were a key component in the diversification of anole lizards. PMID:29360978

Surface disinfection procedure and in vitro regeneration of grapevine (Vitis vinifera L.) axillary buds.

PubMed

Lazo-Javalera, M F; Troncoso-Rojas, R; Tiznado-Hernández, M E; Martínez-Tellez, M A; Vargas-Arispuro, I; Islas-Osuna, M A; Rivera-Domínguez, M

2016-01-01

Establishment of an efficient explants surface disinfection protocol is essential for in vitro cell and tissue culture as well as germplasm conservation, such as the case of Grapevine (Vitis spp.) culture. In this research, different procedures for disinfection and regeneration of field-grown grapevine cv. 'Flame seedless' axillary buds were evaluated. The buds were disinfected using either NaOCl or allyl, benzyl, phenyl and 2-phenylethyl isothiocyanates. Two different media for shooting and four media for rooting were tested. Shoot and root development per buds were registered. The best disinfection procedure with 90 % of tissue survival involved shaking for 60 min in a solution containing 20 % Clorox with 50 drops/L Triton(®) X-100. These tissues showed the potential to regenerate a complete plant. Plant regeneration was conducted using full strength Murashigue and Skoog (MS) medium supplemented with 8 µM benzyl aminopurine for shoot induction and multiplication, whereas rooting was obtained on half strength MS supplemented with 2 mg L(-1) of indole-3-butyric acid and 200 mg L(-1) of activated charcoal. In this work, it was designed the protocols for obtaining sterile field-grown grapevine buds and in vitro plant development. This methodology showed potential to produce vigorous and healthy plants in 5 weeks for clonal grapevine propagation. Regenerated plants were successfully established in soil.

Chilling Affects Phytohormone and Post-Embryonic Development Pathways during Bud Break and Fruit Set in Apple (Malus domestica Borkh.)

PubMed Central

Kumar, Gulshan; Gupta, Khushboo; Pathania, Shivalika; Swarnkar, Mohit Kumar; Rattan, Usha Kumari; Singh, Gagandeep; Sharma, Ram Kumar; Singh, Anil Kumar

2017-01-01

The availability of sufficient chilling during bud dormancy plays an important role in the subsequent yield and quality of apple fruit, whereas, insufficient chilling availability negatively impacts the apple production. The transcriptome profiling during bud dormancy release and initial fruit set under low and high chill conditions was performed using RNA-seq. The comparative high number of differentially expressed genes during bud break and fruit set under high chill condition indicates that chilling availability was associated with transcriptional reorganization. The comparative analysis reveals the differential expression of genes involved in phytohormone metabolism, particularly for Abscisic acid, gibberellic acid, ethylene, auxin and cytokinin. The expression of Dormancy Associated MADS-box, Flowering Locus C-like, Flowering Locus T-like and Terminal Flower 1-like genes was found to be modulated under differential chilling. The co-expression network analysis indentified two high chill specific modules that were found to be enriched for “post-embryonic development” GO terms. The network analysis also identified hub genes including Early flowering 7, RAF10, ZEP4 and F-box, which may be involved in regulating chilling-mediated dormancy release and fruit set. The results of transcriptome and co-expression network analysis indicate that chilling availability majorly regulates phytohormone-related pathways and post-embryonic development during bud break. PMID:28198417

Organogenesis from internode-derived nodules of Humulus lupulus var. Nugget (Cannabinaceae): histological studies and changes in the starch content.

PubMed

Fortes, A M; Pais, M S

2000-07-01

The sequence of histological and histochemical events occurring during organogenesis from Humulus lupulus var. Nugget internode-derived nodules was studied. Sections were made and studies were carried out from the start of culture treatment until the development of shoot buds. Cell division was observed in both cambial and cortical regions during the first week of culture establishment. Cell division in cortical cells led to the formation of an incipient callus tissue. From the calluses prenodular structures of cambial origin appeared and gave rise to nodules from which shoot buds formed. Nodules kept separating into "daughter nodules" from which arose an increasing number of shoot buds. Iodide staining showed a strong starch accumulation in callus tissue and in prenodular structures. During shoot-bud primordia formation starch content decreased in nodules. Some starch was also noted in control explants (cultured on basal medium), however at a lower level than that observed in explants cultured on media with growth regulators. Shoot-bud regeneration was not observed in control explants.

Measurement of the volume growth rate of single budding yeast with the MOSFET-based microfluidic Coulter counter

PubMed Central

Sun, Jiashu; Stowers, Chris C.; Boczko, Erik M.

2012-01-01

We report on measurements of the volume growth rate of ten individual budding yeast cells using a recently developed MOSFET-based microfluidic Coulter counter. The MOSFET-based microfluidic Coulter counter is very sensitive, provides signals that are immune from the baseline drift, and can work with cell culture media of complex composition. These desirable features allow us to directly measure the volume growth rate of single cells of Saccharomyces cerevisiae LYH3865 strain budding yeast in YNB culture media over a whole cell cycle. Results indicate that all budding yeast follow a sigmoid volume growth profile with reduced growth rates at the initial stage before the bud emerges and the final stage after the daughter gets mature. Analysis of the data indicates that even though all piecewise linear, Gomperitz, and Hill’s function models can fit the global growth profile equally well, the data strongly support local exponential growth phenomenon. Accurate volume growth measurements are important for applications in systems biology where quantitative parameters are required for modeling and simulation. PMID:20717618

Measurement of the volume growth rate of single budding yeast with the MOSFET-based microfluidic Coulter counter.

PubMed

Sun, Jiashu; Stowers, Chris C; Boczko, Erik M; Li, Deyu

2010-11-07

We report on measurements of the volume growth rate of ten individual budding yeast cells using a recently developed MOSFET-based microfluidic Coulter counter. The MOSFET-based microfluidic Coulter counter is very sensitive, provides signals that are immune from the baseline drift, and can work with cell culture media of complex composition. These desirable features allow us to directly measure the volume growth rate of single cells of Saccharomyces cerevisiae LYH3865 strain budding yeast in YNB culture media over a whole cell cycle. Results indicate that all budding yeast follow a sigmoid volume growth profile with reduced growth rates at the initial stage before the bud emerges and the final stage after the daughter gets mature. Analysis of the data indicates that even though all piecewise linear, Gomperitz, and Hill's function models can fit the global growth profile equally well, the data strongly support local exponential growth phenomenon. Accurate volume growth measurements are important for applications in systems biology where quantitative parameters are required for modeling and simulation.

Postnatal reduction of BDNF regulates the developmental remodeling of taste bud innervation

PubMed Central

Huang, Tao; Ma, Liqun; Krimm, Robin F

2015-01-01

The refinement of innervation is a common developmental mechanism that serves to increase the specificity of connections following initial innervation. In the peripheral gustatory system, the extent to which innervation is refined and how refinement might be regulated is unclear. The initial innervation of taste buds is controlled by brain-derived neurotrophic factor (BDNF). Following initial innervation, taste receptor cells are added and become newly innervated. The connections between the taste receptor cells and nerve fibers are likely to be specific in order to retain peripheral coding mechanisms. Here, we explored the possibility that the down-regulation of BDNF regulates the refinement of taste bud innervation during postnatal development. An analysis of BDNF expression in BdnflacZ/+ mice and real-time reverse transcription polymerase chain reaction (RT-PCR) revealed that BDNF was down-regulated between postnatal day (P) 5 and P10. This reduction in BDNF expression was due to a loss of precursor/progenitor cells that express BDNF, while the expression of BDNF in the subpopulations of taste receptor cells did not change. Gustatory innervation, which was identified by P2X3 immunohistochemistry, was lost around the perimeter where most progenitor/precursor cells are located. In addition, the density of innervation in the taste bud was reduced between P5 and P10, because taste buds increase in size without increasing innervation. This reduction of innervation density was blocked by the overexpression of BDNF in the precursor/progenitor population of taste bud cells. Together these findings indicate that the process of BDNF restriction to a subpopulation of taste receptor cells between P5 and P10, results in a refinement of gustatory innervation. We speculate that this refinement results in an increased specificity of connections between neurons and taste receptor cells during development. PMID:26164656

Patterns of immunoreactivity specific for gustducin and for NCAM differ in developing rat circumvallate papillae and their taste buds.

PubMed

Iwasaki, Shin-Ichi; Aoyagi, Hidekazu; Asami, Tomoichiro; Wanichanon, Chaitip; Jackowiak, Hanna

2012-05-01

α-Gustducin and neural cell adhesion molecule (NCAM) are molecules previously found to be expressed in different cell types of mammalian taste buds. We examined the expression of α-gustducin and NCAM during the morphogenesis of circumvallate papillae and the formation of their taste buds by immunofluorescence staining and laser-scanning microscopy of semi-ultrathin sections of fetal and juvenile rat tongues. Images obtained by confocal laser scanning microscopy in transmission mode were also examined to provide outlines of histology and cell morphology. Morphogenesis of circumvallate papillae had already started on embryonic day 13 (E13) and was evident as the formation of placode. By contrast, taste buds in the circumvallate papillae started to appear between postnatal day 0 (P0) and P7. Although no cells with immunoreactivity specific for α-gustducin were detected in fetuses from E13 to E19, cells with NCAM-specific immunoreactivity were clearly apparent in the entire epithelium of the circumvallate papillary placode, the rudiment of each circumvallate papilla and the developing circumvallate papilla itself from E13 to E19. However, postnatally, both α-gustducin and NCAM became concentrated within taste cells as the formation of taste buds advanced. After P14, neither NCAM nor α-gustducin was detectable in the epithelium around the taste buds. In conclusion, α-gustducin appeared in the cytoplasm of taste cells during their formation after birth, while NCAM appeared in the epithelium of the circumvallate papilla-forming area. However, these two markers of taste cells were similarly distributed within mature taste cells. Copyright © 2011 Elsevier GmbH. All rights reserved.

Vitamin C-sulfate inhibits mineralization in chondrocyte cultures: a caveat

NASA Technical Reports Server (NTRS)

Boskey, A. L.; Blank, R. D.; Doty, S. B.

2001-01-01

Differentiating chick limb-bud mesenchymal cell micro-mass cultures routinely mineralize in the presence of 10% fetal calf serum, antibiotics, 4 mM inorganic phosphate (or 2.5 mM beta-glycerophosphate), 0.3 mg/ml glutamine and either 25 microg/ml vitamin C or 5-12 microg/ml vitamin C-sulfate. The failure of these cultures to produce a mineralized matrix (assessed by electron microscopy, 45Ca uptake and Fourier transform infrared microscopy) led to the evaluation of each of these additives. We report here that the "stable" vitamin C-sulfate (ascorbic acid-2-sulfate) causes increased sulfate incorporation into the cartilage matrix. Furthermore, the release of sulfate from the vitamin C derivative appears to be responsible for the inhibition of mineral deposition, as demonstrated in cultures with equimolar amounts of vitamin C and sodium sulfate.

Stem cell- and scaffold-based tissue engineering approaches to osteochondral regenerative medicine

PubMed Central

Sundelacruz, Sarah; Kaplan, David L.

2009-01-01

In osteochondral tissue engineering, cell recruitment, proliferation, differentiation, and patterning are critical for forming biologically and structurally viable constructs for repair of damaged or diseased tissue. However, since constructs prepared ex vivo lack the multitude of cues present in the in vivo microenvironment, cells often need to be supplied with external biological and physical stimuli to coax them towards targeted tissue functions. To determine which stimuli to present to cells, bioengineering strategies can benefit significantly from endogenous examples of skeletogenesis. As an example of developmental skeletogenesis, the developing limb bud serves as an excellent model system in which to study how an osteochondral structures form from undifferentiated precursor cells. Alongside skeletal formation during embryogenesis, bone also possesses innate regenerative capacity, displaying remarkable ability to heal after damage. Bone fracture healing shares many features with bone development, driving the hypothesis that the regenerative process generally recapitulates development. Similarities and differences between the two modes of bone formation may offer insight into the special requirements for healing damaged or diseased bone. Thus, endogenous fracture healing, as an example of regenerative skeletogenesis, may also inform bioengineering strategies. In this review, we summarize the key cellular events involving stem and progenitor cells in developmental and regenerative skeletogenesis, and discuss in parallel the corresponding cell- and scaffold-based strategies that tissue engineers employ to recapitulate these events in vitro. PMID:19508851

Progress and renewal in gustation: new insights into taste bud development.

PubMed

Barlow, Linda A

2015-11-01

The sense of taste, or gustation, is mediated by taste buds, which are housed in specialized taste papillae found in a stereotyped pattern on the surface of the tongue. Each bud, regardless of its location, is a collection of ∼100 cells that belong to at least five different functional classes, which transduce sweet, bitter, salt, sour and umami (the taste of glutamate) signals. Taste receptor cells harbor functional similarities to neurons but, like epithelial cells, are rapidly and continuously renewed throughout adult life. Here, I review recent advances in our understanding of how the pattern of taste buds is established in embryos and discuss the cellular and molecular mechanisms governing taste cell turnover. I also highlight how these findings aid our understanding of how and why many cancer therapies result in taste dysfunction. © 2015. Published by The Company of Biologists Ltd.

Fungiform taste bud degeneration in C57BL/6J mice following chorda-lingual nerve transection.

PubMed

Guagliardo, Nick A; Hill, David L

2007-09-10

Taste buds are dependent on innervation for normal morphology and function. Fungiform taste bud degeneration after chorda tympani nerve injury has been well documented in rats, hamsters, and gerbils. The current study examines fungiform taste bud distribution and structure in adult C57BL/6J mice from both intact taste systems and after unilateral chorda-lingual nerve transection. Fungiform taste buds were visualized and measured with the aid of cytokeratin 8. In control mice, taste buds were smaller and more abundant on the anterior tip (<1 mm) of the tongue. By 5 days after nerve transection taste buds were smaller and fewer on the side of the tongue ipsilateral to the transection and continued to decrease in both size and number until 15 days posttransection. Degenerating fungiform taste buds were smaller due to a loss of taste bud cells rather than changes in taste bud morphology. While almost all taste buds disappeared in more posterior fungiform papillae by 15 days posttransection, the anterior tip of the tongue retained nearly half of its taste buds compared to intact mice. Surviving taste buds could not be explained by an apparent innervation from the remaining intact nerves. Contralateral effects of nerve transection were also observed; taste buds were larger due to an increase in the number of taste bud cells. These data are the first to characterize adult mouse fungiform taste buds and subsequent degeneration after unilateral nerve transection. They provide the basis for more mechanistic studies in which genetically engineered mice can be used. (c) 2007 Wiley-Liss, Inc.

Heterogeneity of fish taste bud ultrastructure as demonstrated in the holosteans Amia calva and Lepisosteus oculatus.

PubMed Central

Reutter, K; Boudriot, F; Witt, M

2000-01-01

Taste buds are the peripheral sensory organs of the gustatory system. They occur in all taxa of vertebrates and are pear-shaped intra-epithelial organs of about 80 microm height and 50 microm width. Taste buds mainly consist of specialized epithelial cells, which synapse at their bases and therefore are secondary sensory cells. Taste buds have been described based on studies of teleostean species, but it turned out that the ultrastructure of teleostean taste buds may differ between distinct systematic groups and that this description is not representative of those taste buds in other main taxa of fishes, such as selachians, holosteans and dipnoans. Furthermore, it is not known how variable the micromorphologies of non-teleostean taste buds are. For this reason the taste buds of two holosteans, Lepisosteus oculatus and Amia calva, were investigated and compared. While in both species the taste buds are of the same shapes and sizes, the cellular components of their sensory epithelia differ: in Lepisosteus taste buds comprise two types of elongated light cells and one type of dark cells. In contrast, Amia taste buds contain only one type of light, but two types of dark elongated cells. Afferent synapses are common in the buds of both species, efferent synapses occur only in Lepisosteus taste buds. These differences show that even in the small group of holostean fishes the taste buds are differently organized. Consequently, a representative type of fish taste buds does not exist. PMID:11079403

Heterogeneity of fish taste bud ultrastructure as demonstrated in the holosteans Amia calva and Lepisosteus oculatus.

PubMed

Reutter, K; Boudriot, F; Witt, M

2000-09-29

Taste buds are the peripheral sensory organs of the gustatory system. They occur in all taxa of vertebrates and are pear-shaped intra-epithelial organs of about 80 microm height and 50 microm width. Taste buds mainly consist of specialized epithelial cells, which synapse at their bases and therefore are secondary sensory cells. Taste buds have been described based on studies of teleostean species, but it turned out that the ultrastructure of teleostean taste buds may differ between distinct systematic groups and that this description is not representative of those taste buds in other main taxa of fishes, such as selachians, holosteans and dipnoans. Furthermore, it is not known how variable the micromorphologies of non-teleostean taste buds are. For this reason the taste buds of two holosteans, Lepisosteus oculatus and Amia calva, were investigated and compared. While in both species the taste buds are of the same shapes and sizes, the cellular components of their sensory epithelia differ: in Lepisosteus taste buds comprise two types of elongated light cells and one type of dark cells. In contrast, Amia taste buds contain only one type of light, but two types of dark elongated cells. Afferent synapses are common in the buds of both species, efferent synapses occur only in Lepisosteus taste buds. These differences show that even in the small group of holostean fishes the taste buds are differently organized. Consequently, a representative type of fish taste buds does not exist.

Cell lineage mapping of taste bud cells and keratinocytes in the mouse tongue and soft palate.

PubMed

Okubo, Tadashi; Clark, Cheryl; Hogan, Brigid L M

2009-02-01

The epithelium of the mouse tongue and soft palate consists of at least three distinct epithelial cell populations: basal cells, keratinized cells organized into filiform and fungiform papillae, and taste receptor cells present in tight clusters known as taste buds in the fungiform and circumvallate papillae and soft palate. All three cell types develop from the simple epithelium of the embryonic tongue and palate, and are continually replaced in the adult by cell turnover. Previous studies using pulse-chase tritiated thymidine labeling in the adult mouse provided evidence for a high rate of cell turnover in the keratinocytes (5-7 days) and taste buds (10 days). However, little is known about the localization and phenotype of the long-term stem or progenitor cells that give rise to the mature taste bud cells and surrounding keratinocytes in these gustatory tissues. Here, we make use of a tamoxifen-inducible K14-CreER transgene and the ROSA26 LacZ reporter allele to lineage trace the mature keratinocytes and taste bud cells of the early postnatal and adult mouse tongue and soft palate. Our results support the hypothesis that both the pore keratinocytes and receptor cells of the taste bud are derived from a common K14(+)K5(+)Trp63(+)Sox2(+) population of bipotential progenitor cells located outside the taste bud. The results are also compatible with models in which the keratinocytes of the filiform and fungiform papillae are derived from basal progenitor cells localized at the base of these structures.

Application of microscopy technique and high-performance liquid chromatography for quality assessment of the flower bud of Tussilago farfara L. (Kuandonghua)

PubMed Central

Li, Da; Liang, Li; Zhang, Jing; Kang, Tingguo

2015-01-01

Background: Quality control is one of the bottleneck problems limiting the application and development of traditional Chinese medicine (TCM). In recent years, microscopy and high-performance liquid chromatography (HPLC) techniques have been frequently applied in the quality control of TCM. However, studies combining conventional microscopy and HPLC techniques for the quality control of the flower bud of Tussilago farfara L. (Kuandonghua) have not been reported. Objective: This study was undertaken to evaluate the quality of the flower bud of T. farfara L. and to establish the relationships between the quantity of pollen grains and four main bioactive constituents: tussilagone, chlorogenic acid, rutin and isoquercitrin. Materials and Methods: In this study, microscopic examination was used to quantify microscopic characteristics of the flower bud of T. farfara L., and the chemical components were determined by HPLC. The data were analyzed by Statistical Package for the Social Sciences statistics software. Results: The results of the analysis showed that tussilagone, chlorogenic acid, rutin and isoquercitrin were significantly correlated with the quantity of pollen grains in the flower bud of T. farfara L. There is a positive correlation between them. From these results, it can be deduced that the flower bud of T. farfara L. with a greater quantity of pollen grains should be of better quality. Conclusion: The study showed that the established method can be helpful for evaluating the quality of the flower bud of T. farfara L. based on microscopic characteristic constants and chemical quantitation. PMID:26246737

Quantitative analysis of taste bud cell numbers in fungiform and soft palate taste buds of mice.

PubMed

Ohtubo, Yoshitaka; Yoshii, Kiyonori

2011-01-07

Mammalian taste bud cells (TBCs) consist of several cell types equipped with different taste receptor molecules, and hence the ratio of cell types in a taste bud constitutes the taste responses of the taste bud. Here we show that the population of immunohistochemically identified cell types per taste bud is proportional to the number of total TBCs in the taste bud or the area of the taste bud in fungiform papillae, and that the proportions differ among cell types. This result is applicable to soft palate taste buds. However, the density of almost all cell types, the population of cell types divided by the area of the respective taste buds, is significantly higher in soft palates. These results suggest that the turnover of TBCs is regulated to keep the ratio of each cell type constant, and that taste responsiveness is different between fungiform and soft palate taste buds. Copyright © 2010 Elsevier B.V. All rights reserved.

[Impact of TDZ and NAA on adventitious bud induction and cluster bud multiplication in Tulipa edulis].

PubMed

Zhu, Li-Fang; Xu, Chao; Zhu, Zai-Biao; Yang, He-Tong; Guo, Qiao-Sheng; Xu, Hong-jian; Ma, Hong-Jian; Zhao, Gui-Hua

2014-08-01

To explore the method of explants directly induced bud and establish the tissue culture system of mutiple shoot by means of direct organogenesis, core bud and daughter bulbs (the top of bud stem expanded to form daughter bulb) of T. edulis were used as explants and treated with thidiazuron (TDZ) and 1-naphthlcetic acid (NAA). The results showed that the optimal medium for bud inducted form core bud and daughter bulb were MS + TDZ 2.0 mg x L(-1) + NAA 4.0 mg x L(-1) and MS +TDZ 2.0 mg x L(-1) + NAA 2.0 mg x L(-1) respectively, both of them had a bud induction rate of 72.92%, 79.22%. The optimal medium for cluster buds multiplication was MS + TDZ 0.2 mg x L(-1) + NAA 0.2 mg x L(-1), and proliferation coefficient was 2.23. After proliferation, cluster buds rooting occurred on MS medium with IBA 1.0 mg x L(-1) and the rooting rate was 52.6%, three to five seedlings in each plant. Using core bud and daughter bulb of T. edulis, the optimum medium for adventitious bud directly inducted from daughter bulb, core bud and cluster bud multiplication were screened out and the tissue culture system of multiple shoot by means of direct organogenesis was established.

Fetus in fetu: two case reports and literature review

PubMed Central

2014-01-01

Background Fetus in fetu is a rare congenital anomaly and is defined as a monozygotic twin incorporated into the abdomen of its sibling during development. Fetus in fetu is often overlooked in the differential diagnosis of an abdominal mass. Unlike teratomas, fetus in fetu is a benign disorder. Case presentation We describe the clinical characteristics of two patients, a thirty-months old boy who was found to have abdominal distension and a neonate who was diagnosed antenatally with abdominal mass. Computed tomography scan revealed the mass in which the contents favor a fetus in fetu rather than a teratoma. Surgical removal revealed that the anencephalic fetus have limb buds situated relative to a palpable vertebral column, supporting the diagnosis of fetus in fetu. In the present report, presentation, diagnosis, pathology, management, and recent literature are also reviewed. Conclusion Fetus in fetu is a rare entity that typically presents in infancy and early childhood. It should be differentiated from a teratoma because of the teratoma’s malignant potential. Preoperative diagnosis is based on radiologic findings. The treatment of fetus in fetu is operative to relieve obstruction, prevent further compression and possible complications. Complete excision allows confirmation of the diagnosis and lowers the risk of recurrence. PMID:24693883

Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) Pathway Is Induced by Mechanical Load and Reduces the Activity of Hedgehog Signaling in Chondrogenic Micromass Cell Cultures

PubMed Central

Juhász, Tamás; Szentléleky, Eszter; Szűcs Somogyi, Csilla; Takács, Roland; Dobrosi, Nóra; Engler, Máté; Tamás, Andrea; Reglődi, Dóra; Zákány, Róza

2015-01-01

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurohormone exerting protective function during various stress conditions either in mature or developing tissues. Previously we proved the presence of PACAP signaling elements in chicken limb bud-derived chondrogenic cells in micromass cell cultures. Since no data can be found if PACAP signaling is playing any role during mechanical stress in any tissues, we aimed to investigate its contribution in mechanotransduction during chondrogenesis. Expressions of the mRNAs of PACAP and its major receptor, PAC1 increased, while that of other receptors, VPAC1, VPAC2 decreased upon mechanical stimulus. Mechanical load enhanced the expression of collagen type X, a marker of hypertrophic differentiation of chondrocytes and PACAP addition attenuated this elevation. Moreover, exogenous PACAP also prevented the mechanical load evoked activation of hedgehog signaling: protein levels of Sonic and Indian Hedgehogs and Gli1 transcription factor were lowered while expressions of Gli2 and Gli3 were elevated by PACAP application during mechanical load. Our results suggest that mechanical load activates PACAP signaling and exogenous PACAP acts against the hypertrophy inducing effect of mechanical load. PMID:26230691

Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) Pathway Is Induced by Mechanical Load and Reduces the Activity of Hedgehog Signaling in Chondrogenic Micromass Cell Cultures.

PubMed

Juhász, Tamás; Szentléleky, Eszter; Somogyi, Csilla Szűcs; Takács, Roland; Dobrosi, Nóra; Engler, Máté; Tamás, Andrea; Reglődi, Dóra; Zákány, Róza

2015-07-29

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurohormone exerting protective function during various stress conditions either in mature or developing tissues. Previously we proved the presence of PACAP signaling elements in chicken limb bud-derived chondrogenic cells in micromass cell cultures. Since no data can be found if PACAP signaling is playing any role during mechanical stress in any tissues, we aimed to investigate its contribution in mechanotransduction during chondrogenesis. Expressions of the mRNAs of PACAP and its major receptor, PAC1 increased, while that of other receptors, VPAC1, VPAC2 decreased upon mechanical stimulus. Mechanical load enhanced the expression of collagen type X, a marker of hypertrophic differentiation of chondrocytes and PACAP addition attenuated this elevation. Moreover, exogenous PACAP also prevented the mechanical load evoked activation of hedgehog signaling: protein levels of Sonic and Indian Hedgehogs and Gli1 transcription factor were lowered while expressions of Gli2 and Gli3 were elevated by PACAP application during mechanical load. Our results suggest that mechanical load activates PACAP signaling and exogenous PACAP acts against the hypertrophy inducing effect of mechanical load.

Functional autonomy of distant-acting human enhancers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Visel, Axel; Akiyama, Jennifer A.; Shoukry, Malak

2009-02-19

Many human genes are associated with dispersed arrays of transcriptional enhancers that regulate their expression in time and space. Studies in invertebrate model systems have suggested that these elements function as discrete and independent regulatory units, but the in vivo combinatorial properties of vertebrate enhancers remain poorly understood. To explore the modularity and regulatory autonomy of human developmental enhancers, we experimentally concatenated up to four enhancers from different genes and used a transgenic mouse assay to compare the in vivo activity of these compound elements with that of the single modules. In all of the six different combinations of elementsmore » tested, the reporter gene activity patterns were additive without signs of interference between the individual modules, indicating that regulatory specificity was maintained despite the presence of closely-positioned heterologous enhancers. Even in cases where two elements drove expression in close anatomical proximity, such as within neighboring subregions of the developing limb bud, the compound patterns did not show signs of cross-inhibition between individual elements or novel expression sites. These data indicate that human developmental enhancers are highly modular and functionally autonomous and suggest that genomic enhancer shuffling may have contributed to the evolution of complex gene expression patterns in vertebrates« less

Vitrification, a complementary cryopreservation method for Betula pendula Roth.

PubMed

Ryynänen, Leena; Aronen, Tuija

2005-10-01

Cryopreservation--the storage of plant germplasm in liquid nitrogen--provides a modern tool for the conservation of forest genetic resources. It is especially applicable for species in which their micropropagation can be initiated from mature tree buds, e.g., silver birch (Betula pendula Roth), thus enabling the conservation of specific genotypes: endangered elite trees and trees expressing rare, valuable or interesting characteristics. The aim of the present study was to develop a vitrification protocol applicable for the cryostorage of silver birch that avoids the use of expensive sophisticated freezers. The average recovery of vitrified axillary silver birch buds was 71% using a protocol that started with four-week cold hardening of bud-bearing in vitro donor shoots on modified medium under short day conditions. After cold hardening, the excised axillary buds were precultivated on medium containing 0.7 M sucrose for 24 h under the same conditions as during the cold hardening period. Following preculture, the buds were treated with loading solution containing 2M glycerol and 0.4 M sucrose for 20 min at room temperature. Finally, the buds were dehydrated with PVS2 cryoprotectant for 120 min followed by direct immersion in liquid nitrogen. According to the morphology and the RAPD profiles of regenerated plants in the greenhouse, the genetic fidelity of the vitrified birch material seems to have remained unchanged.

Discrete innervation of murine taste buds by peripheral taste neurons.

PubMed

Zaidi, Faisal N; Whitehead, Mark C

2006-08-09

The peripheral taste system likely maintains a specific relationship between ganglion cells that signal a particular taste quality and taste bud cells responsive to that quality. We have explored a measure of the receptoneural relationship in the mouse. By injecting single fungiform taste buds with lipophilic retrograde neuroanatomical markers, the number of labeled geniculate ganglion cells innervating single buds on the tongue were identified. We found that three to five ganglion cells innervate a single bud. Injecting neighboring buds with different color markers showed that the buds are primarily innervated by separate populations of geniculate cells (i.e., multiply labeled ganglion cells are rare). In other words, each taste bud is innervated by a population of neurons that only connects with that bud. Palate bud injections revealed a similar, relatively exclusive receptoneural relationship. Injecting buds in different regions of the tongue did not reveal a topographic representation of buds in the geniculate ganglion, despite a stereotyped patterned arrangement of fungiform buds as rows and columns on the tongue. However, ganglion cells innervating the tongue and palate were differentially concentrated in lateral and rostral regions of the ganglion, respectively. The principal finding that small groups of ganglion cells send sensory fibers that converge selectively on a single bud is a new-found measure of specific matching between the two principal cellular elements of the mouse peripheral taste system. Repetition of the experiments in the hamster showed a more divergent innervation of buds in this species. The results indicate that whatever taste quality is signaled by a murine geniculate ganglion neuron, that signal reflects the activity of cells in a single taste bud.

A review of supernumerary and absent limbs and digits of the upper limb.

PubMed

Klaassen, Zachary; Choi, Monica; Musselman, Ruth; Eapen, Deborah; Tubbs, R Shane; Loukas, Marios

2012-03-01

For years people have been enamored by anomalies of the human limbs, particularly supernumerary and absent limbs and digits. Historically, there are a number of examples of such anomalies, including royal families of ancient Chaldea, tribes from Arabia, and examples from across nineteenth century Europe. The development of the upper limbs in a growing embryo is still being elucidated with the recent advent of homeobox genes, but researchers agree that upper limbs develop between stages 12-23 through a complex embryological process. Maternal thalidomide intake during limb development is known to cause limb reduction and subsequent amelia or phocomelia. Additionally, a number of clinical reports have illustrated different limb anomaly cases, with each situation unique in phenotype and developmental abnormality. Supernumerary and absent limbs and digits are not unique to humans, and a number of animal cases have also been reported. This review of the literature illustrates the historical, anatomical, and clinical aspects of supernumerary and absent limbs and digits for the upper limb.

Assessment of regeneration potential in the clonal macrophyte Miscanthus sacchariflorus (Poaceae) after burial disturbance based on bud bank size and sprouting capacity.

PubMed

Chen, Xinsheng; Cao, Chenshu; Deng, Zhengmiao; Xie, Yonghong; Li, Feng; Hou, Zhiyong; Li, Xu

2015-01-01

The demography of the bud bank and its sprouting capacity are important for understanding the population dynamics of clonal plants and their potential responses to disturbances. To this end, we investigated the size and composition of the bud bank of Miscanthus sacchariflorus (Maxim.) Hack. immediately after flooding (November), in winter (January), in spring (March), and before flooding (May) in the wetlands of Dongting Lake. We then examined the sprouting capacity of axillary buds after sediment burial at 0, 5, 10, 15, and 20 cm. Total bud density of M. sacchariflorus ranged from 2524 buds m(-2) in November to 4293 buds m(-2) in March. Rhizome segments with inactive axillary buds, which represented the majority of the bud population (88.7% in November, 93.3% in May), did not sprout during the 140 days of the experiment (n = 250). The sprouting ratio was the highest for active axillary buds buried at 0 cm (64%) and decreased when buried at 10-20 cm (34%-40%). Due to the large number of active axillary buds in the bud bank (211-277 buds m(-2) from November to the following March), M. sacchariflorus could completely replace its aboveground shoot population, except in May (142 buds m(-2)). Increasing burial depth delayed bud emergence and reduced the growth period of shoots; however, burial depth did not affect the resulting plant height and only reduced the accumulated biomass at 20 cm. Therefore, the belowground bud bank and its strong sprouting capacity are important factors in the maintenance of local populations and colonization of new habitats for M. sacchariflorus after burial disturbances. The present methodology, which combined measurements of bud bank demography and sprouting capacity, may reflect the regeneration potential of clonal plants after burial disturbances.

In vivo imaging of basement membrane movement: ECM patterning shapes Hydra polyps

PubMed Central

Aufschnaiter, Roland; Zamir, Evan A.; Little, Charles D.; Özbek, Suat; Münder, Sandra; David, Charles N.; Li, Li; Sarras, Michael P.; Zhang, Xiaoming

2011-01-01

Growth and morphogenesis during embryonic development, asexual reproduction and regeneration require extensive remodeling of the extracellular matrix (ECM). We used the simple metazoan Hydra to examine the fate of ECM during tissue morphogenesis and asexual budding. In growing Hydra, epithelial cells constantly move towards the extremities of the animal and into outgrowing buds. It is not known, whether these tissue movements involve epithelial migration relative to the underlying matrix or whether cells and ECM are displaced as a composite structure. Furthermore, it is unclear, how the ECM is remodeled to adapt to the shape of developing buds and tentacles. To address these questions, we used a new in vivo labeling technique for Hydra collagen-1 and laminin, and tracked the fate of ECM in all body regions of the animal. Our results reveal that Hydra ‘tissue movements’ are largely displacements of epithelial cells together with associated ECM. By contrast, during the evagination of buds and tentacles, extensive movement of epithelial cells relative to the matrix is observed, together with local ECM remodeling. These findings provide new insights into the nature of growth and morphogenesis in epithelial tissues. PMID:22194305

Transcriptome analysis of Jatropha curcas L. flower buds responded to the paclobutrazol treatment.

PubMed

Seesangboon, Anupharb; Gruneck, Lucsame; Pokawattana, Tittinat; Eungwanichayapant, Prapassorn Damrongkool; Tovaranonte, Jantrararuk; Popluechai, Siam

2018-06-01

Jatropha seeds can be used to produce high-quality biodiesel due to their high oil content. However, Jatropha produces low numbers of female flowers, which limits seed yield. Paclobutrazol (PCB), a plant growth retardant, can increase number of Jatropha female flowers and seed yield. However, the underlying mechanisms of flower development after PCB treatment are not well understood. To identify the critical genes associated with flower development, the transcriptome of flower buds following PCB treatment was analyzed. Scanning Electron Microscope (SEM) analysis revealed that the flower developmental stage between PCB-treated and control flower buds was similar. Based on the presence of sex organs, flower buds at 0, 4, and 24 h after treatment were chosen for global transcriptome analysis. In total, 100,597 unigenes were obtained, 174 of which were deemed as interesting based on their response to PCB treatment. Our analysis showed that the JcCKX5 and JcTSO1 genes were up-regulated at 4 h, suggesting roles in promoting organogenic capacity and ovule primordia formation in Jatropha. The JcNPGR2, JcMGP2-3, and JcHUA1 genes were down-regulated indicating that they may contribute to increased number of female flowers and amount of seed yield. Expression of cell division and cellulose biosynthesis-related genes, including JcGASA3, JcCycB3;1, JcCycP2;1, JcKNAT7, and JcCSLG3 was decreased, which might have caused the compacted inflorescences. This study represents the first report combining SEM-based morphology, qRT-PCR and transcriptome analysis of PCB-treated Jatropha flower buds at different stages of flower development. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Multiple shoot induction from axillary bud cultures of the medicinal orchid, Dendrobium longicornu

PubMed Central

Dohling, Stadwelson; Kumaria, Suman; Tandon, Pramod

2012-01-01

Background and aims Dendrobium longicornu, commonly known as the ‘Long-horned Dendrobium’, is an endangered and medicinally important epiphytic orchid. Over-exploitation and habitat destruction seriously threaten this orchid in Northeast India. Our objective was to develop an efficient protocol for the mass propagation of D. longicornu using axillary bud segments. Methodology and principal results Axillary buds cultured in Murashige and Skoog semi-solid medium supplemented with α-naphthalene acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D) and 6-benzylaminopurine (BAP) readily developed into plantlets. These formed either directly from shoot buds or from intermediary protocorm-like bodies (PLBs). The maximum explant response (86.6 %) was obtained in medium supplemented with NAA at 30 µM, while the maximum number of shoots (4.42) and maximum bud-forming capacity (3.51) were observed in medium containing 15 µM BAP and 5 µM NAA in combination. Protocorm-like bodies were obtained when the medium contained 2,4-D. The maximum number of explants forming PLBs (41.48 %) was obtained in medium containing 15 µM BAP and 15 µM 2,4-D. Well-developed plantlets obtained after 20–25 weeks of culture were acclimatized and eventually transferred to the greenhouse. Over 60 % of these survived to form plants ∼3–4 cm tall after 90 days in glasshouse conditions using a substrate of crushed brick and charcoal, shredded bark and moss. Conclusions The method described can readily be used for the rapid and large-scale regeneration of D. longicornu. Its commercial adoption would reduce the collection of this medicinally important and increasingly rare orchid from the wild. PMID:23136638

Patterning by heritage in mouse molar row development.

PubMed

Prochazka, Jan; Pantalacci, Sophie; Churava, Svatava; Rothova, Michaela; Lambert, Anne; Lesot, Hervé; Klein, Ophir; Peterka, Miroslav; Laudet, Vincent; Peterkova, Renata

2010-08-31

It is known from paleontology studies that two premolars have been lost during mouse evolution. During mouse mandible development, two bud-like structures transiently form that may represent rudimentary precursors of the lost premolars. However, the interpretation of these structures and their significance for mouse molar development are highly controversial because of a lack of molecular data. Here, we searched for typical tooth signaling centers in these two bud-like structures, and followed their fate using molecular markers, 3D reconstructions, and lineage tracing in vitro. Transient signaling centers were indeed found to be located at the tips of both the anterior and posterior rudimentary buds. These centers expressed a similar set of molecular markers as the "primary enamel knot" (pEK), the signaling center of the first molar (M1). These two transient signaling centers were sequentially patterned before and anterior to the M1 pEK. We also determined the dynamics of the M1 pEK, which, slightly later during development, spread up to the field formerly occupied by the posterior transient signaling center. It can be concluded that two rudimentary tooth buds initiate the sequential development of the mouse molars and these have previously been mistaken for early stages of M1 development. Although neither rudiment progresses to form an adult tooth, the posterior one merges with the adjacent M1, which may explain the anterior enlargement of the M1 during mouse family evolution. This study highlights how rudiments of lost structures can stay integrated and participate in morphogenesis of functional organs and help in understanding their evolution, as Darwin suspected long ago.

Association of DSM-5 Betel-Quid Use Disorder With Oral Potentially Malignant Disorder in 6 Betel-Quid Endemic Asian Populations.

PubMed

Lee, Chien-Hung; Ko, Albert Min-Shan; Yang, Frances M; Hung, Chung-Chieh; Warnakulasuriya, Saman; Ibrahim, Salah Osman; Zain, Rosnah Binti; Ko, Ying-Chin

2018-03-01

Betel-quid (BQ) is the fourth most popular psychoactive agent worldwide. An emerging trend across Asia is the addictive consumption of BQ, which is associated with oral cancer and other health consequences. To investigate the validity and pattern of DSM-5-defined BQ use disorder (BUD) and its association with oral potentially malignant disorder (OPMD) among Asian populations. In-person interviews were conducted from January 1, 2009, to February 28, 2010, among a random sample of 8922 noninstitutionalized adults from the Asian Betel-quid Consortium study, an Asian representative survey of 6 BQ-endemic populations. Statistical analysis was performed from January 1, 2015, to December 31, 2016. Participants were evaluated for BUD using DSM-5 criteria for substance use disorder and for OPMD using a clinical oral examination. Current users of BQ with 0 to 1 symptoms were classified as having no BUD, those with 2 to 3 symptoms as having mild BUD, those with 4 to 5 symptoms as having moderate BUD, and those with 6 or more symptoms as having severe BUD. Among the 8922 participants (4564 women and 4358 men; mean [SD] age, 44.2 [0.2] years), DSM-5 symptoms showed sufficient unidimensionality to act as a valid measure for BUD. The 12-month prevalence of DSM-5-defined BUD in the 6 study populations was 18.0% (mild BUD, 3.2%; moderate BUD, 4.3%; and severe BUD, 10.5%). The 12-month proportion of DSM-5-defined BUD among current users of BQ was 86.0% (mild BUD, 15.5%; moderate BUD, 20.6%; and severe BUD, 50.0%). Sex, age, low educational level, smoking, and drinking were significantly associated with BUD. Among individuals who used BQ, family use, high frequency of use, and amount of BQ used were significantly linked to moderate to severe BUD. Compared with individuals who did not use BQ, those who used BQ and had no BUD showed a 22.0-fold (95% CI, 4.3-112.4) risk of OPMD (P < .001), whereas those with mild BUD showed a 9.6-fold (95% CI, 1.8-56.8) risk (P = .01), those with moderate BUD showed a 35.5-fold (95% CI, 4.3-292.3) risk (P = .001), and those with severe BUD showed a 27.5-fold (95% CI, 1.6-461.4) risk of OPMD (P = .02). Individuals with moderate to severe BUD who used BQ and had the symptom of tolerance had a 153.4-fold (95% CI, 33.4-703.6) higher risk of OPMD than those who did not use BQ, and those with moderate to severe BUD who used BQ and had a larger amount or longer history of BQ use had an 88.9-fold (95% CI, 16.6-476.5) higher risk of OPMD than those who did not use BQ. This international study gathered data about BQ users across 6 Asian populations, and it demonstrates that DSM-5 symptoms could fulfill a BUD construct. Most current Asian users of BQ already have BUD, which is correlated with risk of OPMD. Among individuals with moderate to severe BUD who used BQ, tolerance and a larger amount or longer history of BQ use are the key symptoms that correlated with enhanced risk of OPMD. These findings play an important role in providing a new indication of an additional psychiatric management plan for users of BQ who have BUD.

Effects of early intraoral acesulfame-K stimulation to mice on the adult's sweet preference and the expression of α-gustducin in fungiform papilla.

PubMed

Chen, Meng-Ling; Liu, Si-Si; Zhang, Gen-Hua; Quan, Ying; Zhan, Yue-Hua; Gu, Tian-Yuan; Qin, Yu-Mei; Deng, Shao-Ping

2013-06-01

Exposure to artificial sweetener acesulfame-K (AK) at early development stages may influence the adult sweet preference and the periphery gustatory system. We observed that the intraoral AK stimulation to mice from postnatal day 4 (P4) to weaning decreased the preference thresholds for AK and sucrose solutions in adulthood, with the preference pattern unchanged. The preference scores were increased in the exposure group significantly when compared with the control group at a range of concentrations for AK or sucrose solution. Meanwhile, more α-Gustducin-labeled fungiform taste buds and cells in a single taste bud were induced from week 7 by the early intraoral AK stimulation. However, the growth in the number of α-Gustducin-positive taste bud or positive cell number per taste bud occurred only in the anterior region, the rostral 1-mm part, but not in the intermediate region, the caudal 4-mm part, of the anterior two-third of the tongue containing fungiform papillae. This work extends our previous observations and provides new information about the developmental and regional expression pattern of α-Gustducin in mouse fungiform taste bud under early AK-stimulated conditions.

Pharmacognostic Specification, Chlorogenic Acid Content, and In vitro Antioxidant Activities of Lonicera japonica Flowering Bud.

PubMed

Chaowuttikul, Chayanon; Palanuvej, Chanida; Ruangrungsi, Nijsiri

2017-01-01

Lonicera japonica Thunb. or Japanese Honeysuckle has been widely used in traditional medicine for antipyretic. To establish the pharmacognostic specification of L. japonica flowering bud in Thailand and to determine its chlorogenic acid content and in vitro antioxidant activities. Dried L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were investigated for pharmacognostic specification. Their chlorogenic acid contents were quantitatively analyzed by thin layer chromatography (TLC) densitometry with winCATS software. The mobile phase for TLC development consisted of ethyl acetate: formic acid: acetic acid: water (10:1.1:1.1:2.6). Antioxidant activities were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power assay, nitric oxide scavenging assay, and β-carotene bleaching assays. Qualified L. japonica flowering bud in Thailand was presented that the contents of loss on drying, total ash, acid-insoluble ash, and water should not be >10.11%, 6.59%, 1.14%, and 10.82% by weight, respectively. The ethanol and water soluble extractive values should not be < 16.46% and 28.88% by weight, respectively. Chlorogenic acid content in L. japonica flowering bud was found to be 2.24 ± 0.50 g/100 g of crude drug. L. japonica flowering bud showed DPPH and nitric oxide scavenging activities as well as reducing power property. This pharmacognostic specification with special reference to the chlorogenic acid content can be used for quality control of L. japonica flowering bud in Thailand. The potential antioxidant of this crude drug was demonstrated in vitro . Pharmacognostic specification of Lonicera japonica flowering bud in Thailand has been establishedThe chlorogenic acid content has been quantified by thin layer chromatography-densitometryThe ethanolic extract of L. japonica flowering bud showed antioxidation potential, especially on reducing power property. Abbreviations Used: TLC: Thin layer chromatography, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FRAP: Ferric ion Reducing Antioxidant Power, WHO: World Health Organization, ICH: International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; LOD: Limit of detection; LOQ: Limit of quantitation; BHT: Butylated hydroxytoluene; FeSO 4 : Iron(II) sulfate; DMSO: Dimethyl sulfoxide; TPTZ: 2,4,6-tripyridyl-s-triazine.

Project BudBurst - Meeting the Needs of Climate Change Educators and Scientists

NASA Astrophysics Data System (ADS)

Henderson, S.

2015-12-01

It is challenging for many to get a sense of what climate change means as long periods of time are involved - like decades - which can be difficult to grasp. However, there are a number of citizen science based projects, including NEON's Project BudBurst, that provide the opportunity for both learning about climate change and advancing scientific knowledge. In this presentation, we will share lessons learned from Project BudBurst. Project BudBurst is a national citizen science initiative designed to engage the public in observations of phenological (plant life cycle) events and to increase climate literacy. Project BudBurst is important from an educational perspective, but also because it enables scientists to broaden the geographic and temporal scale of their observations. The goals of Project BudBurst are to 1) increase awareness of phenology as an area of scientific study; 2) Increase awareness of the impacts of changing climates on plants at a continental-scale; and 3) increase science literacy by engaging participants in the scientific process. It was important to better understand if and how Project BudBurst is meeting its goals. Specifically, does participation by non-experts advance scientific knowledge? Does participation advance educational goals and outcomes? Is participation an effective approach to advance/enhance science education in both formal and informal settings? Critical examination of Project BudBurst supports advancement of scientific knowledge and realization of educational objectives. Citizen science collected observations and measurements are being used by scientists as evidenced by the increase of such data in scientific publication. In addition, we found that there is a significant increase in educators utilizing citizen science as part of their instruction. Part of this increase is due to the resources and professional development materials available to educators. Working with partners also demonstrated that the needs of both science and education are being met. Project BudBurst, partners with the PhenoCam Network, National Geographic Society, US Fish and Wildlife Service, National Park Service botanic gardens, science centers and other organizations with both a scientific and educational mission.

Cytokinin is required for escape but not release from auxin mediated apical dominance

PubMed Central

Müller, Dörte; Waldie, Tanya; Miyawaki, Kaori; To, Jennifer PC; Melnyk, Charles W; Kieber, Joseph J; Kakimoto, Tatsuo; Leyser, Ottoline

2015-01-01

Auxin produced by an active primary shoot apex is transported down the main stem and inhibits the growth of the axillary buds below it, contributing to apical dominance. Here we use Arabidopsis thaliana cytokinin (CK) biosynthetic and signalling mutants to probe the role of CK in this process. It is well established that bud outgrowth is promoted by CK, and that CK synthesis is inhibited by auxin, leading to the hypothesis that release from apical dominance relies on an increased supply of CK to buds. Our data confirm that decapitation induces the expression of at least one ISOPENTENYLTRANSFERASE (IPT) CK biosynthetic gene in the stem. We further show that transcript abundance of a clade of the CK-responsive type-A Arabidopsis response regulator (ARR) genes increases in buds following CK supply, and that, contrary to their typical action as inhibitors of CK signalling, these genes are required for CK-mediated bud activation. However, analysis of the relevant arr and ipt multiple mutants demonstrates that defects in bud CK response do not affect auxin-mediated bud inhibition, and increased IPT transcript levels are not needed for bud release following decapitation. Instead, our data suggest that CK acts to overcome auxin-mediated bud inhibition, allowing buds to escape apical dominance under favourable conditions, such as high nitrate availability. Significance Statement It has been proposed that the release of buds from auxin-mediated apical dominance following decapitation requires increased cytokinin biosynthesis and consequent increases in cytokinin supply to buds. Here we show that in Arabidopsis, increases in cytokinin appear to be unnecessary for the release of buds from apical dominance, but rather allow buds to escape the inhibitory effect of apical auxin, thereby promoting bud activation in favourable growth conditions. PMID:25904120

Twig pre-harvest temperature significantly influences effective cryopreservation of Vaccinium dormant buds.

PubMed

Jenderek, Maria M; Tanner, Justin D; Ambruzs, Barbara D; West, Mark; Postman, Joseph D; Hummer, Kim E

2017-02-01

Cryopreservation of temperate woody-plant material by dormant buds is less expensive than using shoot tips isolated from tissue cultured plants; however currently, dormant buds are used only for preservation of selected temperate tree and shrub species. Using dormant buds could be an efficient strategy for long-term preservation of blueberry (Vaccinium L.) genetic resources. In this study, viability of V. hybrid 'Northsky' (PI 554943) dormant buds was evaluated at 30 harvest dates over three consecutive fall/winter seasons to determine the optimal harvest time that promotes high post cryopreservation viability. Twigs with dormant buds were cut into 70 mm segments containing at least two nodes, desiccated, slowly cooled, stored in liquid nitrogen vapor and tested for post-cryopreservation regrowth. The highest regrowth of cryopreserved dormant buds was observed for buds harvested in mid-December and during the first half of January. Pearson's correlation coefficients were computed to evaluate the association between bud characteristics and viability at harvest date and logistic regression models were fit to test the ability of twig characteristics and temperatures to predict post cryopreservation bud viability. Post-cryopreservation viability was negatively correlated (p < 0.05) with average minimum, maximum and daily mean temperature preceding the bud harvest but was not correlated with the dormant bud initial and end moisture content, twig diameter, the number of dormant buds/cm of twig length and the number of days in desiccation. Regression tree analysis suggested post-cryopreservation viability to be between 52 and 80% for dormant buds harvested after a 10 day average maximum air temperature of <11.2 °C. Pre-harvest air temperature was a significant indicator of optimal dormant bud harvest time to produce adequate viability for long term preservation of blueberry genetic resources. Published by Elsevier Inc.

Distribution of α-Gustducin and Vimentin in premature and mature taste buds in chickens.

PubMed

Venkatesan, Nandakumar; Rajapaksha, Prasangi; Payne, Jason; Goodfellow, Forrest; Wang, Zhonghou; Kawabata, Fuminori; Tabata, Shoji; Stice, Steven; Beckstead, Robert; Liu, Hong-Xiang

2016-10-14

The sensory organs for taste in chickens (Gallus sp.) are taste buds in the oral epithelium of the palate, base of the oral cavity, and posterior tongue. Although there is not a pan-taste cell marker that labels all chicken taste bud cells, α-Gustducin and Vimentin each label a subpopulation of taste bud cells. In the present study, we used both α-Gustducin and Vimentin to further characterize chicken taste buds at the embryonic and post-hatching stages (E17-P5). We found that both α-Gustducin and Vimentin label distinct and overlapping populations of, but not all, taste bud cells. A-Gustducin immunosignals were observed as early as E18 and were consistently distributed in early and mature taste buds in embryos and hatchlings. Vimentin immunoreactivity was initially sparse at the embryonic stages then became apparent in taste buds after hatch. In hatchlings, α-Gustducin and Vimentin immunosignals largely co-localized in taste buds. A small subset of taste bud cells were labeled by either α-Gustducin or Vimentin or were not labeled. Importantly, each of the markers was observed in all of the examined taste buds. Our data suggest that the early onset of α-Gustducin in taste buds might be important for enabling chickens to respond to taste stimuli immediately after hatch and that distinctive population of taste bud cells that are labeled by different molecular markers might represent different cell types or different phases of taste bud cells. Additionally, α-Gustducin and Vimentin can potentially be used as molecular markers of all chicken taste buds in whole mount tissue. Copyright © 2016 Elsevier Inc. All rights reserved.

Quantitative anatomical study of taste buds in fungiform papillae of young and old Fischer rats.

PubMed

Mistretta, C M; Oakley, I A

1986-05-01

To determine if differences in neural taste responses relate to taste bud loss in old age, taste buds were counted in fungiform papillae of Fischer 344 rats aged 4 to 6 months, 20 to 24 months, and 30 to 37 months. Papillae anterior to the intermolar eminence on one half of the tongue were examined in serial sections. Presence or absence of a taste bud was noted and taste bud diameter was measured. Average percentages of papillae that contained a taste bud in the three groups were 99.6, 99.3, and 94.7%. This is a significant age-related difference but actual number of taste buds lost in the oldest rats was small. Taste bud diameter did not differ with age and general anatomical characteristics of buds were similar in all groups. Thus, anatomical observations on taste bud maintenance in rats over a wide age range, coupled with neurophysiological data, demonstrate that the integrity of the peripheral gustatory system is not altered greatly in old age.

[Seasonal dynamics and vertical distribution pattern of bud bank in different erosion environments on hilly-gully Loess Plateau of Northwest China].

PubMed

Du, Hua-Dong; Jiao, Ju-Ying; Kou, Meng; Wang, Ning

2013-05-01

This paper studied the vegetation composition, bud composition, and the seasonal dynamics and vertical distribution pattern of bud bank in five erosion environments (sunny gully slope, sunny hilly slope, hilltop, shady hilly slope, and shady gully slope) on the hilly-gully Loess Plateau of North Shaanxi. In the study area, the perennial species with perennial bud bank accounted for 80.3% of the total species, while the annual species with seasonal bud bank took up 19.7% of the total. In vegetation turning-green season, there was a relatively large perennial bud bank stock on the sunny hilly-gully slope where serious erosion occurred, while seasonal bud bank showed a higher bud bank density in blossom and fruit-setting season on the hilltop and two shady slopes where soil erosion intensity was relatively gentle. The proportion of underground bud bank to total perennial bud bank in different erosion environments was relatively stable. On the land surface, the perennial bud bank stock was larger on the sunny slope where the soil disturbance often occurred, whereas the seasonal bud bank stock was larger on the shady slope and hilltop. Due to the different species composition of plant communities in different erosion environments, in addition to the disturbance of soil erosion and the seasonal plant regeneration, the seasonal dynamics and vertical distribution pattern of bud bank changed. It was suggested that bud bank played an important role in the vegetation regeneration after the disturbance of soil erosion on the hilly-gully Loess Plateau of North Shaanxi.

TCDD Inhibition of Canonical Wnt Signaling Disrupts Prostatic Bud Formation in Mouse Urogenital Sinus

PubMed Central

Peterson, Richard E.

2013-01-01

In mice, in utero exposure to 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD) reduces the number of dorsolateral prostatic buds resulting in a smaller dorsolateral prostate and prevents formation of ventral buds culminating in ventral prostate agenesis. The genes and signaling pathways affected by TCDD that are responsible for disrupting prostate development are largely unknown. Here we show that treatment of urogenital sinus (UGS) organ cultures with known inhibitors of canonical Wnt signaling also inhibits prostatic bud formation. In support of the hypothesis that TCDD decreases canonical Wnt signaling, we identify inhibitory effects of TCDD on multiple components of the canonical Wnt signaling pathway in the UGS that temporally coincide with the inhibitory effect of TCDD on prostatic bud formation: (1) expression of R-spondins (Rspo2 and Rspo3) that promote canonical Wnt signaling is reduced; (2) expression of Lef1, Tcf1, and Wif1, established canonical Wnt target genes, is decreased; (3) expression of Lgr5, a RSPO receptor that activates canonical Wnt signaling, is reduced; and (4) expression of Dickkopfs (Dkks), inhibitors of canonical Wnt signaling, is not increased by TCDD. Thus, the TCDD-induced reduction in canonical Wnt signaling is associated with a decrease in activators (Rspo2 and Rspo3) rather than an increase in inhibitors (Dkk1 and Dkk2) of the pathway. This study focuses on determining whether treatment of TCDD-exposed UGS organ cultures with RSPO2 and/or RSPO3 is capable of rescuing the inhibitory effects of TCDD on canonical Wnt signaling and prostatic bud formation. We discovered that each RSPO alone or in combination partially rescues TCDD inhibition of both canonical Wnt signaling and prostatic bud formation. PMID:23429912

TCDD inhibition of canonical Wnt signaling disrupts prostatic bud formation in mouse urogenital sinus.

PubMed

Branam, Amanda M; Davis, Nicole M; Moore, Robert W; Schneider, Andrew J; Vezina, Chad M; Peterson, Richard E

2013-05-01

In mice, in utero exposure to 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD) reduces the number of dorsolateral prostatic buds resulting in a smaller dorsolateral prostate and prevents formation of ventral buds culminating in ventral prostate agenesis. The genes and signaling pathways affected by TCDD that are responsible for disrupting prostate development are largely unknown. Here we show that treatment of urogenital sinus (UGS) organ cultures with known inhibitors of canonical Wnt signaling also inhibits prostatic bud formation. In support of the hypothesis that TCDD decreases canonical Wnt signaling, we identify inhibitory effects of TCDD on multiple components of the canonical Wnt signaling pathway in the UGS that temporally coincide with the inhibitory effect of TCDD on prostatic bud formation: (1) expression of R-spondins (Rspo2 and Rspo3) that promote canonical Wnt signaling is reduced; (2) expression of Lef1, Tcf1, and Wif1, established canonical Wnt target genes, is decreased; (3) expression of Lgr5, a RSPO receptor that activates canonical Wnt signaling, is reduced; and (4) expression of Dickkopfs (Dkks), inhibitors of canonical Wnt signaling, is not increased by TCDD. Thus, the TCDD-induced reduction in canonical Wnt signaling is associated with a decrease in activators (Rspo2 and Rspo3) rather than an increase in inhibitors (Dkk1 and Dkk2) of the pathway. This study focuses on determining whether treatment of TCDD-exposed UGS organ cultures with RSPO2 and/or RSPO3 is capable of rescuing the inhibitory effects of TCDD on canonical Wnt signaling and prostatic bud formation. We discovered that each RSPO alone or in combination partially rescues TCDD inhibition of both canonical Wnt signaling and prostatic bud formation.

Isolation and characterization of the Jatropha curcas APETALA1 (JcAP1) promoter conferring preferential expression in inflorescence buds.

PubMed

Tao, Yan-Bin; He, Liang-Liang; Niu, Longjian; Xu, Zeng-Fu

2016-08-01

The 1.5 kb JcAP1 promoter from the biofuel plant Jatropha curcas is predominantly active in the inflorescence buds of transgenic plants, in which the -1313/-1057 region is essential for maintaining the activity. Arabidopsis thaliana APETALA1 (AP1) is a MADS-domain transcription factor gene that functions primarily in flower development. We isolated a homolog of AP1 from Jatropha curcas (designated JcAP1), which was shown to exhibit flower-specific expression in Jatropha. JcAP1 is first expressed in inflorescence buds and continues to be primarily expressed in the sepals. We isolated a 1.5 kb JcAP1 promoter and evaluated its activity in transgenic Arabidopsis and Jatropha using the β-glucuronidase (GUS) reporter gene. In transgenic Arabidopsis and Jatropha, the inflorescence buds exhibited notable GUS activity, whereas the sepals did not. Against expectations, the JcAP1 promoter was active in the anthers of Arabidopsis and Jatropha and was highly expressed in Jatropha seeds. An analysis of promoter deletions in transgenic Arabidopsis revealed that deletion of the -1313/-1057 region resulted in loss of JcAP1 promoter activity in the inflorescence buds and increased activity in the anthers. These results suggested that some regulatory sequences in the -1313/-1057 region are essential for maintaining promoter activity in inflorescence buds and can partly suppress activity in the anthers. Based on these findings, we hypothesized that other elements located upstream of the 1.5 kb JcAP1 promoter may be required for flower-specific activation. The JcAP1 promoter characterized in this study can be used to drive transgene expression in both the inflorescence buds and seeds of Jatropha.

Intra-arterial bromodeoxyuridine radiosensitization of malignant gliomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hegarty, T.J.; Thornton, A.F.; Diaz, R.F.

1990-08-01

In the 1950's it was first observed that mammalian cells exposed to the halogenated deoxyuridines were more sensitive to ultraviolet light and radiation than untreated cells. This prompted early clinical trials with bromodeoxyuridine (BUdR) which showed mixed results. More recently, several Phase I studies, while establishing the feasibility of continuous intravenous (IV) infusion of BUdR, have reported significant dose limiting skin and bone marrow toxicities and have questioned the optimal method of BUdR delivery. To exploit the high mitotic activity of malignant gliomas relative to surrounding normal brain tissue, we have developed a permanently implantable infusion pump system for safe,more » continuous intraarterial (IA) internal carotid BUdR delivery. Since July 1985, 23 patients with malignant brain tumors (18 grade 4, 5 grade 3) have been treated in a Phase I clinical trial using IA BUdR (400-600 mg/m2/day X 8 1/2 weeks) and focal external beam radiotherapy (59.4 Gy at 1.8 Gy/day in 6 1/2 weeks). Following initial biopsy/surgery the infusion pump system was implanted; BUdR infusion began 2 weeks prior to and continued throughout the 6 1/2 week course of radiotherapy. There have been no vascular complications. Side-effects in all patients have included varying degrees of anorexia, fatigue, ipsilateral forehead dermatitis, blepharitis, and conjunctivitis. Myelosuppression requiring dose reduction occurred in one patient. An overall Kaplan-Meier estimated median survival of 20 months has been achieved. As in larger controlled series, histologic grade and age are prognostically significant. We have shown in a Phase I study that IA BUdR radiosensitization is safe, tolerable, may lead to improved survival, and appears to be an efficacious primary treatment of malignant gliomas.« less

Dormancy in Peach (Prunus persica L.) Flower Buds : I. Floral Morphogenesis and Endogenous Gibberellins at the End of the Dormancy Period.

PubMed

Luna, V; Lorenzo, E; Reinoso, H; Tordable, M C; Abdala, G; Pharis, R P; Bottini, R

1990-05-01

Flower buds of peach (Prunus persica L.) trees, cv Novedad de Cordoba (Argentina), were collected near the end of the dormant period and immediately before anthesis. After removal of scale leaves, morphological observations of representative buds, made on transverse and longitudinal microtome sections, showed that all verticils making up the flower are present in an undifferentiated form during the dormant period (June). Flower buds collected at the end of dormant period (August) showed additional growth and differentiation, at which time formation of two ovules was beginning in the unicarpelar gynoecium. Dehiscence of anthers had not yet occurred 10 days before full bloom, and the ovules were still developing. Free endogenous gibberellin (GA)-like substances were quantified by bioassay (Tan-ginbozu dwarf rice microdrop) after SiO(2) partition column chromatography, reversed phase C18-high performance liquid chromatography, and finally Nucleosil [N(CH(3))(2)]high performance liquid chromatography. Bioactive fractions were then subjected to capillary gas chromatography-mass spectrometry-selected ion monitoring (GC-MS-SIM). Gibberellins A(1), A(3), and A(8) were tentatively identified in peach flower buds using GC-SIM and Kovat's retention indices, and relative amounts approximated by GC-SIM (2:8:6 for GA(1), GA(3), and GA(8), respectively). The highest concentration (330 nanograms per gram dry weight) of free GA(1)/GA(3) was found in dormant buds (June) and diminished thereafter. The concentration free of GA(1)/GA(3) did not increase immediately prior to bud break. However, high GA(1)/GA(3) concentrations occurred during stages where rate of growth and cellular differentiation of (mainly fertile) verticils can be influenced.

Development of the pseudothumb in frogs

PubMed Central

Tokita, Masayoshi; Iwai, Noriko

2010-01-01

Frogs have highly conserved hand and foot morphology, possessing four fingers and five toes. As an exception, two Japanese ranid frog species, the Otton frog Babina subaspera and the dagger frog Babina holsti, possess a unique thumb-like structure (the pseudothumb) in the forelimb, giving an appearance of a total of five fingers on the hand. To obtain insights into the developmental mechanisms that generate this novel character, we investigated the hand morphogenesis of the Otton frog. The unique morphological pattern of the pseudothumb was already established in juveniles. Surprisingly, the bud-like structure, which is similar to the area of inductive activity (e.g. feather buds in birds and the carapacial ridge in turtles), was detected over the site where the future prepollex develops in larvae. By contrast, this bud-like structure was not found in larvae of other ranid species. We discuss possible scenarios that would favour the evolution of this very unusual trait in frogs. PMID:20147308

Sex-Biased Temporal Gene Expression in Male and Female Floral Buds of Seabuckthorn (Hippophae rhamnoides).

PubMed

Chawla, Aseem; Stobdan, Tsering; Srivastava, Ravi B; Jaiswal, Varun; Chauhan, Rajinder S; Kant, Anil

2015-01-01

Seabuckthorn is an economically important dioecious plant in which mechanism of sex determination is unknown. The study was conducted to identify seabuckthorn homologous genes involved in floral development which may have role in sex determination. Forty four putative Genes involved in sex determination (GISD) reported in model plants were shortlisted from literature survey, and twenty nine seabuckthorn homologous sequences were identified from available seabuckthorn genomic resources. Of these, 21 genes were found to differentially express in either male or female flower bud stages. HrCRY2 was significantly expressed in female flower buds only while HrCO had significant expression in male flowers only. Among the three male and female floral development stages (FDS), male stage II had significant expression of most of the GISD. Information on these sex-specific expressed genes will help in elucidating sex determination mechanism in seabuckthorn.

Sex-Biased Temporal Gene Expression in Male and Female Floral Buds of Seabuckthorn (Hippophae rhamnoides)

PubMed Central

Chawla, Aseem; Stobdan, Tsering; Srivastava, Ravi B.; Jaiswal, Varun; Chauhan, Rajinder S.; Kant, Anil

2015-01-01

Seabuckthorn is an economically important dioecious plant in which mechanism of sex determination is unknown. The study was conducted to identify seabuckthorn homologous genes involved in floral development which may have role in sex determination. Forty four putative Genes involved in sex determination (GISD) reported in model plants were shortlisted from literature survey, and twenty nine seabuckthorn homologous sequences were identified from available seabuckthorn genomic resources. Of these, 21 genes were found to differentially express in either male or female flower bud stages. HrCRY2 was significantly expressed in female flower buds only while HrCO had significant expression in male flowers only. Among the three male and female floral development stages (FDS), male stage II had significant expression of most of the GISD. Information on these sex-specific expressed genes will help in elucidating sex determination mechanism in seabuckthorn. PMID:25915052

Mathematical and statistical models for determining the crop load in grapevine

NASA Astrophysics Data System (ADS)

Alina, Dobrei; Alin, Dobrei; Eleonora, Nistor; Teodor, Cristea; Marius, Boldea; Florin, Sala

2016-06-01

Ensuring a balance between vine crop load and vine vegetative growth is a dynamic process, so it is necessary to develop models for describing this relationship. This study analyzed the interrelationship between the crop load and growing specific parameters (viable buds - VB, dead (frost-injured) buds - DB, total shoots growth-TSG, one-year-old wood - MSG), in two vine grapes varieties: Muscat Ottonel cultivar for wine and Victoria cultivar for fresh grapes. In both varieties interrelationship between the buds number and vegetative growth parameters were described by polynomial functions statistically assured. Using regression analysis it was possible to develop predictive models for one-year-old wood (MSG), an important parameter for the yield and quality of wine grape production, with statistical significance results (R2 = 0.884, p <0.001, F = 45.957 in Muscat Ottonel cultivar and R2 = 0.893, p = 0.001, F = 49.886 in Victoria cultivar).

Internal development of vegetative buds of Norway spruce trees in relation to accumulated chilling and forcing temperatures.

PubMed

Viherä-Aarnio, Anneli; Sutinen, Sirkka; Partanen, Jouni; Häkkinen, Risto

2014-05-01

The timing of budburst of temperate trees is known to be controlled by complicated interactions of temperature and photoperiod. To improve the phenological models of budburst, better knowledge of the internal bud development preceding budburst in relation to environmental cues is needed. We studied the effect of accumulated chilling and forcing temperatures on the internal development of vegetative buds preceding budburst in Norway spruce [Picea abies (L.) Karst.]. Branches from 17-year-old trees of southern Finnish origin were transferred eight times at 1- to 2-week intervals from October to December 2007 from the field at Punkaharju (61°48'N, 29°20'E) to the greenhouse with forcing conditions (day length 12 h, +20 °C). After seven different durations of forcing, the developmental phase and primordial shoot growth of the buds were analysed at the stereomicroscopic level. Air temperature was recorded hourly throughout the study period. The accumulated chilling unit sum had a significant effect on the temperature sum that was required to attain a certain developmental phase; a higher amount of chilling required a lower amount of forcing. The variation in the rate of development of different buds within each sample branch in relation to the chilling unit and forcing temperature sum was low. Regarding primordial shoot growth, there was also an inverse relation between accumulated chilling and forcing, i.e., a higher accumulated chilling unit sum before forcing required a lower temperature sum to initiate primordial shoot growth and resulted in a stronger effect of accumulated forcing. A second-order regression model with an interaction of chilling and forcing explained the variation of primordial shoot growth with high precision (R(2) = 0.88). However, further studies are required to determine the final parameter values to be used in phenological modelling. © The Author 2014. Published by Oxford University Press. All rights reserved.

Temporal and spatial variation of terpenoids in eastern hemlock (Tsuga canadensis) in relation to feeding by Adelges tsugae

Treesearch

Anthony F. Lagalante; Nyssa Lewis; Michael E. Montgomery; Kathleen S. Shields

2006-01-01

The terpenoid content of eastern hemlock (Tsuga canadensis) foliage was measured over an annual cycle of development from bud opening, shoot elongation, shoot maturation, to bud-break at the start of the next growing season. The objective was to determine if variation in terpenoid composition is linked with spatial and temporal feeding preferences of...

Induction of ectopic taste buds by SHH reveals the competency and plasticity of adult lingual epithelium

PubMed Central

Castillo, David; Seidel, Kerstin; Salcedo, Ernesto; Ahn, Christina; de Sauvage, Frederic J.; Klein, Ophir D.; Barlow, Linda A.

2014-01-01

Taste buds are assemblies of elongated epithelial cells, which are innervated by gustatory nerves that transmit taste information to the brain stem. Taste cells are continuously renewed throughout life via proliferation of epithelial progenitors, but the molecular regulation of this process remains unknown. During embryogenesis, sonic hedgehog (SHH) negatively regulates taste bud patterning, such that inhibition of SHH causes the formation of more and larger taste bud primordia, including in regions of the tongue normally devoid of taste buds. Here, using a Cre-lox system to drive constitutive expression of SHH, we identify the effects of SHH on the lingual epithelium of adult mice. We show that misexpression of SHH transforms lingual epithelial cell fate, such that daughter cells of lingual epithelial progenitors form cell type-replete, onion-shaped taste buds, rather than non-taste, pseudostratified epithelium. These SHH-induced ectopic taste buds are found in regions of the adult tongue previously thought incapable of generating taste organs. The ectopic buds are composed of all taste cell types, including support cells and detectors of sweet, bitter, umami, salt and sour, and recapitulate the molecular differentiation process of endogenous taste buds. In contrast to the well-established nerve dependence of endogenous taste buds, however, ectopic taste buds form independently of both gustatory and somatosensory innervation. As innervation is required for SHH expression by endogenous taste buds, our data suggest that SHH can replace the need for innervation to drive the entire program of taste bud differentiation. PMID:24993944

Jacalin and peanut agglutinin (PNA) bindings in the taste bud cells of the rat: new reliable markers for type IV cells of the rat taste buds.

PubMed

Taniguchi, Ryo; Shi, Lei; Fujii, Masae; Ueda, Katsura; Honma, Shiho; Wakisaka, Satoshi

2005-12-01

Lectin histochemistry of Jacalin (Artocarpus integrifolia) and peanut agglutinin (PNA), specific lectins for galactosyl (beta-1, 3) N-acetylgalactosamine (galactosyl (beta-1, 3) GalNAc), was applied to the gustatory epithelium of the adult rat. In the ordinary lingual epithelium, Jacalin and PNA labeled the cell membrane from the basal to granular cell layer. They also bound membranes of rounded-cells at the basal portion of taste buds, but the number of PNA labeled cells was smaller than that of Jacalin labeled cells. There was no apparent difference in the binding patterns of Jacalin and PNA among the taste buds of the lingual papillae and those of the palatal epithelium. Occasionally, a few spindle-shaped cells were labeled with Jacalin, but not with PNA. Double labeling of Jacalin and alpha-gustducin, a specific marker for type II cells, revealed that Jacalin-labeled spindle-shaped taste cells were immunonegative for alpha-gustducin. Spindle-shaped cells expressing protein gene product 9.5 (PGP 9.5) immunoreactivity lacked Jacalin labeling. During the development of taste buds in circumvallate papillae, the binding pattern of Jacalin became almost identical from postnatal day 5. The present results indicate that rounded cells at the basal portion of the taste buds cells (type IV cells) bind to Jacalin and PNA, and these lectins are specific markers for type IV cells of the rat taste cells.

Dormancy release and flowering time in Ziziphus jujuba Mill., a "direct flowering" fruit tree, has a facultative requirement for chilling.

PubMed

Meir, Michal; Ransbotyn, Vanessa; Raveh, Eran; Barak, Simon; Tel-Zur, Noemi; Zaccai, Michele

2016-03-15

In deciduous fruit trees, the effect of chilling on flowering has mostly been investigated in the "indirect flowering" group, characterized by a period of rest between flower bud formation and blooming. In the present study, we explored the effects of chilling and chilling deprivation on the flowering of Ziziphus jujuba, a temperate deciduous fruit tree belonging to the "direct flowering" group, in which flower bud differentiation, blooming and fruit development occur after dormancy release, during a single growing season. Dormancy release, vegetative growth and flowering time in Z. jujuba cv. Ben-Li were assessed following several treatments of chilling. Chilling treatments quantitatively decreased the timing of vegetative bud dormancy release, thereby accelerating flowering, but had no effect on the time from dormancy release to flowering. Trees grown at a constant temperature of 25°C, without chilling, broke dormancy and flowered, indicating the facultative character of chilling in this species. We measured the expression of Z. jujuba LFY and AP1 homologues (ZjLFY and ZjAP1). Chilling decreased ZjLFY expression in dormant vegetative buds but had no effect on ZjAP1expression, which reached peak expression before dormancy release and at anthesis. In conclusion, chilling is not obligatory for dormancy release of Z. jujuba cv. Ben-Li vegetative buds. However, the exposure to chilling during dormancy does accelerate vegetative bud dormancy release and flowering. Copyright © 2016 Elsevier GmbH. All rights reserved.

Deep-time evolution of regeneration and preaxial polarity in tetrapod limb development.

PubMed

Fröbisch, Nadia B; Bickelmann, Constanze; Olori, Jennifer C; Witzmann, Florian

2015-11-12

Among extant tetrapods, salamanders are unique in showing a reversed preaxial polarity in patterning of the skeletal elements of the limbs, and in displaying the highest capacity for regeneration, including full limb and tail regeneration. These features are particularly striking as tetrapod limb development has otherwise been shown to be a highly conserved process. It remains elusive whether the capacity to regenerate limbs in salamanders is mechanistically and evolutionarily linked to the aberrant pattern of limb development; both are features classically regarded as unique to urodeles. New molecular data suggest that salamander-specific orphan genes play a central role in limb regeneration and may also be involved in the preaxial patterning during limb development. Here we show that preaxial polarity in limb development was present in various groups of temnospondyl amphibians of the Carboniferous and Permian periods, including the dissorophoids Apateon and Micromelerpeton, as well as the stereospondylomorph Sclerocephalus. Limb regeneration has also been reported in Micromelerpeton, demonstrating that both features were already present together in antecedents of modern salamanders 290 million years ago. Furthermore, data from lepospondyl 'microsaurs' on the amniote stem indicate that these taxa may have shown some capacity for limb regeneration and were capable of tail regeneration, including re-patterning of the caudal vertebral column that is otherwise only seen in salamander tail regeneration. The data from fossils suggest that salamander-like regeneration is an ancient feature of tetrapods that was subsequently lost at least once in the lineage leading to amniotes. Salamanders are the only modern tetrapods that retained regenerative capacities as well as preaxial polarity in limb development.

Tongue and taste organ development in the ontogeny of direct-developing salamander Plethodon cinereus (Lissamphibia: Plethodontidae).

PubMed

Budzik, Karolina A; Żuwała, Krystyna; Kerney, Ryan

2016-07-01

The latest research on direct developing caecilian and anuran species indicate presence of only one generation of taste organs during their ontogeny. This is distinct from indirect developing batrachians studied thus far, which possess taste buds in larvae and anatomically distinct taste discs in metamorphs. This study is a description of the tongue and taste organ morphology and development in direct developing salamander Plethodon cinereus (Plethodontidae) using histology and electron microscopy techniques. The results reveal two distinct stages tongue morphology (primary and secondary), similar to metamorphic urodeles, although only one stage of taste organ morphology. Taste disc sensory zones emerge on the surface of the oropharyngeal epithelium by the end of embryonic development, which coincides with maturation of the soft tongue. Taste organs occur in the epithelium of the tongue pad (where they are situated on the dermal papillae), the palate and the inner surface of the mandible and the maxilla. Plethodon cinereus embryos only possess taste disc type taste organs. Similar to the direct developing anuran Eleutherodactylus coqui (Eleutherodactylidae), these salamanders do not recapitulate larval taste bud morphology as an embryo. The lack of taste bud formation is probably a broadly distributed feature characteristic to direct developing batrachians. J. Morphol. 277:906-915, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Neurological problems of jazz legends.

PubMed

Pearl, Phillip L

2009-08-01

A variety of neurological problems have affected the lives of giants in the jazz genre. Cole Porter courageously remained prolific after severe leg injuries secondary to an equestrian accident, until he succumbed to osteomyelitis, amputations, depression, and phantom limb pain. George Gershwin resisted explanations for uncinate seizures and personality change and herniated from a right temporal lobe brain tumor, which was a benign cystic glioma. Thelonious Monk had erratic moods, reflected in his pianism, and was ultimately mute and withdrawn, succumbing to cerebrovascular events. Charlie Parker dealt with mood lability and drug dependence, the latter emanating from analgesics following an accident, and ultimately lived as hard as he played his famous bebop saxophone lines and arpeggios. Charles Mingus hummed his last compositions into a tape recorder as he died with motor neuron disease. Bud Powell had severe posttraumatic headaches after being struck by a police stick defending Thelonious Monk during a Harlem club raid.

Volumetry of human taste buds using laser scanning microscopy.

PubMed

Just, T; Srur, E; Stachs, O; Pau, H W

2009-10-01

In vivo laser scanning confocal microscopy is a relatively new, non-invasive method for assessment of oral cavity epithelia. The penetration depth of approximately 200-400 microm allows visualisation of fungiform papillae and their taste buds. This paper describes the technique of in vivo volumetry of human taste buds. Confocal laser scanning microscopy used a diode laser at 670 nm for illumination. Digital laser scanning confocal microscopy equipment consisted of the Heidelberg Retina Tomograph HRTII and the Rostock Cornea Module. Volume scans of fungiform papillae were used for three-dimensional reconstruction of the taste bud. This technique supplied information on taste bud structure and enabled measurement and calculation of taste bud volume. Volumetric data from a 23-year-old man over a nine-day period showed only a small deviation in values. After three to four weeks, phenomenological changes in taste bud structures were found (i.e. a significant increase in volume, followed by disappearance of the taste bud and appearance of a new taste bud). The data obtained indicate the potential application of this non-invasive imaging modality: to evaluate variation of taste bud volume in human fungiform papillae with ageing; to study the effects of chorda tympani nerve transection on taste bud volume; and to demonstrate recovery of taste buds in patients with a severed chorda tympani nerve who show recovery of gustatory sensibility after surgery.

Mitochondrial anchorage and fusion contribute to mitochondrial inheritance and quality control in the budding yeast Saccharomyces cerevisiae

PubMed Central

Higuchi-Sanabria, Ryo; Charalel, Joseph K.; Viana, Matheus P.; Garcia, Enrique J.; Sing, Cierra N.; Koenigsberg, Andrea; Swayne, Theresa C.; Vevea, Jason D.; Boldogh, Istvan R.; Rafelski, Susanne M.; Pon, Liza A.

2016-01-01

Higher-functioning mitochondria that are more reduced and have less ROS are anchored in the yeast bud tip by the Dsl1-family protein Mmr1p. Here we report a role for mitochondrial fusion in bud-tip anchorage of mitochondria. Fluorescence loss in photobleaching (FLIP) and network analysis experiments revealed that mitochondria in large buds are a continuous reticulum that is physically distinct from mitochondria in mother cells. FLIP studies also showed that mitochondria that enter the bud can fuse with mitochondria that are anchored in the bud tip. In addition, loss of fusion and mitochondrial DNA (mtDNA) by deletion of mitochondrial outer or inner membrane fusion proteins (Fzo1p or Mgm1p) leads to decreased accumulation of mitochondria at the bud tip and inheritance of fitter mitochondria by buds compared with cells with no mtDNA. Conversely, increasing the accumulation and anchorage of mitochondria in the bud tip by overexpression of MMR1 results in inheritance of less-fit mitochondria by buds and decreased replicative lifespan and healthspan. Thus quantity and quality of mitochondrial inheritance are ensured by two opposing processes: bud-tip anchorage by mitochondrial fusion and Mmr1p, which favors bulk inheritance; and quality control mechanisms that promote segregation of fitter mitochondria to the bud. PMID:26764088

Frost hardiness of tree species is independent of phenology and macroclimatic niche.

PubMed

Hofmann, M; Bruelheide, H

2015-03-01

The differences in timing in bud burst between species have been interpreted as an adaptation to late frost events in spring. Thus, it has been suggested that the degree of frost susceptibility of leaves is species-specific and depends on the species' phenology and geographic distribution range. To test for relationships between frost tolerance and phenology as well as between frost tolerance and distribution range across Central European tree species, we studied the frost hardiness of closed buds before bud burst and of freshly opened buds at the time of bud burst. We hypothesized that species with early bud burst and species distributed in eastern and northern areas were more frost tolerant than species with late bud burst and species distributed in western and southern areas. Frost hardiness was estimated by exposing twigs to 11 frost temperatures between -4 °C and -80 °C and by assessing tissue damage by the electrolyte leakage method. In contrast to our hypotheses, neither frost hardiness of closed buds nor frost hardiness of freshly opened buds were related to any variable describing species' macroclimatic niche. Furthermore, frost hardiness of freshly opened buds did not differ among species. Thus, the investigated species with early bud burst take higher risks of frost damage than the species with late bud bursts. These findings indicate that frost hardiness might not play the key role in limiting the geographic distribution ranges previously anticipated.

Postnatal reduction of BDNF regulates the developmental remodeling of taste bud innervation.

PubMed

Huang, Tao; Ma, Liqun; Krimm, Robin F

2015-09-15

The refinement of innervation is a common developmental mechanism that serves to increase the specificity of connections following initial innervation. In the peripheral gustatory system, the extent to which innervation is refined and how refinement might be regulated is unclear. The initial innervation of taste buds is controlled by brain-derived neurotrophic factor (BDNF). Following initial innervation, taste receptor cells are added and become newly innervated. The connections between the taste receptor cells and nerve fibers are likely to be specific in order to retain peripheral coding mechanisms. Here, we explored the possibility that the down-regulation of BDNF regulates the refinement of taste bud innervation during postnatal development. An analysis of BDNF expression in Bdnf(lacZ/+) mice and real-time reverse transcription polymerase chain reaction (RT-PCR) revealed that BDNF was down-regulated between postnatal day (P) 5 and P10. This reduction in BDNF expression was due to a loss of precursor/progenitor cells that express BDNF, while the expression of BDNF in the subpopulations of taste receptor cells did not change. Gustatory innervation, which was identified by P2X3 immunohistochemistry, was lost around the perimeter where most progenitor/precursor cells are located. In addition, the density of innervation in the taste bud was reduced between P5 and P10, because taste buds increase in size without increasing innervation. This reduction of innervation density was blocked by the overexpression of BDNF in the precursor/progenitor population of taste bud cells. Together these findings indicate that the process of BDNF restriction to a subpopulation of taste receptor cells between P5 and P10, results in a refinement of gustatory innervation. We speculate that this refinement results in an increased specificity of connections between neurons and taste receptor cells during development. Copyright © 2015 Elsevier Inc. All rights reserved.

Comparative transcript profiling of the fertile and sterile flower buds of pol CMS in B. napus.

PubMed

An, Hong; Yang, Zonghui; Yi, Bin; Wen, Jing; Shen, Jinxiong; Tu, Jinxing; Ma, Chaozhi; Fu, Tingdong

2014-04-03

The Polima (pol) system of cytoplasmic male sterility (CMS) and its fertility restoration gene Rfp have been used in hybrid breeding in Brassica napus, which has greatly improved the yield of rapeseed. However, the mechanism of the male sterility transition in pol CMS remains to be determined. To investigate the transcriptome during the male sterility transition in pol CMS, a near-isogenic line (NIL) of pol CMS was constructed. The phenotypic features and sterility stage were confirmed by anatomical analysis. Subsequently, we compared the genomic expression profiles of fertile and sterile young flower buds by RNA-Seq. A total of 105,481,136 sequences were successfully obtained. These reads were assembled into 112,770 unigenes, which composed the transcriptome of the bud. Among these unigenes, 72,408 (64.21%) were annotated using public protein databases and classified into functional clusters. In addition, we investigated the changes in expression of the fertile and sterile buds; the RNA-seq data showed 1,148 unigenes had significantly different expression and they were mainly distributed in metabolic and protein synthesis pathways. Additionally, some unigenes controlling anther development were dramatically down-regulated in sterile buds. These results suggested that an energy deficiency caused by orf224/atp6 may inhibit a series of genes that regulate pollen development through nuclear-mitochondrial interaction. This results in the sterility of pol CMS by leading to the failure of sporogenous cell differentiation. This study may provide assistance for detailed molecular analysis and a better understanding of pol CMS in B. napus.

Spring frost vulnerability of sweet cherries under controlled conditions

NASA Astrophysics Data System (ADS)

Matzneller, Philipp; Götz, Klaus-P.; Chmielewski, Frank-M.

2016-01-01

Spring frost is a significant production hazard in nearly all temperate fruit-growing regions. Sweet cherries are among the first fruit varieties starting their development in spring and therefore highly susceptible to late frost. Temperatures at which injuries are likely to occur are widely published, but their origin and determination methods are not well documented. In this study, a standardized method was used to investigate critical frost temperatures for the sweet cherry cultivar `Summit' under controlled conditions. Twigs were sampled at four development stages ("side green," "green tip," "open cluster," "full bloom") and subjected to three frost temperatures (-2.5, -5.0, -10.0 °C). The main advantage of this method, compared to other approaches, was that the exposition period and the time interval required to reach the target temperature were always constant (2 h). Furthermore, then, the twigs were placed in a climate chamber until full bloom, before the examination of the flowers and not further developed buds started. For the first two sampling stages (side green, green tip), the number of buds found in open cluster, "first white," and full bloom at the evaluation date decreased with the strength of the frost treatment. The flower organs showed different levels of cold hardiness and became more vulnerable in more advanced development stages. In this paper, we developed four empirical functions which allow calculating possible frost damages on sweet cherry buds or flowers at the investigated development stages. These equations can help farmers to estimate possible frost damages on cherry buds due to frost events. However, it is necessary to validate the critical temperatures obtained in laboratory with some field observations.

Spring frost vulnerability of sweet cherries under controlled conditions.

PubMed

Matzneller, Philipp; Götz, Klaus-P; Chmielewski, Frank-M

2016-01-01

Spring frost is a significant production hazard in nearly all temperate fruit-growing regions. Sweet cherries are among the first fruit varieties starting their development in spring and therefore highly susceptible to late frost. Temperatures at which injuries are likely to occur are widely published, but their origin and determination methods are not well documented. In this study, a standardized method was used to investigate critical frost temperatures for the sweet cherry cultivar 'Summit' under controlled conditions. Twigs were sampled at four development stages ("side green," "green tip," "open cluster," "full bloom") and subjected to three frost temperatures (-2.5, -5.0, -10.0 °C). The main advantage of this method, compared to other approaches, was that the exposition period and the time interval required to reach the target temperature were always constant (2 h). Furthermore, then, the twigs were placed in a climate chamber until full bloom, before the examination of the flowers and not further developed buds started. For the first two sampling stages (side green, green tip), the number of buds found in open cluster, "first white," and full bloom at the evaluation date decreased with the strength of the frost treatment. The flower organs showed different levels of cold hardiness and became more vulnerable in more advanced development stages. In this paper, we developed four empirical functions which allow calculating possible frost damages on sweet cherry buds or flowers at the investigated development stages. These equations can help farmers to estimate possible frost damages on cherry buds due to frost events. However, it is necessary to validate the critical temperatures obtained in laboratory with some field observations.

Neurochemical characterization of sea lamprey taste buds and afferent gustatory fibers: presence of serotonin, calretinin, and CGRP immunoreactivity in taste bud bi-ciliated cells of the earliest vertebrates.

PubMed

Barreiro-Iglesias, Antón; Villar-Cerviño, Verona; Villar-Cheda, Begoña; Anadón, Ramón; Rodicio, María Celina

2008-12-01

Neuroactive substances such as serotonin and other monoamines have been suggested to be involved in the transmission of gustatory signals from taste bud cells to afferent fibers. Lampreys are the earliest vertebrates that possess taste buds, although these differ in structure from taste buds in jawed vertebrates, and their neurochemistry remains unknown. We used immunofluorescence methods with antibodies raised against serotonin, tyrosine hydroxylase (TH), gamma-aminobutyric acid (GABA), glutamate, calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), calretinin, and acetylated alpha-tubulin to characterize the neurochemistry and innervation of taste buds in the sea lamprey, Petromyzon marinus L. For localization of proliferative cells in taste buds we used bromodeoxyuridine labeling and proliferating cell nuclear antigen immunohistochemistry. Results with both markers indicate that proliferating cells are restricted to a few basal cells and that almost all cells in taste buds are nonproliferating. A large number of serotonin-, calretinin-, and CGRP-immunoreactive bi-ciliated cells were revealed in lamprey taste buds. This suggests that serotonin participates in the transmission of gustatory signals and indicates that this substance appeared early on in vertebrate evolution. The basal surface of the bi-ciliated taste bud cells was contacted by tubulin-immunoreactive fibers. Some of the fibers surrounding the taste bud were calretinin immunoreactive. Lamprey taste bud cells or afferent fibers did not exhibit TH, GABA, glutamate, or NPY immunoreactivity, which suggests that expression of these substances evolved in taste buds of some gnathostomes lines after the separation of gnathostomes and lampreys. (c) 2008 Wiley-Liss, Inc.

Induction of ectopic taste buds by SHH reveals the competency and plasticity of adult lingual epithelium.

PubMed

Castillo, David; Seidel, Kerstin; Salcedo, Ernesto; Ahn, Christina; de Sauvage, Frederic J; Klein, Ophir D; Barlow, Linda A

2014-08-01

Taste buds are assemblies of elongated epithelial cells, which are innervated by gustatory nerves that transmit taste information to the brain stem. Taste cells are continuously renewed throughout life via proliferation of epithelial progenitors, but the molecular regulation of this process remains unknown. During embryogenesis, sonic hedgehog (SHH) negatively regulates taste bud patterning, such that inhibition of SHH causes the formation of more and larger taste bud primordia, including in regions of the tongue normally devoid of taste buds. Here, using a Cre-lox system to drive constitutive expression of SHH, we identify the effects of SHH on the lingual epithelium of adult mice. We show that misexpression of SHH transforms lingual epithelial cell fate, such that daughter cells of lingual epithelial progenitors form cell type-replete, onion-shaped taste buds, rather than non-taste, pseudostratified epithelium. These SHH-induced ectopic taste buds are found in regions of the adult tongue previously thought incapable of generating taste organs. The ectopic buds are composed of all taste cell types, including support cells and detectors of sweet, bitter, umami, salt and sour, and recapitulate the molecular differentiation process of endogenous taste buds. In contrast to the well-established nerve dependence of endogenous taste buds, however, ectopic taste buds form independently of both gustatory and somatosensory innervation. As innervation is required for SHH expression by endogenous taste buds, our data suggest that SHH can replace the need for innervation to drive the entire program of taste bud differentiation. © 2014. Published by The Company of Biologists Ltd.

Wnt affects symmetry and morphogenesis during post-embryonic development in colonial chordates.

PubMed

Di Maio, Alessandro; Setar, Leah; Tiozzo, Stefano; De Tomaso, Anthony W

2015-01-01

Wnt signaling is one of the earliest and most highly conserved regulatory pathways for the establishment of the body axes during regeneration and early development. In regeneration, body axes determination occurs independently of tissue rearrangement and early developmental cues. Modulation of the Wnt signaling in either process has shown to result in unusual body axis phenotypes. Botryllus schlosseri is a colonial ascidian that can regenerate its entire body through asexual budding. This processes leads to an adult body via a stereotypical developmental pathway (called blastogenesis), without proceeding through any embryonic developmental stages. In this study, we describe the role of the canonical Wnt pathway during the early stages of asexual development. We characterized expression of three Wnt ligands (Wnt2B, Wnt5A, and Wnt9A) by in situ hybridization and qRT-PCR. Chemical manipulation of the pathway resulted in atypical budding due to the duplication of the A/P axes, supernumerary budding, and loss of the overall cell apical-basal polarity. Our results suggest that Wnt signaling is used for equivalent developmental processes both during embryogenesis and asexual development in an adult organism, suggesting that patterning mechanisms driving morphogenesis are conserved, independent of embryonic, or regenerative development.

Influences of tree, stand, and site characteristics on the production of epicormic branches in southern bottomland hardwood forests

Treesearch

James S. Meadows; J.C.G. Goelz; Daniel A. Skojac

2013-01-01

Epicormic branches are adventitious twigs that develop from dormant buds found along the main bole of hardwood trees. These buds may be released at any time during the life of the tree in response to various types of stimuli. Epicormic branches cause defects in the underlying wood and may cause significant reductions in both log grade and subsequent lumber value....

Phenology of slippery bark and common foliar diseases

Treesearch

Kevin T. Smith

2013-01-01

As mud season gives way to spring in New England, the pace of plant development quickens. We see that from the visual cues of plant phenology, the sequence and timing of biological events. The big early season events are upon us as the maple sap has run, buds swell, bud dormancy breaks, and leaves and flowers emerge. This is a good time for arborists to dust off their...

Crosstalk between the p190-B RhoGAP and IGF signaling pathways is required for embryonic mammary bud development

USDA-ARS?s Scientific Manuscript database

P190-B RhoGAP (p190-B, also known as ARHGAP5) has been shown to play an essential role in invasion of the terminal end buds (TEBs) into the surrounding fat pad during mammary gland ductal morphogenesis. Here we report that embryos with a homozygous p190-B gene deletion exhibit major defects in embry...

Apical and basal epitheliomuscular F-actin dynamics during Hydra bud evagination

PubMed Central

Aufschnaiter, Roland; Wedlich-Söldner, Roland; Zhang, Xiaoming

2017-01-01

ABSTRACT Bending of 2D cell sheets is a fundamental morphogenetic mechanism during animal development and reproduction. A critical player driving cell shape during tissue bending is the actin cytoskeleton. Much of our current knowledge about actin dynamics in whole organisms stems from studies of embryonic development in bilaterian model organisms. Here, we have analyzed actin-based processes during asexual bud evagination in the simple metazoan Hydra. We created transgenic Hydra strains stably expressing the actin marker Lifeact-GFP in either ectodermal or endodermal epitheliomuscular cells. We then combined live imaging with conventional phalloidin staining to directly follow actin reorganization. Bending of the Hydra epithelial double layer is initiated by a group of epitheliomuscular cells in the endodermal layer. These cells shorten their apical-basal axis and arrange their basal muscle processes in a circular configuration. We propose that this rearrangement generates the initial forces to bend the endoderm towards the ectoderm. Convergent tissue movement in both epithelial layers towards the centre of evagination then leads to elongation and extension of the bud along its new body axis. Tissue movement into the bud is associated with lateral intercalation of epithelial cells, remodelling of apical septate junctions, and rearrangement of basal muscle processes. The work presented here extends the analysis of morphogenetic mechanisms beyond embryonic tissues of model bilaterians. PMID:28630355

SVP-like MADS Box Genes Control Dormancy and Budbreak in Apple

PubMed Central

Wu, Rongmei; Tomes, Sumathi; Karunairetnam, Sakuntala; Tustin, Stuart D.; Hellens, Roger P.; Allan, Andrew C.; Macknight, Richard C.; Varkonyi-Gasic, Erika

2017-01-01

The annual growth cycle of trees is the result of seasonal cues. The onset of winter triggers an endodormant state preventing bud growth and, once a chilling requirement is satisfied, these buds enter an ecodormant state and resume growing. MADS-box genes with similarity to Arabidopsis SHORT VEGETATIVE PHASE (SVP) [the SVP-like and DORMANCY ASSOCIATED MADS-BOX (DAM) genes] have been implicated in regulating flowering and growth-dormancy cycles in perennials. Here, we identified and characterized three DAM-like (MdDAMs) and two SHORT VEGETATIVE PHASE-like (MdSVPs) genes from apple (Malus × domestica ‘Royal Gala’). The expression of MdDAMa and MdDAMc indicated they may play a role in triggering autumn growth cessation. In contrast, the expression of MdDAMb, MdSVPa and MdSVPb suggested a role in maintaining bud dormancy. Consistent with this, ectopic expression of MdDAMb and MdSVPa in ‘Royal Gala’ apple plants resulted in delayed budbreak and architecture change due to constrained lateral shoot outgrowth, but normal flower and fruit development. The association of MdSVPa and MdSVPb expression with floral bud development in the low fruiting ‘Off’ trees of a biennial bearing cultivar ‘Sciros’ suggested the SVP genes might also play a role in floral meristem identity. PMID:28421103

Comparative Genomics Reveals Accelerated Evolution in Conserved Pathways during the Diversification of Anole Lizards.

PubMed

Tollis, Marc; Hutchins, Elizabeth D; Stapley, Jessica; Rupp, Shawn M; Eckalbar, Walter L; Maayan, Inbar; Lasku, Eris; Infante, Carlos R; Dennis, Stuart R; Robertson, Joel A; May, Catherine M; Crusoe, Michael R; Bermingham, Eldredge; DeNardo, Dale F; Hsieh, Shi-Tong Tonia; Kulathinal, Rob J; McMillan, William Owen; Menke, Douglas B; Pratt, Stephen C; Rawls, Jeffery Alan; Sanjur, Oris; Wilson-Rawls, Jeanne; Wilson Sayres, Melissa A; Fisher, Rebecca E; Kusumi, Kenro

2018-02-01

Squamates include all lizards and snakes, and display some of the most diverse and extreme morphological adaptations among vertebrates. However, compared with birds and mammals, relatively few resources exist for comparative genomic analyses of squamates, hampering efforts to understand the molecular bases of phenotypic diversification in such a speciose clade. In particular, the ∼400 species of anole lizard represent an extensive squamate radiation. Here, we sequence and assemble the draft genomes of three anole species-Anolis frenatus, Anolis auratus, and Anolis apletophallus-for comparison with the available reference genome of Anolis carolinensis. Comparative analyses reveal a rapid background rate of molecular evolution consistent with a model of punctuated equilibrium, and strong purifying selection on functional genomic elements in anoles. We find evidence for accelerated evolution in genes involved in behavior, sensory perception, and reproduction, as well as in genes regulating limb bud development and hindlimb specification. Morphometric analyses of anole fore and hindlimbs corroborated these findings. We detect signatures of positive selection across several genes related to the development and regulation of the forebrain, hormones, and the iguanian lizard dewlap, suggesting molecular changes underlying behavioral adaptations known to reinforce species boundaries were a key component in the diversification of anole lizards. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

The murine homeobox gene Msx-3 shows highly restricted expression in the developing neural tube.

PubMed

Shimeld, S M; McKay, I J; Sharpe, P T

1996-04-01

The mouse homeobox-genes Msx-1 and Msx-2 are expressed in several areas of the developing embryo, including the neural tube, neural crest, facial processes and limb buds. Here we report the characterisation of a third mouse Msx gene, which we designate Msx-3. The embryonic expression of Msx-3 was found to differ from that of Msx-1 and -2 in that it was confined to the dorsal neural tube. In embryos with 5-8 somites a segmental pattern of expression was observed in the hindbrain, with rhombomeres 3 and 5 lacking Msx-3 while other rhombomeres expressed Msx-3. This pattern was transient, however, such that in embryos with 18 or more somites expression was continuous throughout the dorsal hindbrain and anterior dorsal spinal cord. Differentiation of dorsal cell types in the neural tube can be induced by addition of members of the Tgf-beta family. Additionally, Msx-1 and -2 have been shown to be activated by addition of the Tgf-beta family member Bmp-4. To determine if Bmp-4 could activate Msx-3, we incubated embryonic hindbrain explants with exogenous Bmp-4. The dorsal expression of Msx-3 was seen to expand into more ventral regions of the neurectoderm in Bmp-4-treated cultures, implying that Bmp-4 may be able to mimic an in vivo signal that induces Msx-3.

SoxB1-driven transcriptional network underlies neural-specific interpretation of morphogen signals.

PubMed

Oosterveen, Tony; Kurdija, Sanja; Ensterö, Mats; Uhde, Christopher W; Bergsland, Maria; Sandberg, Magnus; Sandberg, Rickard; Muhr, Jonas; Ericson, Johan

2013-04-30

The reiterative deployment of a small cadre of morphogen signals underlies patterning and growth of most tissues during embyogenesis, but how such inductive events result in tissue-specific responses remains poorly understood. By characterizing cis-regulatory modules (CRMs) associated with genes regulated by Sonic hedgehog (Shh), retinoids, or bone morphogenetic proteins in the CNS, we provide evidence that the neural-specific interpretation of morphogen signaling reflects a direct integration of these pathways with SoxB1 proteins at the CRM level. Moreover, expression of SoxB1 proteins in the limb bud confers on mesodermal cells the potential to activate neural-specific target genes upon Shh, retinoid, or bone morphogenetic protein signaling, and the collocation of binding sites for SoxB1 and morphogen-mediatory transcription factors in CRMs faithfully predicts neural-specific gene activity. Thus, an unexpectedly simple transcriptional paradigm appears to conceptually explain the neural-specific interpretation of pleiotropic signaling during vertebrate development. Importantly, genes induced in a SoxB1-dependent manner appear to constitute repressive gene regulatory networks that are directly interlinked at the CRM level to constrain the regional expression of patterning genes. Accordingly, not only does the topology of SoxB1-driven gene regulatory networks provide a tissue-specific mode of gene activation, but it also determines the spatial expression pattern of target genes within the developing neural tube.

Selected Plant Metabolites Involved in Oxidation-Reduction Processes during Bud Dormancy and Ontogenetic Development in Sweet Cherry Buds (Prunus avium L.).

PubMed

Baldermann, Susanne; Homann, Thomas; Neugart, Susanne; Chmielewski, Frank-M; Götz, Klaus-Peter; Gödeke, Kristin; Huschek, Gerd; Morlock, Getrud E; Rawel, Harshadrai M

2018-05-17

Many biochemical processes are involved in regulating the consecutive transition of different phases of dormancy in sweet cherry buds. An evaluation based on a metabolic approach has, as yet, only been partly addressed. The aim of this work, therefore, was to determine which plant metabolites could serve as biomarkers for the different transitions in sweet cherry buds. The focus here was on those metabolites involved in oxidation-reduction processes during bud dormancy, as determined by targeted and untargeted mass spectrometry-based methods. The metabolites addressed included phenolic compounds, ascorbate/dehydroascorbate, reducing sugars, carotenoids and chlorophylls. The results demonstrate that the content of phenolic compounds decrease until the end of endodormancy. After a long period of constancy until the end of ecodormancy, a final phase of further decrease followed up to the phenophase open cluster. The main phenolic compounds were caffeoylquinic acids, coumaroylquinic acids and catechins, as well as quercetin and kaempferol derivatives. The data also support the protective role of ascorbate and glutathione in the para- and endodormancy phases. Consistent trends in the content of reducing sugars can be elucidated for the different phenophases of dormancy, too. The untargeted approach with principle component analysis (PCA) clearly differentiates the different timings of dormancy giving further valuable information.

The tumor microenvironment: An irreplaceable element of tumor budding and epithelial-mesenchymal transition-mediated cancer metastasis

PubMed Central

Li, Hui; Xu, Fangying; Li, Si; Zhong, Anjing; Meng, Xianwen; Lai, Maode

2016-01-01

ABSTRACT Tumor budding occurs at the invasive front of cancer; the tumor cells involved have metastatic and stemness features, indicating a poor prognosis. Tumor budding is partly responsible for cancer metastasis, and its initiation is based on the epithelial-mesenchymal transition (EMT) process. The EMT process involves the conversion of epithelial cells into migratory and invasive cells, and is a profound event in tumorigenesis. The EMT, associated with the formation of cancer stem cells (CSCs) and resistance to therapy, results from a combination of gene mutation, epigenetic regulation, and microenvironmental control. Tumor budding can be taken to represent the EMT in vivo. The EMT process is under the influence of the tumor microenvironment as well as tumor cells themselves. Here, we demonstrate that the tumor microenvironment dominates EMT development and impacts cancer metastasis, as well as promotes CSC formation and mediates drug resistance. In this review, we mainly discuss components of the microenvironment, such as the extracellular matrix (ECM), inflammatory cytokines, metabolic products, and hypoxia, that are involved in and impact on the acquisition of tumor-cell motility and dissemination, the EMT, metastatic tumor-cell formation, tumor budding and CSCs, and cancer metastasis, including subsequent chemo-resistance. From our point of view, the tumor microenvironment now constitutes a promising target for cancer therapy. PMID:26743180

Micropropagation of Phalaenopsis and Doritaenopsis by culturing shoot tips of flower stalk buds.

PubMed

Tokuhara, K; Mii, M

1993-11-01

Green Protocorm-like Bodies (PLB) with high multiplication capacity were induced from shoot tips of flower stalk buds having 1 or 2 leaf primordia using New Dogashima Medium (NDM) containing 0.1 mg l(-1) α-naphthaleneacetic acid (NAA) and 1 mg 1(-1) 6-benzylaminopurine (BAP). These PLB were subcultured on the same medium. More than 10,000 PLBs were obtained from a few buds on a single flower stalk within one year. After transfer onto NDM containing no plant growth regulator (PGR), the PLB developed into plantlets. The micropropagation method formulated in this study was applicable to 12 different genotypes. These results suggest that the methodology could be used on a commercial scale for vegetative propagation of Phalaenopsis and Doritaenopsis.

Model of human immunodeficiency virus budding and self-assembly: Role of the cell membrane

NASA Astrophysics Data System (ADS)

Zhang, Rui; Nguyen, Toan T.

2008-11-01

Budding from the plasma membrane of the host cell is an indispensable step in the life cycle of the human immunodeficiency virus (HIV), which belongs to a large family of enveloped RNA viruses, retroviruses. Unlike regular enveloped viruses, retrovirus budding happens concurrently with the self-assembly of the main retrovirus protein subunits (called Gag protein after the name of the genetic material that codes for this protein: Group-specific AntiGen) into spherical virus capsids on the cell membrane. Led by this unique budding and assembly mechanism, we study the free energy profile of retrovirus budding, taking into account the Gag-Gag attraction energy and the membrane elastic energy. We find that if the Gag-Gag attraction is strong, budding always proceeds to completion. During early stage of budding, the zenith angle of partial budded capsids, α , increases with time as α∝t1/2 . However, if the Gag-Gag attraction is weak, a metastable state of partial budding appears. The zenith angle of these partially spherical capsids is given by α0≃(τ2/κσ)1/4 in a linear approximation, where κ and σ are the bending modulus and the surface tension of the membrane, and τ is a line tension of the capsid proportional to the strength of Gag-Gag attraction. Numerically, we find α0<0.3π without any approximations. Using experimental parameters, we show that HIV budding and assembly always proceed to completion in normal biological conditions. On the other hand, by changing Gag-Gag interaction strength or membrane rigidity, it is relatively easy to tune it back and forth between complete budding and partial budding. Our model agrees reasonably well with experiments observing partial budding of retroviruses including HIV.

Chronic Oral Capsaicin Exposure During Development Leads to Adult Rats with Reduced Taste Bud Volumes.

PubMed

Omelian, Jacquelyn M; Samson, Kaeli K; Sollars, Suzanne I

2016-09-01

Cross-sensory interaction between gustatory and trigeminal nerves occurs in the anterior tongue. Surgical manipulations have demonstrated that the strength of this relationship varies across development. Capsaicin is a neurotoxin that affects fibers of the somatosensory lingual nerve surrounding taste buds, but not fibers of the gustatory chorda tympani nerve which synapse with taste receptor cells. Since capsaicin is commonly consumed by many species, including humans, experimental use of this neurotoxin provides a naturalistic perturbation of the lingual trigeminal system. Neonatal or adults rats consumed oral capsaicin for 40 days and we examined the cross-sensory effect on the morphology of taste buds across development. Rats received moderate doses of oral capsaicin, with chronic treatments occurring either before or after taste system maturation. Tongue morphology was examined either 2 or 50 days after treatment cessation. Edema, which has been previously suggested as a cause of changes in capsaicin-related gustatory function, was also assessed. Reductions in taste bud volume occurred 50 days, but not 2 days post-treatment for rats treated as neonates. Adult rats at either time post-treatment were unaffected. Edema was not found to occur with the 5 ppm concentration of capsaicin we used. Results further elucidate the cooperative relationship between these discrete sensory systems and highlight the developmentally mediated aspect of this interaction. Chronic exposure to even moderate levels of noxious stimuli during development has the ability to impact the orosensory environment, and these changes may not be evident until long after exposure has ceased.

Pharmacognostic Specification, Chlorogenic Acid Content, and In vitro Antioxidant Activities of Lonicera japonica Flowering Bud

PubMed Central

Chaowuttikul, Chayanon; Palanuvej, Chanida; Ruangrungsi, Nijsiri

2017-01-01

Background: Lonicera japonica Thunb. or Japanese Honeysuckle has been widely used in traditional medicine for antipyretic. Objective: To establish the pharmacognostic specification of L. japonica flowering bud in Thailand and to determine its chlorogenic acid content and in vitro antioxidant activities. Materials and Methods: Dried L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were investigated for pharmacognostic specification. Their chlorogenic acid contents were quantitatively analyzed by thin layer chromatography (TLC) densitometry with winCATS software. The mobile phase for TLC development consisted of ethyl acetate: formic acid: acetic acid: water (10:1.1:1.1:2.6). Antioxidant activities were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power assay, nitric oxide scavenging assay, and β-carotene bleaching assays. Results: Qualified L. japonica flowering bud in Thailand was presented that the contents of loss on drying, total ash, acid-insoluble ash, and water should not be >10.11%, 6.59%, 1.14%, and 10.82% by weight, respectively. The ethanol and water soluble extractive values should not be < 16.46% and 28.88% by weight, respectively. Chlorogenic acid content in L. japonica flowering bud was found to be 2.24 ± 0.50 g/100 g of crude drug. L. japonica flowering bud showed DPPH and nitric oxide scavenging activities as well as reducing power property. Conclusion: This pharmacognostic specification with special reference to the chlorogenic acid content can be used for quality control of L. japonica flowering bud in Thailand. The potential antioxidant of this crude drug was demonstrated in vitro. SUMMARY Pharmacognostic specification of Lonicera japonica flowering bud in Thailand has been establishedThe chlorogenic acid content has been quantified by thin layer chromatography-densitometryThe ethanolic extract of L. japonica flowering bud showed antioxidation potential, especially on reducing power property. Abbreviations Used: TLC: Thin layer chromatography, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FRAP: Ferric ion Reducing Antioxidant Power, WHO: World Health Organization, ICH: International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; LOD: Limit of detection; LOQ: Limit of quantitation; BHT: Butylated hydroxytoluene; FeSO4: Iron(II) sulfate; DMSO: Dimethyl sulfoxide; TPTZ: 2,4,6-tripyridyl-s-triazine. PMID:28539735

Lipopolysaccharide-induced inflammation attenuates taste progenitor cell proliferation and shortens the life span of taste bud cells.

PubMed

Cohn, Zachary J; Kim, Agnes; Huang, Liquan; Brand, Joseph; Wang, Hong

2010-06-10

The mammalian taste bud, a complex collection of taste sensory cells, supporting cells, and immature basal cells, is the structural unit for detecting taste stimuli in the oral cavity. Even though the cells of the taste bud undergo constant turnover, the structural homeostasis of the bud is maintained by balancing cell proliferation and cell death. Compared with nongustatory lingual epithelial cells, taste cells express higher levels of several inflammatory receptors and signalling proteins. Whether inflammation, an underlying condition in some diseases associated with taste disorders, interferes with taste cell renewal and turnover is unknown. Here we report the effects of lipopolysaccharide (LPS)-induced inflammation on taste progenitor cell proliferation and taste bud cell turnover in mouse taste tissues. Intraperitoneal injection of LPS rapidly induced expression of several inflammatory cytokines, including tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-6, in mouse circumvallate and foliate papillae. TNF-alpha and IFN-gamma immunoreactivities were preferentially localized to subsets of cells in taste buds. LPS-induced inflammation significantly reduced the number of 5-bromo-2'-deoxyuridine (BrdU)-labeled newborn taste bud cells 1-3 days after LPS injection, suggesting an inhibition of taste bud cell renewal. BrdU pulse-chase experiments showed that BrdU-labeled taste cells had a shorter average life span in LPS-treated mice than in controls. To investigate whether LPS inhibits taste cell renewal by suppressing taste progenitor cell proliferation, we studied the expression of Ki67, a cell proliferation marker. Quantitative real-time RT-PCR revealed that LPS markedly reduced Ki67 mRNA levels in circumvallate and foliate epithelia. Immunofluorescent staining using anti-Ki67 antibodies showed that LPS decreased the number of Ki67-positive cells in the basal regions surrounding circumvallate taste buds, the niche for taste progenitor cells. PCR array experiments showed that the expression of cyclin B2 and E2F1, two key cell cycle regulators, was markedly downregulated by LPS in the circumvallate and foliate epithelia. Our results show that LPS-induced inflammation inhibits taste progenitor cell proliferation and interferes with taste cell renewal. LPS accelerates cell turnover and modestly shortens the average life span of taste cells. These effects of inflammation may contribute to the development of taste disorders associated with infections.

Effects of zinc deficiency on the vallate papillae and taste buds in rats.

PubMed

Chou, H C; Chien, C L; Huang, H L; Lu, K S

2001-05-01

Zinc deficiency is associated with multiple clinical complications, including taste disturbance, anorexia, growth retardation, skin changes, and hypogonadism. We investigated the zinc-deficiency-induced morphologic changes in the vallate taste buds of weanling and young adult male Wistar rats. A total of 24 weanling and 30 young adult rats were used. Each age group was further divided into a control group fed a zinc-adequate (50 ppm) diet, a zinc-deficient (< 1 ppm) diet group, and a zinc-adequate pair-fed group who were fed the same amount of food as that taken by the zinc-deficient group. Weanling rats were fed for 4 weeks and young adult rats were fed for 6 weeks. The morphometry and morphologic changes of vallate taste buds were analyzed using light and transmission electron microscopy. Light microscopy revealed no significant difference in papilla size and morphology among the various groups. In both weanling and young adult rats in the zinc-deficient diet and pair-fed groups, the number of taste buds per papilla (per animal) and the average profile area of the taste bud were significantly smaller than those of the corresponding controls (p < 0.05). Ultrastructural changes were seen only in the taste buds of weanling rats fed the zinc-deficient diet, with derangement of the architecture of the taste bud and widening of the intercellular space between taste bud cells. The proportion of type I taste bud cells in the taste buds of weanling rats fed the zinc-deficient diet decreased from 59% to 39%, and that of type II taste bud cells decreased from 25% to 12%. No obvious changes in the ultrastructure of type III taste bud cells were observed. The main effects of zinc deficiency in weanling and young adult rats and in adequate diet pair-fed rats were changes in the number and size of taste buds, and fine structure changes in the taste bud cells, especially during the accelerated growth stage after weaning.

In vitro propagation of persimmon (Diospyros kaki Thunb.).

PubMed

Giordani, Edgardo; Naval, Mar; Benelli, Carla

2013-01-01

Persimmon (Diospyros kaki Thunb.) is a temperate fruit tree species diffused in all continents. The traditional propagation method adopted by the nursery industry is based on budding/grafting scion cultivars on seedlings from D. kaki, Diospyros lotus, and Diospyros virginiana, the most important species used as rootstock, reproduced by seeds since they are not easy to root. Furthermore, most of nonastringent cultivars of persimmon are not compatible with D. lotus, a rootstock largely utilized because of its hardiness and frost resistance. The main in vitro tissue culture techniques, developed for persimmon, deal with direct regeneration (from dormant buds and root tips), and indirect regeneration through callus from dormant buds, apexes, and leaves. The bottlenecks of micropropagation are (1) the recalcitrance of many cultivars to in vitro establishment, (2) the low multiplication ratio of D. kaki compared to other fruit tree species, (3) the very low rooting ability of ex novo microcuttings both from direct and indirect regeneration, (4) the high sensitivity to transplant from in vitro to in vivo conditions. The development of reliable in vitro regeneration procedures is likely to play a key role for production of both clonal rootstocks and self-rooted cultivars. The general protocol for micropropagation of persimmon reported here is based on the establishment of winter dormant buds in vitro, shoot development, multiplication and elongation, and shoot rooting, using cytokinins (BA or zeatin) in a MS media along with an auxinic pretreatment for rooting induction.

Dact2 is expressed in the developing ureteric bud/collecting duct system of the kidney and controls morphogenetic behavior of collecting duct cells.

PubMed

Lee, Wen-Chin; Hough, Melinda T; Liu, Weijia; Ekiert, Robert; Lindström, Nils O; Hohenstein, Peter; Davies, Jamie A

2010-10-01

The overall pattern of the developing kidney is set in large part by the developing ureteric bud/collecting duct system, and dysgenesis of this system accounts for a variety of clinically significant renal diseases. Understanding how the behavior of cells in the developing ureteric bud/collecting duct is controlled is therefore important to understanding the normal and abnormal kidney. Dact proteins have recently been identified as cytoplasmic regulators of intracellular signaling. Dact1 inhibits Wnt signaling, and Dact2 inhibits transforming growth factor (TGF)-β signaling. Here, we report that Dact2 is expressed in developing and adult mouse kidneys, specifically in the ureteric bud/collecting duct epithelium, a structure whose morphogenesis is controlled partially by TGF-β. When small interfering RNA is used to knock down Dact2 expression in collecting duct cells, they show some constitutive phospho-Smad2, undetectable in controls, and elevated phospho-Smad2 in response to TGF-β. They also show defective migration and, in a monolayer wound-healing assay, they fail to assemble a leading edge "cable" of actomyosin and advance instead as a disorganized mass of lamellipodium-bearing cells. This effect is seriously exacerbated by exogenous TGF-β, although control cells tolerate it well. In three-dimensional culture, Dact2 knockdown cells form cysts and branching tubules, but the outlines of the cysts made by knockdown cells are ragged rather than smooth and the branching tubules are decorated with many fine spikes not seen in controls. These data suggest Dact2 plays a role in regulating morphogenesis by renal collecting duct cells, probably by protecting cells from overly strong TGF-β pathway activation.

Environmental control of branching in petunia.

PubMed

Drummond, Revel S M; Janssen, Bart J; Luo, Zhiwei; Oplaat, Carla; Ledger, Susan E; Wohlers, Mark W; Snowden, Kimberley C

2015-06-01

Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal. © 2015 American Society of Plant Biologists. All Rights Reserved.

Environmental Control of Branching in Petunia1[OPEN

PubMed Central

Oplaat, Carla; Wohlers, Mark W.

2015-01-01

Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal. PMID:25911529

RACK1 regulates mesenchymal cell recruitment during sexual and asexual reproduction of budding tunicates.

PubMed

Tatzuke, Yuki; Sunanaga, Takeshi; Fujiwara, Shigeki; Kawamura, Kaz

2012-08-15

A homolog of receptor for activated protein kinase C1 (RACK1) was cloned from the budding tunicate Polyandrocarpa misakiensis. By RT-PCR and in situ hybridization analyses, PmRACK1 showed biphasic gene expression during asexual and sexual reproduction. In developing buds, the signal was exclusively observed in the multipotent atrial epithelium and undifferentiated mesenchymal cells that contributed to morphogenesis by the mesenchymal-epithelial transition (MET). In juvenile zooids, the signal was first observable in germline precursor cells that arose as mesenchymal cell aggregated in the ventral hemocoel. In mature zooids, the germinal epithelium in the ovary and the pharynx were the most heavily stained parts. GFP reporter assay indicated that the ovarian expression of PmRACK1 was constitutive from germline precursor cells to oocytes. To elucidate the in vivo function of PmRACK1, RNA interference was challenged. When growing buds were incubated with 5 nmol/mL siRNA, most mesenchymal cells remained round and appeared to have no interactions with the extracellular matrix (ECM), causing lower activity of MET without any apparent effects on cell proliferation. The resultant zooids became growth-deficient. The dwarf zooids did not form buds or mature gonads. Prior to RNAi, buds were treated with human BMP4 that could induce PmRACK1 expression, which resulted in MET activity. We conclude that in P. misakiensis, PmRACK1 plays roles in mesenchymal cell recruitment during formation of somatic and gonad tissues, which contributes to zooidal growth and sexual and asexual reproduction. Copyright © 2012 Elsevier Inc. All rights reserved.

The ratio of red light to far red light alters Arabidopsis axillary bud growth and abscisic acid signalling before stem auxin changes.

PubMed

Holalu, Srinidhi V; Finlayson, Scott A

2017-02-01

Arabidopsis thaliana shoot branching is inhibited by a low red light to far red light ratio (R:FR, an indicator of competition), and by loss of phytochrome B function. Prior studies have shown that phytochrome B deficiency suppresses bud growth by elevating systemic auxin signalling, and that increasing the R:FR promotes the growth of buds suppressed by low R:FR by inhibiting bud abscisic acid (ABA) accumulation and signalling. Here, systemic auxin signalling and bud ABA signalling were examined in the context of rapid bud responses to an increased R:FR. Increasing the R:FR promoted the growth of buds inhibited by a low R:FR within 6 h. Relative to a low R:FR, bud ABA accumulation and signalling in plants given a high R:FR showed a sustained decline within 3 h, prior to increased growth. Main stem auxin levels and signalling showed a weak, transient response. Systemic effects and those localised to the bud were further examined by decapitating plants maintained either under a low R:FR or provided with a high R:FR. Increasing the R:FR promoted bud growth before decapitation, but decapitated plants eventually formed longer branches. The data suggest that rapid responses to an increased R:FR may be mediated by changes in bud ABA physiology, although systemic auxin signalling is necessary for sustained bud repression under a low R:FR. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

A Fate Map of the Murine Pancreas Buds Reveals a Multipotent Ventral Foregut Organ Progenitor

PubMed Central

Angelo, Jesse R.; Guerrero-Zayas, Mara-Isel; Tremblay, Kimberly D.

2012-01-01

The definitive endoderm is the embryonic germ layer that gives rise to the budding endodermal organs including the thyroid, lung, liver and pancreas as well as the remainder of the gut tube. DiI fate mapping and whole embryo culture were used to determine the endodermal origin of the 9.5 days post coitum (dpc) dorsal and ventral pancreas buds. Our results demonstrate that the progenitors of each bud occupy distinct endodermal territories. Dorsal bud progenitors are located in the medial endoderm overlying somites 2–4 between the 2 and 11 somite stage (SS). The endoderm forming the ventral pancreas bud is found in 2 distinct regions. One territory originates from the left and right lateral endoderm caudal to the anterior intestinal portal by the 6 SS and the second domain is derived from the ventral midline of the endoderm lip (VMEL). Unlike the laterally located ventral foregut progenitors, the VMEL population harbors a multipotent progenitor that contributes to the thyroid bud, the rostral cap of the liver bud, ventral midline of the liver bud and the midline of the ventral pancreas bud in a temporally restricted manner. This data suggests that the midline of the 9.5 dpc thyroid, liver and ventral pancreas buds originates from the same progenitor population, demonstrating a developmental link between all three ventral foregut buds. Taken together, these data define the location of the dorsal and ventral pancreas progenitors in the prespecified endodermal sheet and should lead to insights into the inductive events required for pancreas specification. PMID:22815796

An elastic model of partial budding of retroviruses

NASA Astrophysics Data System (ADS)

Zhang, Rui; Nguyen, Toan

2008-03-01

Retroviruses are characterized by their unique infection strategy of reverse transcription, in which the genetic information flows from RNA back to DNA. The most well known representative is the human immunodeficiency virus (HIV). Unlike budding of traditional enveloped viruses, retrovirus budding happens together with the formation of spherical virus capsids at the cell membrane. Led by this unique budding mechanism, we proposed an elastic model of retrovirus budding in this work. We found that if the lipid molecules of the membrane are supplied fast enough from the cell interior, the budding always proceeds to completion. In the opposite limit, there is an optimal size of partially budded virions. The zenith angle of these partially spherical capsids, α, is given by α˜(2̂/κσ)^1/4, where κ is the bending modulus of the membrane, σ is the surface tension of the membrane, and τ characterizes the strength of capsid protein interaction. If τ is large enough such that α˜π, the budding is complete. Our model explained many features of retrovirus partial budding observed in experiments.

Detection of genes regulated by Lmx1b during limb dorsalization.

PubMed

Feenstra, Jennifer M; Kanaya, Kohei; Pira, Charmaine U; Hoffman, Sarah E; Eppey, Richard J; Oberg, Kerby C

2012-05-01

Lmx1b is a homeodomain transcription factor that regulates dorsal identity during limb development. Lmx1b knockout (KO) mice develop distal ventral-ventral limbs. Although induction of Lmx1b is linked to Wnt7a expression in the dorsal limb ectoderm, the downstream targets of Lmx1b that accomplish limb dorsalization are unknown. To identify genes targeted by Lmx1b, we compared gene arrays from Lmx1b KO and wild type mouse limbs during limb dorsalization, i.e., 11.5, 12.5, and 13.5 days post coitum. We identified 54 target genes that were differentially expressed in all three stages. Several skeletal targets, including Emx2, Matrilin1 and Matrilin4, demonstrated a loss of scapular expression in the Lmx1b KO mice, supporting a role for Lmx1b in scapula development. Furthermore, the relative abundance of extracellular matrix-related soft tissue targets regulated by Lmx1b, such as collagens and proteoglycans, suggests a mechanism that includes changes in the extracellular matrix composition to accomplish limb dorsalization. Our study provides the most comprehensive characterization of genes regulated by Lmx1b during limb development to-date and provides targets for further investigation. © 2012 The Authors. Development, Growth & Differentiation © 2012 Japanese Society of Developmental Biologists.

Immunohistochemical study of Ki67, CD34 and p53 expression in human tooth buds.

PubMed

Muica Nagy-Bota, Monica Cristina; Pap, Zsuzsanna; Denes, Lóránd; Ghizdavăţ, Alexandru; Brînzaniuc, Klara; Lup Coşarcă, Adina Simona; Chibelean Cireş-Mărginean, Manuela; Păcurar, Mariana; Pávai, Zoltán

2014-01-01

Establishment of Ki67, p53 and CD34 expression in human tooth buds of different stages of odontogenetic development. Tissue samples containing tooth buds were removed from the incisor areas of human fetuses in different stages of development (weeks 9-10, 12-13, 13-16, 21-24), and from the canine and molar areas of 21-24 weeks fetuses. The tissue fragments were fixed using formalin and were processed using common histological techniques with paraffin embedding. Immunostaining for Ki67, p53 and CD34 has been performed using the dextran method and moist heat antigen retrieval (except for CD34). The resulting slides were photographed and quantitatively evaluated. Ki67 immunoexpression decreases with advancement of the developmental stage of the tooth bud: in the inner enamel epithelium, between weeks 9 and 16 (IEE), in the preameloblasts (PB) between weeks 13 and 16, in the ameloblasts (AB) between weeks 21 and 24; outer enamel epithelium (OEE); stratum intermedium (SI); in the dental papilla: between weeks 9 and 10 in the dental papilla (DP), between weeks 13 and 16 in the outer layer of the dental papilla (DP1) and in the central layer of the dental papilla (DP2). Likewise, we noted Ki67 expression in the odontoblast layer (O) and pulp (P), between weeks 21 and 24. Concerning CD34 expression, we observed a decrease from weeks 9-10 until weeks 13-16, followed by an increase until weeks 21-24 of intrauterine life. From weeks 9-10, we observed a constant decrease of expression until weeks 13-16, followed by an increase during weeks 21-24. All Ki67, p53 and CD34 have been identified in the tooth bud. Ki67 expression gradually decreases with the embryonic development of the tooth, while p53 and CD34 expression decreases from weeks 9-10 to weeks 13-16 of intrauterine life, followed by an increase until weeks 21-24.

Detection of Genes Regulated by Lmx1b During Limb Dorsalization

PubMed Central

Feenstra, Jennifer M.; Kanaya, Kohei; Pira, Charmaine U; Hoffman, Sarah E.; Eppey, Richard J.; Oberg, Kerby C.

2012-01-01

Lmx1b is a homeodomain transcription factor that regulates dorsal identity during limb development. Lmx1b knockout (KO) mice develop distal ventral-ventral limbs. Although induction of Lmx1b is linked to Wnt7a expression in the dorsal limb ectoderm, the downstream targets of Lmx1b that accomplish limb dorsalization are unknown. To identify genes targeted by Lmx1b, we compared gene arrays from Lmx1b KO and wildtype mouse limbs during limb dorsalization, i.e., 11.5, 12.5, and 13.5 days post coitum. We identified 54 target genes differentially expressed in all three stages. Several skeletal targets, including Emx2, Matrilin1 and Matrilin4, demonstrated a loss of scapular expression in the Lmx1b KO mice, supporting a role for Lmx1b in scapula development. Furthermore, the relative abundance of extracellular matrix-related soft tissue targets regulated by Lmx1b, such as collagens and proteoglycans, suggests a mechanism which includes changes in the extracellular matrix composition to accomplish limb dorsalization. Our study provides the most comprehensive characterization of genes regulated by Lmx1b during limb development to-date and provides targets for further investigation. PMID:22417325

Long-term Follow-up Results of Regeneration Process of Fungiform Taste Buds After Severing the Chorda Tympani Nerve During Middle Ear Surgery.

PubMed

Saito, Takehisa; Ito, Tetsufumi; Ito, Yumi; Manabe, Yasuhiro

2016-05-01

To elucidate the regeneration process of fungiform taste buds after severing the chorda tympani nerve (CTN) by confocal laser scanning microscopy in vivo. In 7 consecutive patients whose CTN was severed during tympanoplasty, an average of 10 fungiform papillae in the midlateral region of the tongue were periodically observed, and the number of taste buds was counted until 12 to 24 months after surgery. Gustatory function was assessed by EGM. EGM thresholds showed no response within 1 month after surgery in any patient. All taste buds had disappeared until 13 to 71 days after surgery. Regenerated taste buds were first detected 5 to 8 months after surgery in 5 of the 7 patients. EGM thresholds recovered to their preoperative values in 2 patients. In these 2 patients, the number of regenerated taste buds gradually increased in combination with a recovered taste function. However, a time lag existed between taste bud regeneration and taste function recovery. EGM thresholds did not recover in the other 3 patients with regenerated taste buds, suggesting that these taste buds were immature without gustatory function. The long-term regeneration process of fungiform taste buds could be clarified using confocal laser scanning microscopy. © The Author(s) 2015.

Analysis of the transcriptional responses in inflorescence buds of Jatropha curcas exposed to cytokinin treatment.

PubMed

Chen, Mao-Sheng; Pan, Bang-Zhen; Wang, Gui-Juan; Ni, Jun; Niu, Longjian; Xu, Zeng-Fu

2014-11-30

Jatropha curcas L. is a potential biofuel plant. Application of exogenous cytokinin (6-benzyladenine, BA) on its inflorescence buds can significantly increase the number of female flowers, thereby improving seed yield. To investigate which genes and signal pathways are involved in the response to cytokinin in J. curcas inflorescence buds, we monitored transcriptional activity in inflorescences at 0, 3, 12, 24, and 48 h after BA treatment using a microarray. We detected 5,555 differentially expressed transcripts over the course of the experiment, which could be grouped into 12 distinct temporal expression patterns. We also identified 31 and 131 transcripts in J. curcas whose homologs in model plants function in flowering and phytohormonal signaling pathways, respectively. According to the transcriptional analysis of genes involved in flower development, we hypothesized that BA treatment delays floral organ formation by inhibiting the transcription of the A, B and E classes of floral organ-identity genes, which would allow more time to generate more floral primordia in inflorescence meristems, thereby enhancing inflorescence branching and significantly increasing flower number per inflorescence. BA treatment might also play an important role in maintaining the flowering signals by activating the transcription of GIGANTEA (GI) and inactivating the transcription of CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) and TERMINAL FLOWER 1b (TFL1b). In addition, exogenous cytokinin treatment could regulate the expression of genes involved in the metabolism and signaling of other phytohormones, indicating that cytokinin and other phytohormones jointly regulate flower development in J. curcas inflorescence buds. Our study provides a framework to better understand the molecular mechanisms underlying changes in flowering traits in response to cytokinin treatment in J. curcas inflorescence buds. The results provide valuable information related to the mechanisms of cross-talk among multiple phytohormone signaling pathways in woody plants.

Actin cable dynamics in budding yeast

PubMed Central

Yang, Hyeong-Cheol; Pon, Liza A.

2002-01-01

Actin cables, bundles of actin filaments that align along the long axis of budding yeast, are crucial for establishment of cell polarity. We fused green fluorescent protein (GFP) to actin binding protein 140 (Abp140p) and visualized actin cable dynamics in living yeast. We detected two populations of actin cables: (i) bud-associated cables, which extend from the bud along the mother-bud axis, and (ii) randomly oriented cables, which are relatively short. Time-lapse imaging of Abp140p–GFP revealed an apparent increase in the length of bud-associated actin cables. Analysis of movement of Abp140p–GFP fiduciary marks on bud-associated cables and fluorescence loss in photobleaching experiments revealed that this apparent elongation occurs by assembly of new material at the end of the cable within the bud and movement of the opposite end of the cable toward the tip of the mother cell distal to the bud. The rate of extension of the tip of an elongating actin cable is 0.29 ± 0.08 μm/s. Latrunculin A (Lat-A) treatment completely blocked this process. We also observed movement of randomly oriented cables around the cortex of cells at a rate of 0.59 ± 0.14 μm/s. Mild treatment with Lat-A did not affect the velocity of movement of randomly oriented cables. However, Lat-A treatment did increase the number of randomly oriented, motile cables per cell. Our observations suggest that establishment of bud-associated actin cables during the cell cycle is accomplished not by realignment of existing cables but by assembly of new cables within the bud or bud neck, followed by elongation. PMID:11805329

BudBurst Buddies: Introducing Young Citizen Scientists to Plants and Environmental Change

NASA Astrophysics Data System (ADS)

Ward, D.; Gardiner, L. S.; Henderson, S.

2011-12-01

As part of Project BudBurst, the BudBurst Buddies recently moved to the National Ecological Network (NEON) as part of its Education and Public Engagement efforts. The BudBurst Buddies (www.budburstbuddies.org) were created to engage elementary school age children in the science of observing plants and the timing of phenological (life cycle) events. BudBurst Buddies is a part of the Project BudBurst national citizen science initiative (www.budburst.org), which allows individuals to engage in the scientific process, contributing to a better understanding of climate change while increasing public awareness of phenology and the impacts of climate change on plants. As a first step towards engaging the next generation of citizen scientists, BudBurst Buddies provides the opportunity for children to gain experience with scientific research and increases awareness of how plants change throughout the year. Hundreds of young students have participated in the inaugural year of BudBurst Buddies. Children can participate in BudBurst Buddies on their own, with their families, or in formal or informal education settings. The program was recently highlighted by education staff at the New York Hall of Science and numerous classrooms have been implementing this resource as part of their curriculum. Each child who participates creates a journal about a plant of his or her choosing, makes observations of the plant over the growing season and submits findings online, earning an official BudBurst Buddies certificate. An online storybook for kids tells how two children, Lily and Sage, observed plants in their neighborhood and became BudBurst Buddies. This presentation will provide an overview of the BudBurst Buddies resources including a new implementation guide and will also share feedback from the first year of implementation.

Mitochondrial anchorage and fusion contribute to mitochondrial inheritance and quality control in the budding yeast Saccharomyces cerevisiae.

PubMed

Higuchi-Sanabria, Ryo; Charalel, Joseph K; Viana, Matheus P; Garcia, Enrique J; Sing, Cierra N; Koenigsberg, Andrea; Swayne, Theresa C; Vevea, Jason D; Boldogh, Istvan R; Rafelski, Susanne M; Pon, Liza A

2016-03-01

Higher-functioning mitochondria that are more reduced and have less ROS are anchored in the yeast bud tip by the Dsl1-family protein Mmr1p. Here we report a role for mitochondrial fusion in bud-tip anchorage of mitochondria. Fluorescence loss in photobleaching (FLIP) and network analysis experiments revealed that mitochondria in large buds are a continuous reticulum that is physically distinct from mitochondria in mother cells. FLIP studies also showed that mitochondria that enter the bud can fuse with mitochondria that are anchored in the bud tip. In addition, loss of fusion and mitochondrial DNA (mtDNA) by deletion of mitochondrial outer or inner membrane fusion proteins (Fzo1p or Mgm1p) leads to decreased accumulation of mitochondria at the bud tip and inheritance of fitter mitochondria by buds compared with cells with no mtDNA. Conversely, increasing the accumulation and anchorage of mitochondria in the bud tip by overexpression of MMR1 results in inheritance of less-fit mitochondria by buds and decreased replicative lifespan and healthspan. Thus quantity and quality of mitochondrial inheritance are ensured by two opposing processes: bud-tip anchorage by mitochondrial fusion and Mmr1p, which favors bulk inheritance; and quality control mechanisms that promote segregation of fitter mitochondria to the bud. © 2016 Higuchi-Sanabria et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Genetic basis of climatic adaptation in scots pine by bayesian quantitative trait locus analysis.

PubMed Central

Hurme, P; Sillanpää, M J; Arjas, E; Repo, T; Savolainen, O

2000-01-01

We examined the genetic basis of large adaptive differences in timing of bud set and frost hardiness between natural populations of Scots pine. As a mapping population, we considered an "open-pollinated backcross" progeny by collecting seeds of a single F(1) tree (cross between trees from southern and northern Finland) growing in southern Finland. Due to the special features of the design (no marker information available on grandparents or the father), we applied a Bayesian quantitative trait locus (QTL) mapping method developed previously for outcrossed offspring. We found four potential QTL for timing of bud set and seven for frost hardiness. Bayesian analyses detected more QTL than ANOVA for frost hardiness, but the opposite was true for bud set. These QTL included alleles with rather large effects, and additionally smaller QTL were supported. The largest QTL for bud set date accounted for about a fourth of the mean difference between populations. Thus, natural selection during adaptation has resulted in selection of at least some alleles of rather large effect. PMID:11063704

Massive and Reproducible Production of Liver Buds Entirely from Human Pluripotent Stem Cells.

PubMed

Takebe, Takanori; Sekine, Keisuke; Kimura, Masaki; Yoshizawa, Emi; Ayano, Satoru; Koido, Masaru; Funayama, Shizuka; Nakanishi, Noriko; Hisai, Tomoko; Kobayashi, Tatsuya; Kasai, Toshiharu; Kitada, Rina; Mori, Akira; Ayabe, Hiroaki; Ejiri, Yoko; Amimoto, Naoki; Yamazaki, Yosuke; Ogawa, Shimpei; Ishikawa, Momotaro; Kiyota, Yasujiro; Sato, Yasuhiko; Nozawa, Kohei; Okamoto, Satoshi; Ueno, Yasuharu; Taniguchi, Hideki

2017-12-05

Organoid technology provides a revolutionary paradigm toward therapy but has yet to be applied in humans, mainly because of reproducibility and scalability challenges. Here, we overcome these limitations by evolving a scalable organ bud production platform entirely from human induced pluripotent stem cells (iPSC). By conducting massive "reverse" screen experiments, we identified three progenitor populations that can effectively generate liver buds in a highly reproducible manner: hepatic endoderm, endothelium, and septum mesenchyme. Furthermore, we achieved human scalability by developing an omni-well-array culture platform for mass producing homogeneous and miniaturized liver buds on a clinically relevant large scale (>10 8 ). Vascularized and functional liver tissues generated entirely from iPSCs significantly improved subsequent hepatic functionalization potentiated by stage-matched developmental progenitor interactions, enabling functional rescue against acute liver failure via transplantation. Overall, our study provides a stringent manufacturing platform for multicellular organoid supply, thus facilitating clinical and pharmaceutical applications especially for the treatment of liver diseases through multi-industrial collaborations. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

An efficient in vitro regeneration protocol for a natural dye yielding plant, Strobilanthes flaccidifolious Nees., from nodal explants.

PubMed

Deb, Chitta Ranjan; Arenmongla, T

2012-11-01

Adventitious shoot buds formation from axillary buds of nodal segments of S. flaccidifolious was achieved on MS medium containing sucrose (3%, w/v), and a-naphthalene acetic acid (NAA; 3 microM) and benzyl adenine (3 microM) in combination. The nodal segments were primed on 'Growtak Sieve' for 48 h on MS medium containing sucrose (2%), polyvinyl pyrollidone (200 mgL(-1)) as antioxidant. About 80% of primed nodal segments responded positively and formed approximately 12 adventitious shoot buds per explants from explants collected during October-November months of every year. The shoot buds converted into plantlets on MS medium containing sucrose (3%) and kinetin (3 microM) where approximately 7 micro shoots developed per subculture after 8 weeks of culture. The regenerated micro shoots induced average 14 roots/plant on medium containing NAA (3 microM). The regenerates were hardened for 6-7 weeks on medium with 1/2MS salt solution and sucrose (2%) under normal laboratory condition before transferring to potting mix. About 70% transplants survived after two months of transfer.

[Genome-wide identification and expression analysis of auxin-related gene families in grape].

PubMed

Yuan, Hua-zhao; Zhao, Mi-zhen; Wu, Wei-min; Yu, Hong-Mei; Qian, Ya-ming; Wang, Zhuang-wei; Wang, Xi-cheng

2015-07-01

The auxin response gene family adjusts the auxin balance and the growth hormone signaling pathways in plants. Using bioinformatics methods, the auxin-response genes from the grape genome database are identified and their chromosomal location, gene collinearity and phylogenetic analysis are performed. Probable genes include 25 AUX_IAA, 19 ARF, 9 GH3 and 42 LBD genes, which are unevenly distributed on all 19 chromosomes and some of them formed distinct tandem duplicate gene clusters. The available grape microarray databases show that all of the auxin-response genes are expressed in fruit and leaf buds, and significant overexpressed during fruit color-changing, bud break and bud dormancy periods. This paper provides a resource for functional studies of auxin-response genes in grape leaf and fruit development.

Tyrosine kinase receptor B (TrkB) expression in colorectal cancers highlights anoikis resistance as a survival mechanism of tumour budding cells.

PubMed

Dawson, Heather; Grundmann, Sandra; Koelzer, Viktor H; Galván, José A; Kirsch, Richard; Karamitopoulou, Eva; Lugli, Alessandro; Inderbitzin, Daniel; Zlobec, Inti

2015-04-01

Tumour buds in colorectal cancer represent an aggressive subgroup of non-proliferating and non-apoptotic tumour cells. We hypothesize that the survival of tumour buds is dependent upon anoikis resistance. The role of tyrosine kinase receptor B (TrkB), a promoter of epithelial-mesenchymal transition and anoikis resistance, in facilitating budding was investigated. Tyrosine kinase receptor B immunohistochemistry was performed on a multiple-punch tissue microarray of 211 colorectal cancer resections. Membranous/cytoplasmic and nuclear expression was evaluated in tumour and buds. Tumour budding was assessed on corresponding whole tissue slides. Relationship to Ki-67 and caspase-3 was investigated. Analysis of Kirsten Ras (KRAS), proto-oncogene B-RAF (BRAF) and cytosine-phosphate-guanosine island methylator phenotype (CIMP) was performed. Membranous/cytoplasmic and nuclear TrkB were strongly, inversely correlated (P < 0.0001; r = -0.41). Membranous/cytoplasmic TrkB was overexpressed in buds compared to the main tumour body (P < 0.0001), associated with larger tumours (P = 0.0236), high-grade budding (P = 0.0011) and KRAS mutation (P = 0.0008). Nuclear TrkB was absent in buds (P <0.0001) and in high-grade budding cancers (P =0.0073). Among patients with membranous/cytoplasmic TrkB-positive buds, high tumour membranous/cytoplasmic TrkB expression was a significant, independent adverse prognostic factor [P = 0.033; 1.79, 95% confidence interval (CI) 1.05-3.05]. Inverse correlations between membranous/cytoplasmic TrkB and Ki-67 (r = -0.41; P < 0.0001) and caspase-3 (r =-0.19; P < 0.05) were observed. Membranous/cytoplasmic TrkB may promote an epithelial-mesenchymal transition (EMT)-like phenotype with high-grade budding and maintain viability of buds themselves. © 2014 John Wiley & Sons Ltd.

Auxin flow-mediated competition between axillary buds to restore apical dominance

PubMed Central

Balla, Jozef; Medveďová, Zuzana; Kalousek, Petr; Matiješčuková, Natálie; Friml, Jiří; Reinöhl, Vilém; Procházka, Stanislav

2016-01-01

Apical dominance is one of the fundamental developmental phenomena in plant biology, which determines the overall architecture of aerial plant parts. Here we show apex decapitation activated competition for dominance in adjacent upper and lower axillary buds. A two-nodal-bud pea (Pisum sativum L.) was used as a model system to monitor and assess auxin flow, auxin transport channels, and dormancy and initiation status of axillary buds. Auxin flow was manipulated by lateral stem wounds or chemically by auxin efflux inhibitors 2,3,5-triiodobenzoic acid (TIBA), 1-N-naphtylphtalamic acid (NPA), or protein synthesis inhibitor cycloheximide (CHX) treatments, which served to interfere with axillary bud competition. Redirecting auxin flow to different points influenced which bud formed the outgrowing and dominant shoot. The obtained results proved that competition between upper and lower axillary buds as secondary auxin sources is based on the same auxin canalization principle that operates between the shoot apex and axillary bud. PMID:27824063

Temperatures during flower bud development affect pollen germination, self-incompatibility reaction and early fruit development of clementine (Citrus clementina Hort. ex Tan.).

PubMed

Distefano, G; Gentile, A; Hedhly, A; La Malfa, S

2018-03-01

One of the key environmental factors affecting plant reproductive systems is temperature. Characterising such effects is especially relevant for some commercially important genera such as Citrus. In this genus, failure of fertilisation results in parthenocarpic fruit development and seedlessness, which is a much-prized character. Here, we characterise the effects of temperature on flower and ovary development, and on pollen-pistil interactions in 'Comune' clementine (Citrus clementina Hort. ex Tan.). We examine flower bud development, in vitro pollen germination and pollen-pistil interaction at different temperatures (15, 20, 25 or 30 °C). These temperatures span the range from 'cold' to 'hot' weather during the flowering season in many citrus-growing regions. Temperature had a strong effect on flower and ovary development, pollen germination, and pollen tube growth kinetics. In particular, parthenocarpic fruit development (indicated by juice vesicle growth) was initiated early if flowers were exposed to warmer temperatures during anthesis. Exposure to different temperatures during flower bud development also alters expression of the self-incompatibility reaction. This affects the point in the pistil at which pollen tube growth is arrested and confirms the role of sub- and supra-optimal temperatures in determining the numbers of pollen tubes reaching the ovary. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Actin genes and their expression in pacific white shrimp, Litopenaeus vannamei.

PubMed

Zhang, Xiaoxi; Zhang, Xiaojun; Yuan, Jianbo; Du, Jiangli; Li, Fuhua; Xiang, Jianhai

2018-04-01

Actin is a multi-functional gene family that can be divided into muscle-type actins and non-muscle-type actins. In this study, 37 unigenes encoding actins were identified from RNA-Seq data of Pacific white shrimp, Litopenaeus vannamei. According to phylogenetic analysis, four and three cDNAs belong to cytoplasmic- and heart-type actins and were named LvActinCT and LvActinHT, respectively. 10 cDNAs belong to the slow-type skeletal muscle actins, and 18 belong to the fast-type skeletal muscle actins; they were designated LvActinSSK and LvActinFSK, respectively. Some muscle actin genes formed gene clusters in the genome. Multiple alternative transcription starts sites (ATSSs) were found for LvActinCT1. Based on the early developmental expression profile, almost all LvActins were highly expressed between the early limb bud and post-larval stages. Using LvActinSSK5 as probes, slow-type muscle was localized in pleopod muscle and superficial ventral muscle. We also found three actin genes that were down-regulated in the hemocytes of white spot syndrome virus (WSSV)- and Vibrio parahaemolyticus-infected L. vannamei. This study provides valuable information on the actin gene structure of shrimp, furthers our understanding of the shrimp muscle system and helps us develop strategies for disease control and sustainable shrimp farming.

Shared Enhancer Activity in the Limbs and Phallus and Functional Divergence of a Limb-Genital cis-Regulatory Element in Snakes.

PubMed

Infante, Carlos R; Mihala, Alexandra G; Park, Sungdae; Wang, Jialiang S; Johnson, Kenji K; Lauderdale, James D; Menke, Douglas B

2015-10-12

The amniote phallus and limbs differ dramatically in their morphologies but share patterns of signaling and gene expression in early development. Thus far, the extent to which genital and limb transcriptional networks also share cis-regulatory elements has remained unexplored. We show that many limb enhancers are retained in snake genomes, suggesting that these elements may function in non-limb tissues. Consistent with this, our analysis of cis-regulatory activity in mice and Anolis lizards reveals that patterns of enhancer activity in embryonic limbs and genitalia overlap heavily. In mice, deletion of HLEB, an enhancer of Tbx4, produces defects in hindlimbs and genitalia, establishing the importance of this limb-genital enhancer for development of these different appendages. Further analyses demonstrate that the HLEB of snakes has lost hindlimb enhancer function while retaining genital activity. Our findings identify roles for Tbx4 in genital development and highlight deep similarities in cis-regulatory activity between limbs and genitalia. Copyright © 2015 Elsevier Inc. All rights reserved.

Development of supercritical CO2 extraction of bioactive phytochemicals from black poplar (Populus nigra L.) buds followed by GC-MS and UHPLC-DAD-QqTOF-MS.

PubMed

Kuś, Piotr M; Okińczyc, Piotr; Jakovljević, Martina; Jokić, Stela; Jerković, Igor

2018-05-25

The supercritical CO 2 (SC-CO 2 ) extraction process of black poplar (Populus nigra L.) buds was optimized (pressure, temperature) based on the yields of major phytochemicals (volatiles and non-volatiles). The optimal settings were 30 MPa/60 °C. Major volatiles determined by GC-MS in the optimized SC-CO 2 extract (mg of benzyl salicylate equivalent (BSE) per 100 g of buds) were: pinostrobin chalcone (1574.2), β-eudesmol (640.8), α-eudesmol (581.9), 2-methyl-2-butenyl-p-coumarate (289.9), pentyl-p-coumarate (457.0), γ-eudesmol (294.4), and benzyl salicylate (289.2). Partial qualitative similarity was observed between SC-CO 2 extracts and corresponding hydrodistilled essential oil dominated by sesquiterpenes, but with lower yields. Major compounds (mg per 100 g of buds) identified by UHPLC-DAD-QqTOF-MS in the optimized SC-CO 2 extract were: pinostrobin (751.7), pinocembrin (485.6), 3-O-pinobanksin acetate and methyl-butenyl-p-coumarate (290.2; 144.9 of pinobanksin and p-coumaric acid equivalents, respectively). SC-CO 2 extraction was found useful for green, efficient and simultaneous extraction of both volatile/non-volatile, bioactive phytochemicals of poplar buds - precursors of poplar-type propolis. Copyright © 2018 Elsevier B.V. All rights reserved.

PpHB22, a member of HD-Zip proteins, activates PpDAM1 to regulate bud dormancy transition in 'Suli' pear (Pyrus pyrifolia White Pear Group).

PubMed

Yang, Qinsong; Niu, Qingfeng; Li, Jianzhao; Zheng, Xiaoyan; Ma, Yunjing; Bai, Songling; Teng, Yuanwen

2018-06-01

Homeodomain-leucine zipper (HD-Zip) proteins, which form one of the largest and most diverse families, regulate many biological processes in plants, including differentiation, flowering, vascular development, and stress signaling. Abscisic acid (ABA) has been proved to be one of the key regulators of bud dormancy and to influence several HD-Zip genes expression. However, the role of HD-Zip genes in regulating bud dormancy remains unclear. We identified 47 pear (P. pyrifolia White Pear Group) HD-Zip genes, which were classified into four subfamilies (HD-Zip I-IV). We further revealed that gene expression levels of some HD-Zip members were closely related to ABA concentrations in flower buds during dormancy transition. Exogenous ABA treatment confirmed that PpHB22 and several other HD-Zip genes responded to ABA. Yeast one-hybrid and dual luciferase assay results combining subcellular localization showed that PpHB22 was present in nucleus and directly induced PpDAM1 (dormancy associated MADS-box 1) expression. Thus, PpHB22 is a negative regulator of plant growth associated with the ABA response pathway and functions upstream of PpDAM1. These findings enrich our understanding of the function of HD-Zip genes related to the bud dormancy transition. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Processing umami and other tastes in mammalian taste buds.

PubMed

Roper, Stephen D; Chaudhari, Nirupa

2009-07-01

Neuroscientists are now coming to appreciate that a significant degree of information processing occurs in the peripheral sensory organs of taste prior to signals propagating to the brain. Gustatory stimulation causes taste bud cells to secrete neurotransmitters that act on adjacent taste bud cells (paracrine transmitters) as well as on primary sensory afferent fibers (neurocrine transmitters). Paracrine transmission, representing cell-cell communication within the taste bud, has the potential to shape the final signal output that taste buds transmit to the brain. The following paragraphs summarize current thinking about how taste signals generally, and umami taste in particular, are processed in taste buds.

Chemical Fate of a Metamorphic Inducer in Larvae-like Buds of the Cnidarian Cassiopea andromeda.

PubMed

Fleck, J

1998-02-01

Larvae-like vegetative buds of the scyphozoan Cassiopea andromeda metamorphose into polyps in the presence of oligopeptides that have a well-defined primary structure. Buds were incubated with the hexapeptide 14C-dansyl-GPGGPA, a representative inducer. Autoradiography of longitudinal sections of these buds revealed rapid internalization of peptide by the buds. Silver grain density was highest in the pre-pedal disc region (or aboral knob) of metamorphosing buds. Larvae and buds sporadically explore their habitat with this aboral knob, searching for a suitable solid substrate to which irreversible attachment will be made. Buds were incubated for 3, 8, or 16 h with 14C-dansyl-GPGGPA, then homogenized and the supernatants analyzed to determine the chemical fate of the inducer. The signal molecule was shown to be partly degraded to 14C-dansyl-GP, partly to 14C-dansyl-G, and in part still present in its original structure. These cleavage products were also found in the surrounding medium after an incubation time of 8 h with 14C-dansyl-GPGGPA, but did not induce metamorphosis. This study suggests that exposure of metamorphosis-inducing peptides to buds of Cassiopea andromeda results in signal termination.

Kinetics of human immunodeficiency virus budding and assembly

NASA Astrophysics Data System (ADS)

Zhang, Rui; Nguyen, Toan

2009-03-01

Human immunodeficiency virus (HIV) belongs to a large family of RNA viruses, retroviruses. Unlike budding of regular enveloped viruses, retroviruses bud concurrently with the assembly of retroviral capsids on the cell membrane. The kinetics of HIV (and other retroviruses) budding and assembly is therefore strongly affected by the elastic energy of the membrane and fundamentally different from regular viruses. The main result of this work shows that the kinetics is tunable from a fast budding process to a slow and effectively trapped partial budding process, by varying the attractive energy of retroviral proteins (call Gags), relative to the membrane elastic energy. When the Gag-Gag attraction is relatively high, the membrane elastic energy provides a kinetic barrier for the two pieces of the partial capsids to merge. This energy barrier determines the slowest step in the kinetics and the budding time. In the opposite limit, the membrane elastic energy provides not only a kinetic energy barrier, but a free energy barrier. The budding and assembly is effectively trapped at local free energy minimum, corresponding to a partially budded state. The time scale to escape from this metastable state is exponentially large. In both cases, our result fit with experimental measurements pretty well.

Construction of a pathological risk model of occult lymph node metastases for prognostication by semi-automated image analysis of tumor budding in early-stage oral squamous cell carcinoma

PubMed Central

Pedersen, Nicklas Juel; Jensen, David Hebbelstrup; Lelkaitis, Giedrius; Kiss, Katalin; Charabi, Birgitte; Specht, Lena; von Buchwald, Christian

2017-01-01

It is challenging to identify at diagnosis those patients with early oral squamous cell carcinoma (OSCC), who have a poor prognosis and those that have a high risk of harboring occult lymph node metastases. The aim of this study was to develop a standardized and objective digital scoring method to evaluate the predictive value of tumor budding. We developed a semi-automated image-analysis algorithm, Digital Tumor Bud Count (DTBC), to evaluate tumor budding. The algorithm was tested in 222 consecutive patients with early-stage OSCC and major endpoints were overall (OS) and progression free survival (PFS). We subsequently constructed and cross-validated a binary logistic regression model and evaluated its clinical utility by decision curve analysis. A high DTBC was an independent predictor of both poor OS and PFS in a multivariate Cox regression model. The logistic regression model was able to identify patients with occult lymph node metastases with an area under the curve (AUC) of 0.83 (95% CI: 0.78–0.89, P <0.001) and a 10-fold cross-validated AUC of 0.79. Compared to other known histopathological risk factors, the DTBC had a higher diagnostic accuracy. The proposed, novel risk model could be used as a guide to identify patients who would benefit from an up-front neck dissection. PMID:28212555

Complementary transcriptome and proteome profiling in cabbage buds of a recessive male sterile mutant provides new insights into male reproductive development.

PubMed

Ji, Jialei; Yang, Limei; Fang, Zhiyuan; Zhuang, Mu; Zhang, Yangyong; Lv, Honghao; Liu, Yumei; Li, Zhansheng

2018-05-15

Plant male reproductive development is a very complex biological process that involves multiple metabolic pathways. To reveal novel insights into male reproductive development, we conducted an integrated profiling of gene activity in the developing buds of a cabbage recessive genetic male sterile mutant. Using RNA-Seq and label-free quantitative proteomics, 2881 transcripts and 1245 protein species were identified with significant differential abundance between the male sterile line 83121A and its isogenic maintainer line 83121B. Analyses of function annotations and correlations between transcriptome and proteome and protein interaction networks were also conducted, which suggested that the male sterility involves a complex regulatory pattern. Moreover, several key biological processes, such as fatty acid metabolism, tapetosome biosynthesis, amino acid metabolism and protein synthesis and degradation were identified as being of relevance to male reproductive development. A large number of protein species involved in sporopollenin synthesis, amino acid synthesis, ribosome assembly, protein processing in endoplasmic reticulum and lipid transfer were observed to be significantly down-accumulated in 83121A buds, indicating their potential roles in the regulation of cabbage microspore abortion. In summary, the conjoint analysis of the transcriptome and proteome provided a global picture regarding the molecular dynamics in male sterile buds of 83121A. Male sterile mutants are excellent materials for the study of plant male reproductive development. This study revealed the molecular dynamics of recessive male sterility in cabbage at the transcriptome and proteome levels, which deepens our understanding of the metabolic pathways involved in male development. Moreover, the male sterility-related genes identified in this study could provide a reference for the artificial regulation of cabbage fertility by using genetic engineering technology, which may result in potential applications in agriculture such as production of hybrid seeds using male sterility. Copyright © 2018 Elsevier B.V. All rights reserved.

BDNF is required for taste axon regeneration following unilateral chorda tympani nerve section.

PubMed

Meng, Lingbin; Huang, Tao; Sun, Chengsan; Hill, David L; Krimm, Robin

2017-07-01

Taste nerves readily regenerate to reinnervate denervated taste buds; however, factors required for regeneration have not yet been identified. When the chorda tympani nerve is sectioned, expression of brain-derived neurotrophic factor (BDNF) remains high in the geniculate ganglion and lingual epithelium, despite the loss of taste buds. These observations suggest that BDNF is present in the taste system after nerve section and may support taste nerve regeneration. To test this hypothesis, we inducibly deleted Bdnf during adulthood in mice. Shortly after Bdnf gene recombination, the chorda tympani nerve was unilaterally sectioned causing a loss of both taste buds and neurons, irrespective of BDNF levels. Eight weeks after nerve section, however, regeneration was differentially affected by Bdnf deletion. In control mice, there was regeneration of the chorda tympani nerve and taste buds reappeared with innervation. In contrast, few taste buds were reinnervated in mice lacking normal Bdnf expression such that taste bud number remained low. In all genotypes, taste buds that were reinnervated were normal-sized, but non-innervated taste buds remained small and atrophic. On the side of the tongue contralateral to the nerve section, taste buds for some genotypes became larger and all taste buds remained innervated. Our findings suggest that BDNF is required for nerve regeneration following gustatory nerve section. Copyright © 2017 Elsevier Inc. All rights reserved.

Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection.

PubMed

Li, Yi-Ke; Yang, Juan-Mei; Huang, Yi-Bo; Ren, Dong-Dong; Chi, Fang-Lu

2015-06-01

The morphological changes that occur in the taste buds after denervation are not well understood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups: control, unilateral chorda tympani nerve transection and unilateral chorda tympani nerve transection + lingual nerve transection. Rats were allowed up to 42 days of recovery before being euthanized. The taste buds were visualized using a cytokeratin 8 antibody. Taste bud counts, volumes and taste receptor cell numbers were quantified and compared among groups. No significant difference was detected between the chorda tympani nerve transection and chorda tympani nerve transection + lingual nerve transection groups. Taste bud counts, volumes and taste receptor cell numbers on the ipsilateral side all decreased significantly compared with control. On the contralateral side, the number of taste buds remained unchanged over time, but they were larger, and taste receptor cells were more numerous postoperatively. There was no evidence for a role of the trigeminal branch of the lingual nerve in maintaining the structural integrity of the anterior taste buds.

Comparative ultrastructure of vallate, foliate and fungiform taste buds of golden Syrian hamster.

PubMed

Miller, R L; Chaudhry, A P

1976-01-01

A fine-structure study of the hamster fungiform, foliate and vallate taste buds was undertaken for comparative purposes. All three taste bud types shared in common composition of the dark cells, light cells, basal cells, nerve fibers and nerve endings and undifferentiated peripheral cells, but morphological difference existed among them. The foliate and vallate taste buds were quite similar in their ultrastructural morphology. Their dark cells displayed long apical necks, long apical microvilli, apical osmiophilic secretory granules and an abundant rough endoplasmic reticulum. The dark cells of the fungiform taste buds, however, showed no neck formation and lacked apical osmiophilic granules. They had short apical microvilli and relatively scant rough endoplasmic reticulum. There was no difference in the fine structure features of the light cells, basal cells and neural elements of different types of taste buds. Both light and dark cells were much more readily distinguishable in foliate and vallate buds than in fungiform buds at both light-and electron-microscopic levels. Foliate and vallate buds demonstrated homogeneous dense substance within the taste pores while fungiform pores were frequently empty. It is speculated that the differences in taste bud morphology may be due to their different lingual locations and/or may be a reflection of the differences in the inductive influences from different nerves. Furthermore, structural differences may be responsible for varying thresholds to different taste modalities.

Role for cER and Mmr1p in anchorage of mitochondria at sites of polarized surface growth in budding yeast.

PubMed

Swayne, Theresa C; Zhou, Chun; Boldogh, Istvan R; Charalel, Joseph K; McFaline-Figueroa, José Ricardo; Thoms, Sven; Yang, Christine; Leung, Galen; McInnes, Joseph; Erdmann, Ralf; Pon, Liza A

2011-12-06

Mitochondria accumulate at neuronal and immunological synapses and yeast bud tips and associate with the ER during phospholipid biosynthesis, calcium homeostasis, and mitochondrial fission. Here we show that mitochondria are associated with cortical ER (cER) sheets underlying the plasma membrane in the bud tip and confirm that a deletion in YPT11, which inhibits cER accumulation in the bud tip, also inhibits bud tip anchorage of mitochondria. Time-lapse imaging reveals that mitochondria are anchored at specific sites in the bud tip. Mmr1p, a member of the DSL1 family of tethering proteins, localizes to punctate structures on opposing surfaces of mitochondria and cER sheets underlying the bud tip and is recovered with isolated mitochondria and ER. Deletion of MMR1 impairs bud tip anchorage of mitochondria without affecting mitochondrial velocity or cER distribution. Deletion of the phosphatase PTC1 results in increased Mmr1p phosphorylation, mislocalization of Mmr1p, defects in association of Mmr1p with mitochondria and ER, and defects in bud tip anchorage of mitochondria. These findings indicate that Mmr1p contributes to mitochondrial inheritance as a mediator of anchorage of mitochondria to cER sheets in the yeast bud tip and that Ptc1p regulates Mmr1p phosphorylation, localization, and function. Copyright © 2011 Elsevier Ltd. All rights reserved.

Inhibition of Wnt signaling by Wise (Sostdc1) and negative feedback from Shh controls tooth number and patterning.

PubMed

Ahn, Youngwook; Sanderson, Brian W; Klein, Ophir D; Krumlauf, Robb

2010-10-01

Mice carrying mutations in Wise (Sostdc1) display defects in many aspects of tooth development, including tooth number, size and cusp pattern. To understand the basis of these defects, we have investigated the pathways modulated by Wise in tooth development. We present evidence that, in tooth development, Wise suppresses survival of the diastema or incisor vestigial buds by serving as an inhibitor of Lrp5- and Lrp6-dependent Wnt signaling. Reducing the dosage of the Wnt co-receptor genes Lrp5 and Lrp6 rescues the Wise-null tooth phenotypes. Inactivation of Wise leads to elevated Wnt signaling and, as a consequence, vestigial tooth buds in the normally toothless diastema region display increased proliferation and continuous development to form supernumerary teeth. Conversely, gain-of-function studies show that ectopic Wise reduces Wnt signaling and tooth number. Our analyses demonstrate that the Fgf and Shh pathways are major downstream targets of Wise-regulated Wnt signaling. Furthermore, our experiments revealed that Shh acts as a negative-feedback regulator of Wnt signaling and thus determines the fate of the vestigial buds and later tooth patterning. These data provide insight into the mechanisms that control Wnt signaling in tooth development and into how crosstalk among signaling pathways controls tooth number and morphogenesis.

Proximal—distal pattern formation in Drosophila: cell autonomous requirement for Distal-less gene activity in limb development

PubMed Central

Cohen, Stephen M.; Jürgens, Gerd

1989-01-01

Limb development in the Drosophila embryo requires a pattern-forming system to organize positional information along the proximal–distal axis of the limb. This system must function in the context of the well characterized anterior–posterior and dorsal–ventral pattern-forming systems that are required to organize the body plan of the embryo. By genetic criteria the Distal-less gene appears to play a central role in limb development. Lack-of-function Distal-less mutations cause the deletion of a specific subset of embryonic peripheral sense organs that represent the evolutionary remnants of larval limbs. Distal-less activity is also required in the imaginal discs for the development of adult limbs. This requirement is cell autonomous and region specific within the developing limb primordium. Production of genetically mosaic imaginal discs, in which clones of cells lack Distal-less activity, indicates the existence of an organized proximal–distal positional information in very young imaginal disc primordia. We suggest that this graded positional information may depend on the activity of the Distal-less gene. Images PMID:16453891

Generation of chondrocytes from embryonic stem cells.

PubMed

Khillan, Jaspal Singh

2006-01-01

Pluripotent embryonic stem (ES) cells have complete potential for all the primary germ layers, such as ectoderm, mesoderm, and endoderm. However, the cellular and molecular mechanisms that control their lineage-restricted differentiation are not understood. Although embryoid bodies, which are formed because of the spontaneous differentiation of ES cells, have been used to study the differentiation into different cell types, including neurons, chondrocytes, insulin-producing cells, bone-forming cells, hematopoietic cells, and so on, this system has limitations for investigating the upstream events that lead to commitment of cells that occur during the inaccessible period of development. Recent developments in human ES cells have offered a challenge to develop strategies for understanding the basic mechanisms that play a key role in differentiation of stem cell into specific cell types for their applications in regenerative medicine and cell-based therapies. A micromass culture system was developed to induce the differentiation of ES cells into chondrocytes, the cartilage-producing cells, as a model to investigate the upstream events of stem cell differentiation. ES cells were co-cultured with limb bud progenitor cells. A high percentage of differentiated cells exhibit typical morphological characteristics of chondrocytes and express cartilage matrix genes such as collagen type II and proteoglycans, suggesting that signals from the progenitor cells are sufficient to induce ES cells into the chondrogenic lineage. Degeneration of cartilage in the joints is associated with osteoarthritis, which affects the quality of life of human patients. Therefore, the quantitative production of chondrocytes can be a powerful resource to alleviate the suffering of those patients.

The Veiled Chameleon (Chamaeleo calyptratus Duméril and Duméril 1851): A Model for Studying Reptile Body Plan Development and Evolution.

PubMed

Diaz, Raul E; Anderson, Christopher V; Baumann, Diana P; Kupronis, Richard; Jewell, David; Piraquive, Christina; Kupronis, Jill; Winter, Kristy; Bertocchini, Federica; Trainor, Paul A

2015-08-26

Vertebrate model organisms have facilitated the discovery and exploration of morphogenetic events and developmental pathways that underpin normal and pathological embryological events. In contrast to amniotes such as Mus musculus (Mammalia) and Gallus gallus (Aves), our understanding of early patterning and developmental events in reptiles (particularly nonavians) remains weak. Squamate reptiles (lizards, snakes, and amphisbaenians) comprise approximately one-third of all living amniotes. But studies of early squamate development have been limited because, in most members of this lineage, embryo development at the time of oviposition is very advanced (limb bud stages and older). In many cases, squamates give birth to fully developed offspring. However, in the veiled chameleon (Chamaeleo calyptratus), embryos have progressed only to a primitive pregastrula stage at the time of oviposition. Furthermore, the body plan of the veiled chameleon is highly specialized for climbing in an arboreal environment. It possesses an entire suite of skeletal and soft anatomical modifications, including cranioskeletal ornamentation, lingual anatomy and biomechanics for projection, autopodial clefting for grasping, adaptations for rapid integumental color changes, a prehensile tail with a lack of caudal autotomy, the loss of the tympanum in the middle ear, and the acquisition of turreted eyes. Thus, C. calyptratus is an important model organism for studying the role of ecological niche specialization, as well as genetic and morphological evolution within an adaptive framework. More importantly, this species is easily bred in captivity, with only a small colony (<10 individuals) needed to obtain hundreds of embryos every year. © 2015 Cold Spring Harbor Laboratory Press.

Trehalose 6-phosphate is involved in triggering axillary bud outgrowth in garden pea (Pisum sativum L.).

PubMed

Fichtner, Franziska; Barbier, Francois F; Feil, Regina; Watanabe, Mutsumi; Annunziata, Maria Grazia; Chabikwa, Tinashe G; Höfgen, Rainer; Stitt, Mark; Beveridge, Christine A; Lunn, John E

2017-11-01

Trehalose 6-phosphate (Tre6P) is a signal of sucrose availability in plants, and has been implicated in the regulation of shoot branching by the abnormal branching phenotypes of Arabidopsis (Arabidopsis thaliana) and maize (Zea mays) mutants with altered Tre6P metabolism. Decapitation of garden pea (Pisum sativum) plants has been proposed to release the dormancy of axillary buds lower down the stem due to changes in sucrose supply, and we hypothesized that this response is mediated by Tre6P. Decapitation led to a rapid and sustained rise in Tre6P levels in axillary buds, coinciding with the onset of bud outgrowth. This response was suppressed by simultaneous defoliation that restricts the supply of sucrose to axillary buds in decapitated plants. Decapitation also led to a rise in amino acid levels in buds, but a fall in phosphoenolpyruvate and 2-oxoglutarate. Supplying sucrose to stem node explants in vitro triggered a concentration-dependent increase in the Tre6P content of the buds that was highly correlated with their rate of outgrowth. These data show that changes in bud Tre6P levels are correlated with initiation of bud outgrowth following decapitation, suggesting that Tre6P is involved in the release of bud dormancy by sucrose. Tre6P might also be linked to a reconfiguration of carbon and nitrogen metabolism to support the subsequent growth of the bud into a new shoot. © 2017 The Authors The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.

A New Animal Model for Developing a Somatosensory Neural Interface for Prosthetic Limbs

DTIC Science & Technology

2008-02-12

interface for neuroprosthetic limbs . PI: Douglas J. Weber, Ph.D. University of Pittsburgh 1 10/15/2007 Scientific progress and accomplishments. We...information to the brain. A new animal model for developing a somatosensory neural interface for neuroprosthetic limbs . PI: Douglas J. Weber, Ph.D...A new animal model for developing a somatosensory neural interface for neuroprosthetic limbs . PI: Douglas J. Weber, Ph.D. University of Pittsburgh

Evaluation of twig pre-harvest temperature for effective cryopreservation of Vaccinium dormant buds

USDA-ARS?s Scientific Manuscript database

Cryopreservation of plant material by dormant buds is less expensive than using shoot tips; however currently, dormant buds are used only for preservation of selected temperate tree and shrub species. Using dormant buds could be an efficient strategy for long-term preservation of blueberry (Vacciniu...

Transcription profiling of the chilling requirement for bud break in apples: a putative role for FLC-like genes.

PubMed

Porto, Diogo Denardi; Bruneau, Maryline; Perini, Pâmela; Anzanello, Rafael; Renou, Jean-Pierre; dos Santos, Henrique Pessoa; Fialho, Flávio Bello; Revers, Luís Fernando

2015-05-01

Apple production depends on the fulfilment of a chilling requirement for bud dormancy release. Insufficient winter chilling results in irregular and suboptimal bud break in the spring, with negative impacts on apple yield. Trees from apple cultivars with contrasting chilling requirements for bud break were used to investigate the expression of the entire set of apple genes in response to chilling accumulation in the field and controlled conditions. Total RNA was analysed on the AryANE v.1.0 oligonucleotide microarray chip representing 57,000 apple genes. The data were tested for functional enrichment, and differential expression was confirmed by real-time PCR. The largest number of differentially expressed genes was found in samples treated with cold temperatures. Cold exposure mostly repressed expression of transcripts related to photosynthesis, and long-term cold exposure repressed flavonoid biosynthesis genes. Among the differentially expressed selected candidates, we identified genes whose annotations were related to the circadian clock, hormonal signalling, regulation of growth, and flower development. Two genes, annotated as FLOWERING LOCUS C-like and MADS AFFECTING FLOWERING, showed strong differential expression in several comparisons. One of these two genes was upregulated in most comparisons involving dormancy release, and this gene's chromosomal position co-localized with the confidence interval of a major quantitative trait locus for the timing of bud break. These results indicate that photosynthesis and auxin transport are major regulatory nodes of apple dormancy and unveil strong candidates for the control of bud dormancy. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Expression of the voltage-gated potassium channel KCNQ1 in mammalian taste bud cells and the effect of its null-mutation on taste preferences.

PubMed

Wang, Hong; Iguchi, Naoko; Rong, Qi; Zhou, Minliang; Ogunkorode, Martina; Inoue, Masashi; Pribitkin, Edmund A; Bachmanov, Alexander A; Margolskee, Robert F; Pfeifer, Karl; Huang, Liquan

2009-01-20

Vertebrate taste buds undergo continual cell turnover. To understand how the gustatory progenitor cells in the stratified lingual epithelium migrate and differentiate into different types of mature taste cells, we sought to identify genes that were selectively expressed in taste cells at different maturation stages. Here we report the expression of the voltage-gated potassium channel KCNQ1 in mammalian taste buds of mouse, rat, and human. Immunohistochemistry and nuclear staining showed that nearly all rodent and human taste cells express this channel. Double immunostaining with antibodies against type II and III taste cell markers validated the presence of KCNQ1 in these two types of cells. Co-localization studies with cytokeratin 14 indicated that KCNQ1 is also expressed in type IV basal precursor cells. Null mutation of the kcnq1 gene in mouse, however, did not alter the gross structure of taste buds or the expression of taste signaling molecules. Behavioral assays showed that the mutant mice display reduced preference to some umami substances, but not to any other taste compounds tested. Gustatory nerve recordings, however, were unable to detect any significant change in the integrated nerve responses of the mutant mice to umami stimuli. These results suggest that although it is expressed in nearly all taste bud cells, the function of KCNQ1 is not required for gross taste bud development or peripheral taste transduction pathways, and the reduced preference of kcnq1-null mice in the behavioral assays may be attributable to the deficiency in the central nervous system or other organs.

Targeted taste cell-specific overexpression of brain-derived neurotrophic factor in adult taste buds elevates phosphorylated TrkB protein levels in taste cells, increases taste bud size, and promotes gustatory innervation.

PubMed

Nosrat, Irina V; Margolskee, Robert F; Nosrat, Christopher A

2012-05-11

Brain-derived neurotrophic factor (BDNF) is the most potent neurotrophic factor in the peripheral taste system during embryonic development. It is also expressed in adult taste buds. There is a lack of understanding of the role of BDNF in the adult taste system. To address this, we generated novel transgenic mice in which transgene expression was driven by an α-gustducin promoter coupling BDNF expression to the postnatal expression of gustducin in taste cells. Immunohistochemistry revealed significantly stronger BDNF labeling in taste cells of high BDNF-expressing mouse lines compared with controls. We show that taste buds in these mice are significantly larger and have a larger number of taste cells compared with controls. To examine whether innervation was affected in Gust-BDNF mice, we used antibodies to neural cell adhesion molecule (NCAM) and ATP receptor P2X3. The total density of general innervation and specifically the gustatory innervation was markedly increased in high BDNF-expressing mice compared with controls. TrkB and NCAM gene expression in laser capture microdissected taste epithelia were significantly up-regulated in these mice. Up-regulation of TrkB transcripts in taste buds and elevated taste cell-specific TrkB phosphorylation in response to increased BDNF levels indicate that BDNF controls the expression and activation of its high affinity receptor in taste cells. This demonstrates a direct taste cell function for BDNF. BDNF also orchestrates and maintains taste bud innervation. We propose that the Gust-BDNF transgenic mouse models can be employed to further dissect the specific roles of BDNF in the adult taste system.

Targeted Taste Cell-specific Overexpression of Brain-derived Neurotrophic Factor in Adult Taste Buds Elevates Phosphorylated TrkB Protein Levels in Taste Cells, Increases Taste Bud Size, and Promotes Gustatory Innervation*

PubMed Central

Nosrat, Irina V.; Margolskee, Robert F.; Nosrat, Christopher A.

2012-01-01

Brain-derived neurotrophic factor (BDNF) is the most potent neurotrophic factor in the peripheral taste system during embryonic development. It is also expressed in adult taste buds. There is a lack of understanding of the role of BDNF in the adult taste system. To address this, we generated novel transgenic mice in which transgene expression was driven by an α-gustducin promoter coupling BDNF expression to the postnatal expression of gustducin in taste cells. Immunohistochemistry revealed significantly stronger BDNF labeling in taste cells of high BDNF-expressing mouse lines compared with controls. We show that taste buds in these mice are significantly larger and have a larger number of taste cells compared with controls. To examine whether innervation was affected in Gust-BDNF mice, we used antibodies to neural cell adhesion molecule (NCAM) and ATP receptor P2X3. The total density of general innervation and specifically the gustatory innervation was markedly increased in high BDNF-expressing mice compared with controls. TrkB and NCAM gene expression in laser capture microdissected taste epithelia were significantly up-regulated in these mice. Up-regulation of TrkB transcripts in taste buds and elevated taste cell-specific TrkB phosphorylation in response to increased BDNF levels indicate that BDNF controls the expression and activation of its high affinity receptor in taste cells. This demonstrates a direct taste cell function for BDNF. BDNF also orchestrates and maintains taste bud innervation. We propose that the Gust-BDNF transgenic mouse models can be employed to further dissect the specific roles of BDNF in the adult taste system. PMID:22442142

Genetic Interactions Between Shox2 and Hox Genes During the Regional Growth and Development of the Mouse Limb

PubMed Central

Neufeld, Stanley J.; Wang, Fan; Cobb, John

2014-01-01

The growth and development of the vertebrate limb relies on homeobox genes of the Hox and Shox families, with their independent mutation often giving dose-dependent effects. Here we investigate whether Shox2 and Hox genes function together during mouse limb development by modulating their relative dosage and examining the limb for nonadditive effects on growth. Using double mRNA fluorescence in situ hybridization (FISH) in single embryos, we first show that Shox2 and Hox genes have associated spatial expression dynamics, with Shox2 expression restricted to the proximal limb along with Hoxd9 and Hoxa11 expression, juxtaposing the distal expression of Hoxa13 and Hoxd13. By generating mice with all possible dosage combinations of mutant Shox2 alleles and HoxA/D cluster deletions, we then show that their coordinated proximal limb expression is critical to generate normally proportioned limb segments. These epistatic interactions tune limb length, where Shox2 underexpression enhances, and Shox2 overexpression suppresses, Hox-mutant phenotypes. Disruption of either Shox2 or Hox genes leads to a similar reduction in Runx2 expression in the developing humerus, suggesting their concerted action drives cartilage maturation during normal development. While we furthermore provide evidence that Hox gene function influences Shox2 expression, this regulation is limited in extent and is unlikely on its own to be a major explanation for their genetic interaction. Given the similar effect of human SHOX mutations on regional limb growth, Shox and Hox genes may generally function as genetic interaction partners during the growth and development of the proximal vertebrate limb. PMID:25217052

Genetic interactions between Shox2 and Hox genes during the regional growth and development of the mouse limb.

PubMed

Neufeld, Stanley J; Wang, Fan; Cobb, John

2014-11-01

The growth and development of the vertebrate limb relies on homeobox genes of the Hox and Shox families, with their independent mutation often giving dose-dependent effects. Here we investigate whether Shox2 and Hox genes function together during mouse limb development by modulating their relative dosage and examining the limb for nonadditive effects on growth. Using double mRNA fluorescence in situ hybridization (FISH) in single embryos, we first show that Shox2 and Hox genes have associated spatial expression dynamics, with Shox2 expression restricted to the proximal limb along with Hoxd9 and Hoxa11 expression, juxtaposing the distal expression of Hoxa13 and Hoxd13. By generating mice with all possible dosage combinations of mutant Shox2 alleles and HoxA/D cluster deletions, we then show that their coordinated proximal limb expression is critical to generate normally proportioned limb segments. These epistatic interactions tune limb length, where Shox2 underexpression enhances, and Shox2 overexpression suppresses, Hox-mutant phenotypes. Disruption of either Shox2 or Hox genes leads to a similar reduction in Runx2 expression in the developing humerus, suggesting their concerted action drives cartilage maturation during normal development. While we furthermore provide evidence that Hox gene function influences Shox2 expression, this regulation is limited in extent and is unlikely on its own to be a major explanation for their genetic interaction. Given the similar effect of human SHOX mutations on regional limb growth, Shox and Hox genes may generally function as genetic interaction partners during the growth and development of the proximal vertebrate limb. Copyright © 2014 by the Genetics Society of America.

Embryonic Wnt gene expression in the nitrofen-induced hypoplastic lung using 3-dimensional imaging.

PubMed

Takayasu, Hajime; Murphy, Paula; Sato, Hideaki; Doi, Takashi; Puri, Prem

2010-11-01

Wnts have been reported to play a key role in the lung morphogenesis. We have previously reported that pulmonary gene expression of Wnt2 and Wnt7b is downregulated on day 15 of gestation in the nitrofen-induced congenital diaphragmatic hernia (CDH) model. However, the distribution pattern of gene expression of Wnts in the very early lung development remains unclear. Optical projection tomography (OPT) is a new technique for 3-dimensional imaging of small developing organs and gene distribution combined with whole-mount in situ hybridization. We designed this study to investigate the distribution pattern of Wnts gene expression in lung buds of nitrofen-induced CDH model using OPT. Embryos from normal and nitrofen-treated dams were harvested on embryonic day 10 (E10), and divided into controls and nitrofen group, respectively. Whole-mount in situ hybridization to detect transcripts of Wnt2 and Wnt7b was performed, analyzed, and reconstructed using OPT. The expression of Wnt2 transcripts was detected in the lung bud mesenchyme and markedly diminished in nitrofen group compared to controls, whereas Wnt7b transcripts were expressed in the mesoderm of bronchi and the lung bud with no detectable difference between 2 groups. We provide evidence for the first time that Wnt2 expression is downregulated at lung bud stage in the nitrofen model. Optical projection tomography is potentially a useful approach to visualize both gene expression and morphology during very early stages of lung development. Copyright © 2010 Elsevier Inc. All rights reserved.

Survival and development of Heliothis virescens (Lepidoptera: Noctuidae) larvae on isogenic tobacco lines with different levels of alkaloids.

PubMed

Jackson, D Michael; Johnson, A W; Stephenson, M G

2002-12-01

Levels of pyridine alkaloids were measured in 18 tobacco, Nicotiana tabacum L., entries from three parental isolines ('NC 95', 'SC 58', and 'Coker 139'), grown at Tifton, GA, Florence, SC, and Oxford, NC, in 1991. Levels of alkaloids in bud leaves (first fully unfolded leaf below the apical leaf bud) were negatively correlated to natural infestation ratings of tobacco budworm larvae, Heliothis virescens (F.), 7 wk after transplanting. For artificially infested bud leaves at Oxford, there was a significant negative correlation between levels of total alkaloids and larval weights after 1 wk of feeding. In 1992, four entries from the 'NC 95' isoline were grown at Oxford, and samples for alkaloid analyses were taken every 2 wk at several leaf positions on each plant. During weeks 4, 8, 12, and 16, second instar tobacco budworms were caged on individual, intact leaves inside perforated plastic bags in the field. The survival and development of tobacco budworm larvae after 1 wk were negatively correlated with levels of alkaloids at the various leaf positions. Larvae survived better and grew faster on the bud leaves of each entry where alkaloid levels were lower than they did on leaves further down the stalk where alkaloid levels were higher. More larvae survived on the lower leaves of the low alkaloid lines than on the lower leaves of the high alkaloid lines. Even moderate increases in pyridine alkaloids had negative effects on tobacco budworm survival and development. Nicotine constituted >97% of the pyridine alkaloids in the 'NC95' isoline each year.

Effects of light and growth regulators on adventitious bud formation in horseradish (Armoracia rusticana).

PubMed

Kamada, H; Tachikawa, Y; Saitou, T; Harada, H

1995-07-01

To clarify that the presence of Ri T-DNA genes are not prerequisite for the light-induced bud formation in horseradish (Armoracia rusticana) hairy roots, leaf and root segments of nontransformed horseradish plants were used as explants. Bud formation from nontransformed tissues was observed in hormone-free medium under 16 h daylight conditions, but not under continuous darkness. To investigate the effects of growth regulators on bud formation, leaf and root explants were treated with auxin (1-naphthaleneacetic acid; NAA) and / or cytokinin (6-benzyl-aminopurine; BA). The most effective treatment in the dark to stimulate bud formation was BA at 1 mg·1(-1). These results show that adventitious bud formation in horseradish can be induced by light and growth regulators, and especially cytokinin, may be involved in bud formation, irrespective of whether the tissues were transformed with Ri T-DNA.

Anthropometric correlations between parts of the upper and lower limb: models for personal identification in a Sudanese population.

PubMed

Ahmed, Altayeb Abdalla

2016-09-01

Identification of a deceased individual is an essential component of medicolegal practice. However, personal identification based on commingled limbs or parts of limbs, necessary in investigations of mass disasters or some crimes, is a difficult task. Limb measurements have been utilized in the development of biological parameters for personal identification, but the possibility to estimate the dimensions of parts of limbs other than hands and feet has not been assessed. The present study proposes an approach to estimate the dimensions of various parts of limbs based on other limb measurements. The study included 320 Sudanese adults, with equal representation of men and women. Nine limb dimensions were measured (five based on the upper limb, four based on the lower limb), and extensive statistical analysis of the distribution of values was performed. The results showed that all of the measured dimensions were sexually dimorphic and that there was a significant positive correlation between the dimensions of various parts of limbs. Regression models (direct and stepwise) were developed to estimate the dimensions of parts of limbs based on measurements pertaining to one or more other parts of limbs. The study revealed that the dimensions of parts of the upper and lower limb can be estimated from one another. These findings can be used in medicolegal practice and extended to constructive surgery, orthopedics, and prosthesis design for lost limbs.

Greater bud outgrowth of Bromus inermis than Pascopyrum smithii under multiple environmental conditions

Treesearch

Jacqueline P. Ott; Jack L. Butler; Yuping Rong; Lan. Xu

2017-01-01

Tiller recruitment of perennial grasses in mixed-grass prairie primarily occurs from belowground buds. Environmental conditions, such as temperature, soil moisture and grazing can affect bud outgrowth of both invasive and native perennial grasses. Differential bud outgrowth responses of native and invasive species to climate change and grazing could alter...

48 CFR 1419.202-70 - Acquisition screening and BUDS recommendations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BUDS recommendations. 1419.202-70 Section 1419.202-70 Federal Acquisition Regulations System DEPARTMENT... screening and BUDS recommendations. (a) For open market acquisitions estimated to exceed the SAT, the DI... document the rationale for not accepting a BUDS recommendation on DI Form 1886, under “Notes.” (See FAR 19...

Complex bud architecture and cell-specific chemical patterns enable supercooling of Picea abies bud primordial

USDA-ARS?s Scientific Manuscript database

Bud primordia of Picea abies, despite a frozen shoot, stay ice free down to -50 °C by a mechanism termed supercooling whose biophysical and biochemical requirements are poorly understood. Bud architecture was assessed by 3D-reconstruction, supercooling and freezing patterns by infrared video thermog...

β-catenin is required for taste bud cell renewal and behavioral taste perception in adult mice.

PubMed

Gaillard, Dany; Bowles, Spencer G; Salcedo, Ernesto; Xu, Mingang; Millar, Sarah E; Barlow, Linda A

2017-08-01

Taste stimuli are transduced by taste buds and transmitted to the brain via afferent gustatory fibers. Renewal of taste receptor cells from actively dividing progenitors is finely tuned to maintain taste sensitivity throughout life. We show that conditional β-catenin deletion in mouse taste progenitors leads to rapid depletion of progenitors and Shh+ precursors, which in turn causes taste bud loss, followed by loss of gustatory nerve fibers. In addition, our data suggest LEF1, TCF7 and Wnt3 are involved in a Wnt pathway regulatory feedback loop that controls taste cell renewal in the circumvallate papilla epithelium. Unexpectedly, taste bud decline is greater in the anterior tongue and palate than in the posterior tongue. Mutant mice with this regional pattern of taste bud loss were unable to discern sweet at any concentration, but could distinguish bitter stimuli, albeit with reduced sensitivity. Our findings are consistent with published reports wherein anterior taste buds have higher sweet sensitivity while posterior taste buds are better tuned to bitter, and suggest β-catenin plays a greater role in renewal of anterior versus posterior taste buds.

Sonic hedgehog from both nerves and epithelium is a key trophic factor for taste bud maintenance.

PubMed

Castillo-Azofeifa, David; Losacco, Justin T; Salcedo, Ernesto; Golden, Erin J; Finger, Thomas E; Barlow, Linda A

2017-09-01

The integrity of taste buds is intimately dependent on an intact gustatory innervation, yet the molecular nature of this dependency is unknown. Here, we show that differentiation of new taste bud cells, but not progenitor proliferation, is interrupted in mice treated with a hedgehog (Hh) pathway inhibitor (HPI), and that gustatory nerves are a source of sonic hedgehog (Shh) for taste bud renewal. Additionally, epithelial taste precursor cells express Shh transiently, and provide a local supply of Hh ligand that supports taste cell renewal. Taste buds are minimally affected when Shh is lost from either tissue source. However, when both the epithelial and neural supply of Shh are removed, taste buds largely disappear. We conclude Shh supplied by taste nerves and local taste epithelium act in concert to support continued taste bud differentiation. However, although neurally derived Shh is in part responsible for the dependence of taste cell renewal on gustatory innervation, neurotrophic support of taste buds likely involves a complex set of factors. © 2017. Published by The Company of Biologists Ltd.

Perichondrium phenotype and border function are regulated by Ext1 and heparan sulfate in developing long bones: a mechanism likely deranged in Hereditary Multiple Exostoses.

PubMed

Huegel, Julianne; Mundy, Christina; Sgariglia, Federica; Nygren, Patrik; Billings, Paul C; Yamaguchi, Yu; Koyama, Eiki; Pacifici, Maurizio

2013-05-01

During limb skeletogenesis the cartilaginous long bone anlagen and their growth plates become delimited by perichondrium with which they interact functionally. Yet, little is known about how, despite being so intimately associated with cartilage, perichondrium acquires and maintains its distinct phenotype and exerts its border function. Because perichondrium becomes deranged and interrupted by cartilaginous outgrowths in Hereditary Multiple Exostoses (HME), a pediatric disorder caused by EXT mutations and consequent heparan sulfate (HS) deficiency, we asked whether EXT genes and HS normally have roles in establishing its phenotype and function. Indeed, conditional Ext1 ablation in perichondrium and lateral chondrocytes flanking the epiphyseal region of mouse embryo long bone anlagen - a region encompassing the groove of Ranvier - caused ectopic cartilage formation. A similar response was observed when HS function was disrupted in long bone anlagen explants by genetic, pharmacological or enzymatic means, a response preceded by ectopic BMP signaling within perichondrium. These treatments also triggered excess chondrogenesis and cartilage nodule formation and overexpression of chondrogenic and matrix genes in limb bud mesenchymal cells in micromass culture. Interestingly, the treatments disrupted the peripheral definition and border of the cartilage nodules in such a way that many nodules overgrew and fused with each other into large amorphous cartilaginous masses. Interference with HS function reduced the physical association and interactions of BMP2 with HS and increased the cell responsiveness to endogenous and exogenous BMP proteins. In sum, Ext genes and HS are needed to establish and maintain perichondrium's phenotype and border function, restrain pro-chondrogenic signaling proteins including BMPs, and restrict chondrogenesis. Alterations in these mechanisms may contribute to exostosis formation in HME, particularly at the expense of regions rich in progenitor cells including the groove of Ranvier. Copyright © 2013 Elsevier Inc. All rights reserved.

Brain Morphometry on Congenital Hand Deformities based on Teichmüller Space Theory.

PubMed

Peng, Hao; Wang, Xu; Duan, Ye; Frey, Scott H; Gu, Xianfeng

2015-01-01

Congenital Hand Deformities (CHD) are usually occurred between fourth and eighth week after the embryo is formed. Failure of the transformation from arm bud cells to upper limb can lead to an abnormal appearing/functioning upper extremity which is presented at birth. Some causes are linked to genetics while others are affected by the environment, and the rest have remained unknown. CHD patients develop prehension through the use of their hands, which affect the brain as time passes. In recent years, CHD have gain increasing attention and researches have been conducted on CHD, both surgically and psychologically. However, the impacts of CHD on brain structure are not well-understood so far. Here, we propose a novel approach to apply Teichmüller space theory and conformal welding method to study brain morphometry in CHD patients. Conformal welding signature reflects the geometric relations among different functional areas on the cortex surface, which is intrinsic to the Riemannian metric, invariant under conformal deformation, and encodes complete information of the functional area boundaries. The computational algorithm is based on discrete surface Ricci flow, which has theoretic guarantees for the existence and uniqueness of the solutions. In practice, discrete Ricci flow is equivalent to a convex optimization problem, therefore has high numerically stability. In this paper, we compute the signatures of contours on general 3D surfaces with surface Ricci flow method, which encodes both global and local surface contour information. Then we evaluated the signatures of pre-central and post-central gyrus on healthy control and CHD subjects for analyzing brain cortical morphometry. Preliminary experimental results from 3D MRI data of CHD/control data demonstrate the effectiveness of our method. The statistical comparison between left and right brain gives us a better understanding on brain morphometry of subjects with Congenital Hand Deformities, in particular, missing the distal part of the upper limb.

Growth factors FGF8 and FGF2 and their receptor FGFR1, transcriptional factors Msx-1 and MSX-2, and apoptotic factors p19 and RIP5 participate in the early human limb development.

PubMed

Becic, Tina; Kero, Darko; Vukojevic, Katarina; Mardesic, Snjezana; Saraga-Babic, Mirna

2018-04-01

The expression pattern of fibroblast growth factors FGF8 and FGF2 and their receptor FGFR1, transcription factors MSX-1 and MSX-2, as well as cell proliferation (Ki-67) and cell death associated caspase-3, p19 and RIP5 factors were analyzed in histological sections of eight 4th-9th-weeks developing human limbs by immunohistochemistry and semi-thin sectioning. Increasing expression of all analyzed factors (except FGF8) characterized both the multilayered human apical ectodermal ridge (AER), sub-ridge mesenchyme (progress zone) and chondrocytes in developing human limbs. While cytoplasmic co-expression of MSX-1 and MSX-2 was observed in both limb epithelium and mesenchyme, p19 displayed strong cytoplasmic expression in non-proliferating cells. Nuclear expression of Ki-67 proliferating cells, and partly of MSX-1 and MSX-2 was detected in the whole limb primordium. Strong expression of factors p19 and RIP5, both in the AER and mesenchyme of human developing limbs indicates their possible involvement in control of cell senescence and cell death. In contrast to animal studies, expression of FGFR1 in the surface ectoderm and p19 in the whole limb primordium might reflect interspecies differences in limb morphology. Expression of FGF2 and downstream RIP5 gene, and transcription factors Msx-1 and MSX-2 did not show human-specific changes in expression pattern. Based on their spatio-temporal expression during human limb development, our study indicates role of FGFs and Msx genes in stimulation of cell proliferation, limb outgrowth, digit elongation and separation, and additionally MSX-2 in control of vasculogenesis. The cascade of orchestrated gene expressions, including the analyzed developmental factors, jointly contribute to the complex human limb development. Copyright © 2018 Elsevier GmbH. All rights reserved.

Chronological Sequence of Leaf Phenology, Xylem and Phloem Formation and Sap Flow of Quercus pubescens from Abandoned Karst Grasslands

PubMed Central

Lavrič, Martina; Eler, Klemen; Ferlan, Mitja; Vodnik, Dominik; Gričar, Jožica

2017-01-01

Intra-annual variations in leaf development, radial growth, including the phloem part, and sap flow have rarely been studied in deciduous trees from drought-prone environments. In order to understand better the chronological order and temporal course of these processes, we monitored leaf phenology, xylem and phloem formation and sap flow in Quercus pubescens from abandoned karst grasslands in Slovenia during the growing season of 2014. We found that the initial earlywood vessel formation started before bud opening at the beginning of April. Buds started to open in the second half of April and full leaf unfolding occurred by the end of May. LAI values increased correspondingly with leaf development. About 28% of xylem and 22% of phloem annual increment were formed by the time of bud break. Initial earlywood vessels were fully lignified and ready for water transport, indicating that they are essential to provide hydraulic conductivity for axial water flow during leaf development. Sap flow became active and increasing contemporarily with leaf development and LAI values. Similar early spring patterns of xylem sap flow and LAI denoted that water transport in oaks broadly followed canopy leaf area development. In the initial 3 weeks of radial growth, phloem growth preceded that of xylem, indicating its priority over xylem at the beginning of the growing season. This may be related to the fact that after bud break, the developing foliage is a very large sink for carbohydrates but, at the same time, represents a small transpirational area. Whether the interdependence of the chronological sequence of the studied processes is fixed in Q. pubescens needs to be confirmed with more data and several years of analyses, although the ‘correct sequence’ of processes is essential for synchronized plant performance and response to environmental stress. PMID:28321232

High-throughput sequencing of small RNAs and analysis of differentially expressed microRNAs associated with pistil development in Japanese apricot

PubMed Central

2012-01-01

Background MicroRNAs (miRNAs) are a class of endogenous, small, non-coding RNAs that regulate gene expression by mediating gene silencing at transcriptional and post-transcriptional levels in high plants. However, the diversity of miRNAs and their roles in floral development in Japanese apricot (Prunus mume Sieb. et Zucc) remains largely unexplored. Imperfect flowers with pistil abortion seriously decrease production yields. To understand the role of miRNAs in pistil development, pistil development-related miRNAs were identified by Solexa sequencing in Japanese apricot. Results Solexa sequencing was used to identify and quantitatively profile small RNAs from perfect and imperfect flower buds of Japanese apricot. A total of 22,561,972 and 24,952,690 reads were sequenced from two small RNA libraries constructed from perfect and imperfect flower buds, respectively. Sixty-one known miRNAs, belonging to 24 families, were identified. Comparative profiling revealed that seven known miRNAs exhibited significant differential expression between perfect and imperfect flower buds. A total of 61 potentially novel miRNAs/new members of known miRNA families were also identified by the presence of mature miRNAs and corresponding miRNA*s in the sRNA libraries. Comparative analysis showed that six potentially novel miRNAs were differentially expressed between perfect and imperfect flower buds. Target predictions of the 13 differentially expressed miRNAs resulted in 212 target genes. Gene ontology (GO) annotation revealed that high-ranking miRNA target genes are those implicated in the developmental process, the regulation of transcription and response to stress. Conclusions This study represents the first comparative identification of miRNAomes between perfect and imperfect Japanese apricot flowers. Seven known miRNAs and six potentially novel miRNAs associated with pistil development were identified, using high-throughput sequencing of small RNAs. The findings, both computationally and experimentally, provide valuable information for further functional characterisation of miRNAs associated with pistil development in plants. PMID:22863067

Taste buds and nerve fibers in the rat larynx: an ultrastructural and immunohistochemical study.

PubMed

Nishijima, Kazutoshi; Atoji, Yasuro

2004-09-01

We investigated the rat laryngeal taste buds and their innervation by electron microscopy and immunohistochemical methods. Taste buds were densely arranged in the surface facing the laryngeal cavity of the epiglottis, the aryepiglottic fold, and the cuneiform process of the arytenoid cartilages. The cells of the buds were classified into types I, II, III, and basal cells, the ultrastucture of which was almost the same as that previously reported in lingual taste buds. The type III cells that had synaptic contacts with nerve fibers were considered to be sensory cells. Immunohistochemical analysis revealed thick calbindin D28k-immunoreactive fibers and thin varicose fibers immunoreactive for calcitonin gene-related peptide or substance P in and around the taste bud. Serotonin-immunoreactive cells were also observed here. The results revealed the innervation pattern of laryngeal taste buds to be the same as that in lingual taste buds. Carbonic anhydrase (CA) is known to catalyze the hydration of CO2 and dehydration of H2CO3, and seems to be essential in CO2 reception. Immunoreactivity for CAI was detected in slender cells and that for CAIII was observed in barrel-like cells in the laryngeal taste buds. The pH-sensitive inward rectifier K+ (Kir) channel in the cell membrane may be involved in CO2 reception as well. CAII-reactive cells were also reactive to Kir4.1, PGP 9.5 and serotonin. Our results indicated that CAII and Kir4.1 are located in type III cells of the laryngeal taste buds, and supported the idea that the buds may be involved in the recognition of CO2.

Brain-derived neurotrophic factor-, neurotrophin-3-, and tyrosine kinase receptor-like immunoreactivity in lingual taste bud fields of mature hamster.

PubMed

Ganchrow, Donald; Ganchrow, Judith R; Verdin-Alcazar, Mary; Whitehead, Mark C

2003-01-01

The neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), as well as their respective tyrosine kinase (Trk) receptors, TrkB and TrkC, influence peripheral target cell innervation, survival, and proliferation. In the mature taste system the role of neurotrophins and their receptors is not known. The mature hamster is an intriguing model because anterior lingual fungiform, unlike posterior lingual foliate and circumvallate, taste buds survive denervation. In light of this difference, we examined whether the degree of neurotrophin- or neurotrophin receptor-like immunoreactivity (IR) normally differs among lingual gemmal fields. In single- and double-labeled immunofluorescent experiments, 3,209 taste bud sections (profiles) from 13 hamsters were examined for immunopositive gemmal cells or nerve fibers using antibodies to BDNF and NT-3, their respective receptors TrkB and TrkC, and the neural marker ubiquitin c-terminal hydrolase L-1 [protein gene product (PGP) 9.5]. In each gemmal field, more than 75% of taste bud profiles showed immunopositivity to BDNF, NT-3, and TrkB. Across bud fields, BDNF-, TrkB-, and BDNF/TrkB-like IR, as well as PGP 9.5 and PGP 9.5/BDNF-like IR in centrally located, fungiform bud cells was greater (P < 0.0001 to P < 0.002) than in circumvallate or foliate buds. Within bud fields, the number of BDNF-like, labeled bud cells/bud profile was greater than that for NT-3-like IR in fungiform (P < 0.0002) and foliate (P < 0.0001) buds. TrkC was immunonegative in gemmal cells. The average density of TrkB- and TrkC-like fiber IR was more pronounced in fungiform than posterior gemmal-bearing papillae. Thus, fungiform papillae, whose taste buds are least affected by denervation, exhibit specific neurotrophin and receptor enrichment. Copyright 2002 Wiley-Liss, Inc.

Therapeutic equivalence of budesonide/formoterol delivered via breath-actuated inhaler vs pMDI.

PubMed

Murphy, Kevin R; Dhand, Rajiv; Trudo, Frank; Uryniak, Tom; Aggarwal, Ajay; Eckerwall, Göran

2015-02-01

To assess equivalence of twice daily (bid) budesonide/formoterol (BUD/FM) 160/4.5 μg via breath-actuated metered-dose inhaler (BAI) versus pressurized metered-dose inhaler (pMDI). This 12-week, double-blind, multicenter, parallel-group study, randomized adolescents and adults (aged ≥12 years) with asthma (and ≥3 months daily use of inhaled corticosteroids) to BUD/FM BAI 2 × 160/4.5 μg bid, BUD/FM pMDI 2 × 160/4.5 μg bid, or BUD pMDI 2 × 160 μg bid. Inclusion required prebronchodilator forced expiratory volume in one second (FEV1) ≥45 to ≤85% predicted, and reversibility of ≥12% in FEV1 (ages 12 to <18 years) or ≥12% and 200 mL (ages ≥18 years). Confirmation that 60-min postdose FEV1 response to BUD/FM pMDI was superior to BUD pMDI was required before equivalence testing. Therapeutic equivalence was shown by treatment effect ratio of BUD/FM BAI vs BUD/FM pMDI on 60-min postdose FEV1 and predose FEV1 within confidence intervals (CIs) of 80-125%. Mean age of 214 randomized patients was 42.7 years. BUD/FM pMDI was superior to BUD pMDI (60-min postdose FEV1 treatment effect ratio, 1.10; 95% CI, 1.06-1.14; p < 0.001). Treatment effect ratios for BUD/FM BAI versus pMDI for 60-min postdose FEV1 (1.01; 95% CI, 0.97-1.05) and predose FEV1 (1.03; 95% CI, 0.99-1.08) were within predetermined CIs for therapeutic equivalence. Adverse event profiles, tolerability, and patient-reported ease of use were similar. BUD/FM 2 × 160/4.5 μg bid BAI is therapeutically equivalent to BUD/FM conventional pMDI. The introduction of BUD/FM BAI would expand options for delivering inhaled corticosteroid/long-acting β2-agonist combination therapy to patients with moderate-to-severe asthma. ClinicalTrials.gov NCT01360021. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Studies on flower initiation of Super-Dwarf wheat under stress conditions simulating those on the Space Station, Mir

NASA Technical Reports Server (NTRS)

Jiang, L.; Salisbury, F. B.; Campbell, W. F.; Carman, J. G.; Nan, R.

1998-01-01

Super-Dwarf wheat plants were grown in growth chambers under 12 treatments with three photoperiods (18 h, 21 h, 24 h) and four carbon dioxide (CO2) levels (360, 1,200, 3,000 and 7,000 micromoles mol-1). Carbon dioxide concentrations affected flower initiation rates of Super-Dwarf wheat. The optimum CO2 level for flower initiation and development was 1,200 micromoles mol-1. Super-optimum CO2 levels delayed flower initiation, but did not decrease final flower bud number per head. Longer photoperiods not only accelerated flower initiation rates, but also decreased deleterious effects of super-optimum CO2. Flower bud size and head length at the same developmental stage were larger under longer photoperiods, but final flower bud number was not affected by photoperiod.

Bioinformatic investigation of the role of ubiquitins in cucumber flower morphogenesis

NASA Astrophysics Data System (ADS)

Pawełkowicz, Magdalena; Osipowski, Paweł; Wojcieszek, Michał; Kowalczuk, Cezary; PlÄ der, Wojciech; Przybecki, Zbigniew

2016-09-01

Three cDNA clones were used to screen cucumber genome in order to find genes and proteins. Functional annotation reveals that they are correlated with ubiquitination pathways. Various bioinformatics tools were used to screen and check protein sequences features such as: the presence of specific domains, transmembrane regions, cleavage site and cellular placement. The computational analysis for promotor region shows many binding sites for transcription factors, which could regulate the expression of genes. In order to check gene expression levels in developing flower buds of monoecious (B10) and gynoecious (2gg) cucumber lines, the real - time PCR technique was applied. The expression was checked for the whole buds and only for the 3rd and 4th whorls of bud when generative organ are form which were obtained by Laser Capture Microdissection (LCM) technique.

Standardized Approach to Quantitatively Measure Residual Limb Skin Health in Individuals with Lower Limb Amputation.

PubMed

Rink, Cameron L; Wernke, Matthew M; Powell, Heather M; Tornero, Mark; Gnyawali, Surya C; Schroeder, Ryan M; Kim, Jayne Y; Denune, Jeffrey A; Albury, Alexander W; Gordillo, Gayle M; Colvin, James M; Sen, Chandan K

2017-07-01

Objective: (1) Develop a standardized approach to quantitatively measure residual limb skin health. (2) Report reference residual limb skin health values in people with transtibial and transfemoral amputation. Approach: Residual limb health outcomes in individuals with transtibial ( n  = 5) and transfemoral ( n  = 5) amputation were compared to able-limb controls ( n  = 4) using noninvasive imaging (hyperspectral imaging and laser speckle flowmetry) and probe-based approaches (laser doppler flowmetry, transcutaneous oxygen, transepidermal water loss, surface electrical capacitance). Results: A standardized methodology that employs noninvasive imaging and probe-based approaches to measure residual limb skin health are described. Compared to able-limb controls, individuals with transtibial and transfemoral amputation have significantly lower transcutaneous oxygen tension, higher transepidermal water loss, and higher surface electrical capacitance in the residual limb. Innovation: Residual limb health as a critical component of prosthesis rehabilitation for individuals with lower limb amputation is understudied in part due to a lack of clinical measures. Here, we present a standardized approach to measure residual limb health in people with transtibial and transfemoral amputation. Conclusion: Technology advances in noninvasive imaging and probe-based measures are leveraged to develop a standardized approach to quantitatively measure residual limb health in individuals with lower limb loss. Compared to able-limb controls, resting residual limb physiology in people that have had transfemoral or transtibial amputation is characterized by lower transcutaneous oxygen tension and poorer skin barrier function.

Differential expression of a BMP4 reporter allele in anterior fungiform versus posterior circumvallate taste buds of mice.

PubMed

Nguyen, Ha M; Barlow, Linda A

2010-10-13

Bone Morphogenetic Protein 4 (BMP4) is a diffusible factor which regulates embryonic taste organ development. However, the role of BMP4 in taste buds of adult mice is unknown. We utilized transgenic mice with LacZ under the control of the BMP4 promoter to reveal the expression of BMP4 in the tongues of adult mice. Further we evaluate the pattern of BMP4 expression with that of markers of specific taste bud cell types and cell proliferation to define and compare the cell populations expressing BMP4 in anterior (fungiform papillae) and posterior (circumvallate papilla) tongue. BMP4 is expressed in adult fungiform and circumvallate papillae, i.e., lingual structures composed of non-taste epithelium and taste buds. Unexpectedly, we find both differences and similarities with respect to expression of BMP4-driven ß-galactosidase. In circumvallate papillae, many fusiform cells within taste buds are BMP4-ß-gal positive. Further, a low percentage of BMP4-expressing cells within circumvallate taste buds is immunopositive for markers of each of the three differentiated taste cell types (I, II and III). BMP4-positive intragemmal cells also expressed a putative marker of immature taste cells, Sox2, and consistent with this finding, intragemmal cells expressed BMP4-ß-gal within 24 hours after their final mitosis, as determined by BrdU birthdating. By contrast, in fungiform papillae, BMP4-ß-gal positive cells are never encountered within taste buds. However, in both circumvallate and fungiform papillae, BMP4-ß-gal expressing cells are located in the perigemmal region, comprising basal and edge epithelial cells adjacent to taste buds proper. This region houses the proliferative cell population that gives rise to adult taste cells. However, perigemmal BMP4-ß-gal cells appear mitotically silent in both fungiform and circumvallate taste papillae, as we do not find evidence of their active proliferation using cell cycle immunomarkers and BrdU birthdating. Our data suggest that intragemmal BMP4-ß-gal cells in circumvallate papillae are immature taste cells which eventually differentiate into each of the 3 taste cell types, whereas perigemmal BMP4-ß-gal cells in both circumvallate and fungiform papillae may be slow cycling stem cells, or belong to the stem cell niche to regulate taste cell renewal from the proliferative cell population.

Changes in expression of the lysosomal membrane glycoprotein, LAMP-1 in interdigital regions during embryonic mouse limb development, in vivo and in vitro.

PubMed

Stewart, S; Yi, S; Kassabian, G; Mayo, M; Sank, A; Shuler, C

2000-06-01

Syndactyly, a failure of the digits to separate into individual units, affects about 8 to 9 per 1000 newborns and results from an aberration of the normal development of the interdigital tissues. Limb digit separation is the result of programmed cell death (apoptosis). Lysosomes play a role in the process of cell self-destruction. Our experiment was designed to test the hypothesis that the intensity of interdigital lysosomes increases during the separation of digits in vivo and in vitro. The primary mouse monoclonal antibody, 1D4B, detects the presence of lysosomes by identifying the LAMP-1 glycoprotein on the lysosome cell membrane. In our experiment this antibody immunodetected interdigital lysosome proteins in serial sections of limbs from Swiss-Webster mouse embryos, gestational ages E12.5 through E15, key developmental stages for digit separation. Digit separation was associated with an increase in intensity of lysosomal protein staining. In E12.5 limbs, the presence of lysosomes was enriched in the distal aspect of the interdigital tissue. However, the number of lysosomes markedly increased in the E13 and E14 limbs, including the entire length and width of the interdigital tissue in the E14 limbs. This lysosomal protein presence in E14 limbs was significant compared to E12.5, E13, and E15 limbs. By day 12.5, the mouse embryo limb is committed to digit separation. Addition of retinoic acid to the culture medium of limbs earlier in development, such as E12, results in induction of the process of digit separation. Cultured E12 limbs that did not receive an addition of retinoic acid, did not show digit separation. We conclude that in the limb development process, the enrichment in interdigit LAMP-1 proteins, may indicate a relationship between lysosomes, apoptosis, and digit separation. We also conclude that retinoic acid has an important role in digit separation in vivo, as shown in limb development, and demonstrated through the addition of retinoic acid to media of cultured tissues.

Probability of Regenerating a Normal Limb After Bite Injury in the Mexican Axolotl (Ambystoma mexicanum).

PubMed

Thompson, Sierra; Muzinic, Laura; Muzinic, Christopher; Niemiller, Matthew L; Voss, S Randal

2014-06-01

Multiple factors are thought to cause limb abnormalities in amphibian populations by altering processes of limb development and regeneration. We examined adult and juvenile axolotls ( Ambystoma mexicanum ) in the Ambystoma Genetic Stock Center (AGSC) for limb and digit abnormalities to investigate the probability of normal regeneration after bite injury. We observed that 80% of larval salamanders show evidence of bite injury at the time of transition from group housing to solitary housing. Among 717 adult axolotls that were surveyed, which included solitary-housed males and group-housed females, approximately half presented abnormalities, including examples of extra or missing digits and limbs, fused digits, and digits growing from atypical anatomical positions. Bite injury likely explains these limb defects, and not abnormal development, because limbs with normal anatomy regenerated after performing rostral amputations. We infer that only 43% of AGSC larvae will present four anatomically normal looking adult limbs after incurring a bite injury. Our results show regeneration of normal limb anatomy to be less than perfect after bite injury.

A nuclear factor-κB signaling pathway via protein kinase C δ regulates replication of respiratory syncytial virus in polarized normal human nasal epithelial cells

PubMed Central

Masaki, Tomoyuki; Kojima, Takashi; Okabayashi, Tamaki; Ogasawara, Noriko; Ohkuni, Tsuyoshi; Obata, Kazufumi; Takasawa, Akira; Murata, Masaki; Tanaka, Satoshi; Hirakawa, Satoshi; Fuchimoto, Jun; Ninomiya, Takafumi; Fujii, Nobuhiro; Tsutsumi, Hiroyuki; Himi, Tetsuo; Sawada, Norimasa

2011-01-01

Respiratory syncytial virus (RSV) is the major cause of bronchitis, asthma, and severe lower respiratory tract disease in infants and young children. The airway epithelium, which has a well-developed barrier regulated by tight junctions, is the first line of defense during respiratory virus infection. In upper airway human nasal epithelial cells (HNECs), however, the primary site of RSV infection, the mechanisms of replication and budding of RSV, and the epithelial cell responses, including the tight junctional barrier, remain unknown. To investigate the detailed mechanisms of replication and budding of RSV in HNECs and the epithelial cell responses, we established an RSV-infected model using human telomerase reverse transcriptase–-transfected HNECs. We first found that the expression and barrier function of tight junction molecules claudin-4 and occludin were markedly induced together with production of proinflammatory cytokines interleukin 8 and tumor necrosis factor-α in HNECs after RSV infection, and the induction of tight junction molecules possibly contributed to budding of RSV. Furthermore, the replication and budding of RSV and the epithelial cell responses in HNECs were regulated via a protein kinase C δ/hypoxia-inducible factor-1α/nuclear factor-κB pathway. The control of this pathway in HNECs may be useful not only for prevention of replication and budding of RSV, but also in therapy for RSV-induced respiratory pathogenesis. PMID:21562222

Renal development: a complex process dependent on inductive interaction.

PubMed

Upadhyay, Kiran K; Silverstein, Douglas M

2014-01-01

Renal development begins in-utero and continues throughout childhood. Almost one-third of all developmental anomalies include structural or functional abnormalities of the urinary tract. There are three main phases of in-utero renal development: Pronephros, Mesonephros and Metanephros. Within three weeks of gestation, paired pronephri appear. A series of tubules called nephrotomes fuse with the pronephric duct. The pronephros elongates and induces the nearby mesoderm, forming the mesonephric (Woffian) duct. The metanephros is the precursor of the mature kidney that originates from the ureteric bud and the metanephric mesoderm (blastema) by 5 weeks of gestation. The interaction between these two components is a reciprocal process, resulting in the formation of a mature kidney. The ureteric bud forms the major and minor calyces, and the collecting tubules while the metanephrogenic blastema develops into the renal tubules and glomeruli. In humans, all of the nephrons are formed by 32 to 36 weeks of gestation. Simultaneously, the lower urinary tract develops from the vesico urethral canal, ureteric bud and mesonephric duct. In utero, ureters deliver urine from the kidney to the bladder, thereby creating amniotic fluid. Transcription factors, extracellular matrix glycoproteins, signaling molecules and receptors are the key players in normal renal development. Many medications (e.g., aminoglycosides, cyclooxygenase inhibitors, substances that affect the renin-angiotensin aldosterone system) also impact renal development by altering the expression of growth factors, matrix regulators or receptors. Thus, tight regulation and coordinated processes are crucial for normal renal development.

Fruit load induces changes in global gene expression and in abscisic acid (ABA) and indole acetic acid (IAA) homeostasis in citrus buds

PubMed Central

Shalom, Liron; Samuels, Sivan; Zur, Naftali; Shlizerman, Lyudmila; Doron-Faigenboim, Adi; Blumwald, Eduardo; Sadka, Avi

2014-01-01

Many fruit trees undergo cycles of heavy fruit load (ON-Crop) in one year, followed by low fruit load (OFF-Crop) the following year, a phenomenon known as alternate bearing (AB). The mechanism by which fruit load affects flowering induction during the following year (return bloom) is still unclear. Although not proven, it is commonly accepted that the fruit or an organ which senses fruit presence generates an inhibitory signal that moves into the bud and inhibits apical meristem transition. Indeed, fruit removal from ON-Crop trees (de-fruiting) induces return bloom. Identification of regulatory or metabolic processes modified in the bud in association with altered fruit load might shed light on the nature of the AB signalling process. The bud transcriptome of de-fruited citrus trees was compared with those of ON- and OFF-Crop trees. Fruit removal resulted in relatively rapid changes in global gene expression, including induction of photosynthetic genes and proteins. Altered regulatory mechanisms included abscisic acid (ABA) metabolism and auxin polar transport. Genes of ABA biosynthesis were induced; however, hormone analyses showed that the ABA level was reduced in OFF-Crop buds and in buds shortly following fruit removal. Additionally, genes associated with Ca2+-dependent auxin polar transport were remarkably induced in buds of OFF-Crop and de-fruited trees. Hormone analyses showed that auxin levels were reduced in these buds as compared with ON-Crop buds. In view of the auxin transport autoinhibition theory, the possibility that auxin distribution plays a role in determining bud fate is discussed. PMID:24706719

A Growing Stem Inhibits Bud Outgrowth - The Overlooked Theory of Apical Dominance.

PubMed

Kebrom, Tesfamichael H

2017-01-01

Three theories of apical dominance, direct, diversion, and indirect, were proposed in the 1930s to explain how auxin synthesized in the shoot apex might inhibit axillary bud outgrowth, and thus shoot branching. The direct and diversion theories of apical dominance have been investigated in detail, and they are replaced with the current auxin transport canalization and second messenger theories, respectively. These two current theories still cannot entirely explain the phenomenon of apical dominance. Although there is ample evidence that the inhibition of bud outgrowth by auxin from the shoot apex is linked to stem elongation and highly branched auxin biosynthesis or signaling mutants are dwarf, the third theory proposed in the 1930s, the indirect theory, that explains apical dominance as auxin-induced stem growth indirectly inhibits bud outgrowth has been overlooked. The indirect theory did not propose how a growing stem might inhibit bud outgrowth. Recent discoveries indicate bud dormancy (syn. quiescence, paradormancy) in response to intrinsic and environmental factors in diverse species is linked to enhanced growth of the main shoot and reduced sugar level in the buds. Since a growing stem is a strong sink for sugars, and sugar is indispensable for shoot branching, the indirect theory of apical dominance might now be explained as auxin-induced stem growth inhibits bud outgrowth by diverting sugars away from buds. Detailed study of the indirect theory and the effect of source-sink status on dormancy and outgrowth of axillary buds will advance our knowledge of apical dominance and shoot branching in plants.

Norepinephrine is coreleased with serotonin in mouse taste buds.

PubMed

Huang, Yijen A; Maruyama, Yutaka; Roper, Stephen D

2008-12-03

ATP and serotonin (5-HT) are neurotransmitters secreted from taste bud receptor (type II) and presynaptic (type III) cells, respectively. Norepinephrine (NE) has also been proposed to be a neurotransmitter or paracrine hormone in taste buds. Yet, to date, the specific stimulus for NE release in taste buds is not well understood, and the identity of the taste cells that secrete NE is not known. Chinese hamster ovary cells were transfected with alpha(1A) adrenoceptors and loaded with fura-2 ("biosensors") to detect NE secreted from isolated mouse taste buds and taste cells. Biosensors responded to low concentrations of NE (>or=10 nm) with a reliable fura-2 signal. NE biosensors did not respond to stimulation with KCl or taste compounds. However, we recorded robust responses from NE biosensors when they were positioned against mouse circumvallate taste buds and the taste buds were stimulated with KCl (50 mm) or a mixture of taste compounds (cycloheximide, 10 microm; saccharin, 2 mm; denatonium, 1 mm; SC45647, 100 microm). NE biosensor responses evoked by stimulating taste buds were reversibly blocked by prazosin, an alpha(1A) receptor antagonist. Together, these findings indicate that taste bud cells secrete NE when they are stimulated. We isolated individual taste bud cells to identify the origin of NE release. NE was secreted only from presynaptic (type III) taste cells and not receptor (type II) cells. Stimulus-evoked NE release depended on Ca(2+) in the bathing medium. Using dual biosensors (sensitive to 5-HT and NE), we found all presynaptic cells secrete 5-HT and 33% corelease NE with 5-HT.

Chromatin-associated regulation of sorbitol synthesis in flower buds of peach.

PubMed

Lloret, Alba; Martínez-Fuentes, Amparo; Agustí, Manuel; Badenes, María Luisa; Ríos, Gabino

2017-11-01

PpeS6PDH gene is postulated to mediate sorbitol synthesis in flower buds of peach concomitantly with specific chromatin modifications. Perennial plants have evolved an adaptive mechanism involving protection of meristems within specialized structures named buds in order to survive low temperatures and water deprivation during winter. A seasonal period of dormancy further improves tolerance of buds to environmental stresses through specific mechanisms poorly known at the molecular level. We have shown that peach PpeS6PDH gene is down-regulated in flower buds after dormancy release, concomitantly with changes in the methylation level at specific lysine residues of histone H3 (H3K27 and H3K4) in the chromatin around the translation start site of the gene. PpeS6PDH encodes a NADPH-dependent sorbitol-6-phosphate dehydrogenase, the key enzyme for biosynthesis of sorbitol. Consistently, sorbitol accumulates in dormant buds showing higher PpeS6PDH expression. Moreover, PpeS6PDH gene expression is affected by cold and water deficit stress. Particularly, its expression is up-regulated by low temperature in buds and leaves, whereas desiccation treatment induces PpeS6PDH in buds and represses the gene in leaves. These data reveal the concurrent participation of chromatin modification mechanisms, transcriptional regulation of PpeS6PDH and sorbitol accumulation in flower buds of peach. In addition to its role as a major translocatable photosynthate in Rosaceae species, sorbitol is a widespread compatible solute and cryoprotectant, which suggests its participation in tolerance to environmental stresses in flower buds of peach.

CALHM1 ion channel mediates purinergic neurotransmission of sweet, bitter and umami tastes.

PubMed

Taruno, Akiyuki; Vingtdeux, Valérie; Ohmoto, Makoto; Ma, Zhongming; Dvoryanchikov, Gennady; Li, Ang; Adrien, Leslie; Zhao, Haitian; Leung, Sze; Abernethy, Maria; Koppel, Jeremy; Davies, Peter; Civan, Mortimer M; Chaudhari, Nirupa; Matsumoto, Ichiro; Hellekant, Göran; Tordoff, Michael G; Marambaud, Philippe; Foskett, J Kevin

2013-03-14

Recognition of sweet, bitter and umami tastes requires the non-vesicular release from taste bud cells of ATP, which acts as a neurotransmitter to activate afferent neural gustatory pathways. However, how ATP is released to fulfil this function is not fully understood. Here we show that calcium homeostasis modulator 1 (CALHM1), a voltage-gated ion channel, is indispensable for taste-stimuli-evoked ATP release from sweet-, bitter- and umami-sensing taste bud cells. Calhm1 knockout mice have severely impaired perceptions of sweet, bitter and umami compounds, whereas their recognition of sour and salty tastes remains mostly normal. Calhm1 deficiency affects taste perception without interfering with taste cell development or integrity. CALHM1 is expressed specifically in sweet/bitter/umami-sensing type II taste bud cells. Its heterologous expression induces a novel ATP permeability that releases ATP from cells in response to manipulations that activate the CALHM1 ion channel. Knockout of Calhm1 strongly reduces voltage-gated currents in type II cells and taste-evoked ATP release from taste buds without affecting the excitability of taste cells by taste stimuli. Thus, CALHM1 is a voltage-gated ATP-release channel required for sweet, bitter and umami taste perception.

Morpho-anatomy and ontogeny of the underground system of Chrysolaena simplex (Less.) Dematt. (Asteraceae).

PubMed

Santos, Vanessa S; Souza, Vinicius P; Vilhalva, Divina A A; Ferreira, Fernanda P S; Paula, José R; Rezende, Maria Helena

2016-03-01

The occurrence of thickened underground systems in Asteraceae is widely reported in the literature. Given the great complexity of underground systems, which may originate from roots, stems, or both, morpho-anatomical analyses are essential to ensure the use of correct terminology. The goals of this study were to describe the morpho-anatomy and ontogeny, investigate the occurrence of secondary metabolites and evaluate the effects of seasonality on the underground system of Chrysolaena simplex (Less.) Dematt. Samples were studied using standard protocols of plant anatomy, scanning electron microscopy, histochemical and phytochemical. The underground system of C. simplex was categorised as a rhizophore which started from cotyledonary node. In adult individuals, with rhizophores completely developed, the primary roots degenerated and adventitious radicular systems are formed. The buds in the subterranean portions promote the rhizophore growing, and form aerial stems when exposed to light. Lipophilic droplets were evident in the parenchymatous cells of the cortex and pith, endodermis and buds. Inulin-type fructans were observed in the stem axis and buds of the rhizophore. The presence of buds, secondary metabolites and the storage of fructans and lipids in the rhizophore can be seen as adaptive traits.

Paramyxovirus Assembly and Budding: Building Particles that Transmit Infections

PubMed Central

Harrison, Megan S.; Sakaguchi, Takemasa; Schmitt, Anthony P.

2010-01-01

The paramyxoviruses define a diverse group of enveloped RNA viruses that includes a number of important human and animal pathogens. Examples include human respiratory syncytial virus and the human parainfluenza viruses, which cause respiratory illnesses in young children and the elderly; measles and mumps viruses, which have caused recent resurgences of disease in developed countries; the zoonotic Hendra and Nipah viruses, which have caused several outbreaks of fatal disease in Australia and Asia; and Newcastle disease virus, which infects chickens and other avian species. Like other enveloped viruses, paramyxoviruses form particles that assemble and bud from cellular membranes, allowing the transmission of infections to new cells and hosts. Here, we review recent advances that have improved our understanding of events involved in paramyxovirus particle formation. Contributions of viral matrix proteins, glycoproteins, nucleocapsid proteins, and accessory proteins to particle formation are discussed, as well as the importance of host factor recruitment for efficient virus budding. Trafficking of viral structural components within infected cells is described, together with mechanisms that allow for the selection of specific sites on cellular membranes for the coalescence of viral proteins in preparation of bud formation and virion release. PMID:20398786

A nutrient dependant switch explains mutually exclusive existence of meiosis and mitosis initiation in budding yeast.

PubMed

Wannige, C T; Kulasiri, D; Samarasinghe, S

2014-01-21

Nutrients from living environment are vital for the survival and growth of any organism. Budding yeast diploid cells decide to grow by mitosis type cell division or decide to create unique, stress resistant spores by meiosis type cell division depending on the available nutrient conditions. To gain a molecular systems level understanding of the nutrient dependant switching between meiosis and mitosis initiation in diploid cells of budding yeast, we develop a theoretical model based on ordinary differential equations (ODEs) including the mitosis initiator and its relations to budding yeast meiosis initiation network. Our model accurately and qualitatively predicts the experimentally revealed temporal variations of related proteins under different nutrient conditions as well as the diverse mutant studies related to meiosis and mitosis initiation. Using this model, we show how the meiosis and mitosis initiators form an all-or-none type bistable switch in response to available nutrient level (mainly nitrogen). The transitions to and from meiosis or mitosis initiation states occur via saddle node bifurcation. This bidirectional switch helps the optimal usage of available nutrients and explains the mutually exclusive existence of meiosis and mitosis pathways. © 2013 Elsevier Ltd. All rights reserved.

Expression of ABA Metabolism-Related Genes Suggests Similarities and Differences Between Seed Dormancy and Bud Dormancy of Peach (Prunus persica)

PubMed Central

Wang, Dongling; Gao, Zhenzhen; Du, Peiyong; Xiao, Wei; Tan, Qiuping; Chen, Xiude; Li, Ling; Gao, Dongsheng

2016-01-01

Dormancy inhibits seed and bud growth of perennial plants until the environmental conditions are optimal for survival. Previous studies indicated that certain co-regulation pathways exist in seed and bud dormancy. In our study, we found that seed and bud dormancy are similar to some extent but show different reactions to chemical treatments that induce breaking of dormancy. Whether the abscisic acid (ABA) regulatory networks are similar in dormant peach seeds and buds is not well known; however, ABA is generally believed to play a critical role in seed and bud dormancy. In peach, some genes putatively involved in ABA synthesis and catabolism were identified and their expression patterns were studied to learn more about ABA homeostasis and the possible crosstalk between bud dormancy and seed dormancy mechanisms. The analysis demonstrated that two 9-cis-epoxycarotenoid dioxygenase-encoding genes seem to be key in regulating ABA biosynthesis to induce seed and bud dormancy. Three CYP707As play an overlapping role in controlling ABA inactivation, resulting in dormancy-release. In addition, Transcript analysis of ABA metabolism-related genes was much similar demonstrated that ABA pathways was similar in the regulation of vegetative and flower bud dormancy, whereas, expression patterns of ABA metabolism-related genes were different in seed dormancy showed that ABA pathway maybe different in regulating seed dormancy in peach. PMID:26793222

ILK modulates epithelial polarity and matrix formation in hair follicles.

PubMed

Rudkouskaya, Alena; Welch, Ian; Dagnino, Lina

2014-03-01

Hair follicle morphogenesis requires coordination of multiple signals and communication between its epithelial and mesenchymal constituents. Cell adhesion protein platforms, which include integrins and integrin-linked kinase (ILK), are critical for hair follicle formation. However, their precise contribution to this process is poorly understood. We show that in the absence of ILK, the hair follicle matrix lineage fails to develop, likely due to abnormalities in development of apical-basal cell polarity, as well as in laminin-511 and basement membrane assembly at the tip of the hair bud. These defects also result in impaired specification of hair matrix and absence of precortex and inner sheath root cell lineages. The molecular pathways affected in ILK-deficient follicles are similar to those in the absence of epidermal integrin β1 and include Wnt, but not sonic hedgehog, signaling. ILK-deficient hair buds also show abnormalities in the dermal papilla. Addition of exogenous laminin-511 restores morphological and molecular markers associated with hair matrix formation, indicating that ILK regulates hair bud cell polarity and functions upstream from laminin-511 assembly to regulate the developmental progression of hair follicles beyond the germ stage.

Msx genes are important apoptosis effectors downstream of the Shh/Gli3 pathway in the limb.

PubMed

Lallemand, Yvan; Bensoussan, Vardina; Cloment, Cécile Saint; Robert, Benoît

2009-07-15

In tetrapods, the anteroposterior (AP) patterning of the limb is under the control of the antagonistic activities of the secreted factor Sonic hedgehog (Shh) and Gli3R, the truncated repressor form of the transcription factor Gli3. In this report, we show that Msx1 and Msx2 are targets and downstream effectors of Gli3R. Consequently, in Shh null mutants, Msx genes are overexpressed and, furthermore, partially responsible for the limb phenotype. This is exemplified by the fact that reducing Msx activity in Shh mutants partially restores a normal limb development. Finally, we show that the main action of the Msx genes, in both normal and Shh(-/-) limb development, is to control cell death in the mesenchyme. We propose that, in the limb, Msx genes act downstream of the Shh/Gli3 pathway by transducing BMP signaling and that, in the absence of Shh signaling, their deregulation contributes to the extensive apoptosis that impairs limb development.

Seasonal fluxes of native grass bud banks in response to season and return interval of fire in the Northern Great Plains

USDA-ARS?s Scientific Manuscript database

Axillary buds play a fundamental role in perennial population persistence through regeneration of bud banks. However, fire could affect bud bank dynamics by altering the size and cycles of dormant and active periods. We examined impacts of fire return interval (1.5, 3, or 6 yr) and season of fire ...

Visible dormant buds as related to tree diameter and log position

Treesearch

H. Clay Smith

1967-01-01

Red oaks and yellow-poplars in a stand of second-growth cove hardwoods in West Virginia were studied to determine whether visible dormant buds are related to tree size or log position. No correlation was found between dormant buds and tree size, for either species; but yellow-poplars had a significantly greater number of buds on the upper log.

β-catenin is required for taste bud cell renewal and behavioral taste perception in adult mice

PubMed Central

Gaillard, Dany; Xu, Mingang; Millar, Sarah E.

2017-01-01

Taste stimuli are transduced by taste buds and transmitted to the brain via afferent gustatory fibers. Renewal of taste receptor cells from actively dividing progenitors is finely tuned to maintain taste sensitivity throughout life. We show that conditional β-catenin deletion in mouse taste progenitors leads to rapid depletion of progenitors and Shh+ precursors, which in turn causes taste bud loss, followed by loss of gustatory nerve fibers. In addition, our data suggest LEF1, TCF7 and Wnt3 are involved in a Wnt pathway regulatory feedback loop that controls taste cell renewal in the circumvallate papilla epithelium. Unexpectedly, taste bud decline is greater in the anterior tongue and palate than in the posterior tongue. Mutant mice with this regional pattern of taste bud loss were unable to discern sweet at any concentration, but could distinguish bitter stimuli, albeit with reduced sensitivity. Our findings are consistent with published reports wherein anterior taste buds have higher sweet sensitivity while posterior taste buds are better tuned to bitter, and suggest β-catenin plays a greater role in renewal of anterior versus posterior taste buds. PMID:28846687

Isolation of chicken taste buds for real-time Ca2+ imaging.

PubMed

Kudo, Ken-ichi; Kawabata, Fuminori; Nomura, Toumi; Aridome, Ayumi; Nishimura, Shotaro; Tabata, Shoji

2014-10-01

We isolated chicken taste buds and used a real-time Ca2+ imaging technique to investigate the functions of the taste cells. With RT-PCR, we found that isolated chicken taste bud-like cell subsets express chicken gustducin messenger RNA. Immunocytochemical techniques revealed that the cell subsets were also immunopositive for chicken gustducin. These results provided strong evidence that the isolated cell subsets contain chicken taste buds. The isolated cell subsets were spindle-shaped and approximately 61-75 μm wide and 88-98 μm long, and these characteristics are similar to those of sectional chicken taste buds. Using Ca2+ imaging, we observed the buds' response to 2 mmol/L quinine hydrochloride (a bitter substance) and their response to a mixture of 25 mmol/L L-glutamic acid monopotassium salt monohydrate and 1 mmol/L inosine 5'-monophosphate disodium salt, umami substances. The present study is the first morphological demonstration of isolated chicken taste buds, and our results indicate that the isolated taste buds were intact and functional approaches for examining the taste senses of the chicken using Ca2+ imaging can be informative. © 2014 Japanese Society of Animal Science.

The role of hormone transport and metabolism in apical dominance in oats

NASA Technical Reports Server (NTRS)

Harrison, M. A.; Kaufman, P. B.

1984-01-01

14C-benzyladenine (BA) and 14C-indole-3-acetic acid (IAA) were used to study hormone transport to the tiller bud and hormone catabolism in excised oat stem segments. Acropetal BA transport was greatest from upright stem segments to tiller buds suppressed by apical dominance. IAA, abscisic acid (ABA), and C2H4 inhibited BA transport to the tiller bud. IAA transport to the tiller bud site was inhibited by BA, C2H4, or after gravistimulation, which affected BA transport to a lesser extent than IAA transport. Multiple peaks of radioactivity were observed in 14C-BA- or 14C-IAA-treated stem segments after 9 h of transport. IAA, ABA, and C2H4 promoted BA catabolism. Auxin, ABA, and C2H4 may inhibit tiller bud release by inhibiting cytokinin transport to the tiller bud and by promoting cytokinin catabolism. Gravistimulation may promote tiller release by inhibiting IAA transport to the tiller bud and allowing cytokinins to accumulate there preferentially.