Full Text Available 17667936 Structure, function and regulation of the Toll/IL-1 receptor adaptor proteins... (.svg) (.html) (.csml) Show Structure, function and regulation of the Toll/IL-1 receptor adaptor proteins. ...PubmedID 17667936 Title Structure, function and regulation of the Toll/IL-1 receptor adaptor proteins
Giani, M.; den Otter, Wouter K.; Briels, Willem J.
The assembly of clathrin triskelia into polyhedral cages during endocytosis is regulated by adaptor proteins (APs). We explore how APs achieve this by developing coarse-grained models for clathrin and AP2, employing a Monte Carlo click interaction, to simulate their collective aggregation behavior.
Coyle, Ian P; Koh, Young-Ho; Lee, Wyan-Ching Mimi; Slind, Jessica; Fergestad, Tim; Littleton, J Troy; Ganetzky, Barry
We describe the isolation and characterization of nwk (nervous wreck), a temperature-sensitive paralytic mutant that causes excessive growth of larval neuromuscular junctions (NMJs), resulting in increased synaptic bouton number and branch formation. Ultrastructurally, mutant boutons have reduced size and fewer active zones, associated with a reduction in synaptic transmission. nwk encodes an FCH and SH3 domain-containing adaptor protein that localizes to the periactive zone of presynaptic terminals and binds to the Drosophila ortholog of Wasp (Wsp), a key regulator of actin polymerization. wsp null mutants display synaptic overgrowth similar to nwk and enhance the nwk morphological phenotype in a dose-dependent manner. Evolutionarily, Nwk belongs to a previously undescribed family of adaptor proteins that includes the human srGAPs, which regulate Rho activity downstream of Robo receptors. We propose that Nwk controls synapse morphology by regulating actin dynamics downstream of growth signals in presynaptic terminals.
Aoh, Quyen L.; Graves, Lee M.; Duncan, Mara C.
Glucose is a rich source of energy and the raw material for biomass increase. Many eukaryotic cells remodel their physiology in the presence and absence of glucose. The yeast Saccharomyces cerevisiae undergoes changes in transcription, translation, metabolism, and cell polarity in response to glucose availability. Upon glucose starvation, translation initiation and cell polarity are immediately inhibited, and then gradually recover. In this paper, we provide evidence that, as in cell polarity and translation, traffic at the trans-Golgi network (TGN) and endosomes is regulated by glucose via an unknown mechanism that depends on protein kinase A (PKA). Upon glucose withdrawal, clathrin adaptors exhibit a biphasic change in localization: they initially delocalize from the membrane within minutes and later partially recover onto membranes. Additionally, the removal of glucose induces changes in posttranslational modifications of adaptors. Ras and Gpr1 signaling pathways, which converge on PKA, are required for changes in adaptor localization and changes in posttranslational modifications. Acute inhibition of PKA demonstrates that inhibition of PKA prior to glucose withdrawal prevents several adaptor responses to starvation. This study demonstrates that PKA activity prior to glucose starvation primes membrane traffic at the TGN and endosomes in response to glucose starvation. PMID:21832155
Suzaki, Takuya; Ohneda, Masako; Toriba, Taiyo; Yoshida, Akiko; Hirano, Hiro-Yuki
CLAVATA signaling restricts stem cell identity in the shoot apical meristem (SAM) in Arabidopsis thaliana. In rice (Oryza sativa), FLORAL ORGAN NUMBER2 (FON2), closely related to CLV3, is involved as a signaling molecule in a similar pathway to negatively regulate stem cell proliferation in the floral meristem (FM). Here we show that the FON2 SPARE1 (FOS1) gene encoding a CLE protein functions along with FON2 in maintenance of the FM. In addition, FOS1 appears to be involved in maintenance of the SAM in the vegetative phase, because constitutive expression of FOS1 caused termination of the vegetative SAM. Genetic analysis revealed that FOS1 does not need FON1, the putative receptor of FON2, for its action, suggesting that FOS1 and FON2 may function in meristem maintenance as signaling molecules in independent pathways. Initially, we identified FOS1 as a suppressor that originates from O. sativa indica and suppresses the fon2 mutation in O. sativa japonica. FOS1 function in japonica appears to be compromised by a functional nucleotide polymorphism (FNP) at the putative processing site of the signal peptide. Sequence comparison of FOS1 in about 150 domesticated rice and wild rice species indicates that this FNP is present only in japonica, suggesting that redundant regulation by FOS1 and FON2 is commonplace in species in the Oryza genus. Distribution of the FNP also suggests that this mutation may have occurred during the divergence of japonica from its wild ancestor. Stem cell maintenance may be regulated by at least three negative pathways in rice, and each pathway may contribute differently to this regulation depending on the type of the meristem. This situation contrasts with that in Arabidopsis, where CLV signaling is the major single pathway in all meristems. PMID:19834537
Full Text Available CLAVATA signaling restricts stem cell identity in the shoot apical meristem (SAM in Arabidopsis thaliana. In rice (Oryza sativa, FLORAL ORGAN NUMBER2 (FON2, closely related to CLV3, is involved as a signaling molecule in a similar pathway to negatively regulate stem cell proliferation in the floral meristem (FM. Here we show that the FON2 SPARE1 (FOS1 gene encoding a CLE protein functions along with FON2 in maintenance of the FM. In addition, FOS1 appears to be involved in maintenance of the SAM in the vegetative phase, because constitutive expression of FOS1 caused termination of the vegetative SAM. Genetic analysis revealed that FOS1 does not need FON1, the putative receptor of FON2, for its action, suggesting that FOS1 and FON2 may function in meristem maintenance as signaling molecules in independent pathways. Initially, we identified FOS1 as a suppressor that originates from O. sativa indica and suppresses the fon2 mutation in O. sativa japonica. FOS1 function in japonica appears to be compromised by a functional nucleotide polymorphism (FNP at the putative processing site of the signal peptide. Sequence comparison of FOS1 in about 150 domesticated rice and wild rice species indicates that this FNP is present only in japonica, suggesting that redundant regulation by FOS1 and FON2 is commonplace in species in the Oryza genus. Distribution of the FNP also suggests that this mutation may have occurred during the divergence of japonica from its wild ancestor. Stem cell maintenance may be regulated by at least three negative pathways in rice, and each pathway may contribute differently to this regulation depending on the type of the meristem. This situation contrasts with that in Arabidopsis, where CLV signaling is the major single pathway in all meristems.
Bowman, J L; Sakai, H; Jack, T; Weigel, D; Mayer, U; Meyerowitz, E M
We describe a locus, SUPERMAN, mutations in which result in extra stamens developing at the expense of the central carpels in the Arabidopsis thaliana flower. The development of superman flowers, from initial primordium to mature flower, is described by scanning electron microscopy. The development of doubly and triply mutant strains, constructed with superman alleles and previously identified homeotic mutations that cause alterations in floral organ identity, is also described. Essentially additive phenotypes are observed in superman agamous and superman apetala2 double mutants. The epistatic relationships observed between either apetala3 or pistillata and superman alleles suggest that the SUPERMAN gene product could be a regulator of these floral homeotic genes. To test this, the expression patterns of AGAMOUS and APETALA3 were examined in superman flowers. In wild-type flowers, APETALA3 expression is restricted to the second and third whorls where it is required for the specification of petals and stamens. In contrast, in superman flowers, APETALA3 expression expands to include most of the cells that would normally constitute the fourth whorl. This ectopic APETALA3 expression is proposed to be one of the causes of the development of the extra stamens in superman flowers. The spatial pattern of AGAMOUS expression remains unaltered in superman flowers as compared to wild-type flowers. Taken together these data indicate that one of the functions of the wild-type SUPERMAN gene product is to negatively regulate APETALA3 in the fourth whorl of the flower. In addition, superman mutants exhibit a loss of determinacy of the floral meristem, an effect that appears to be mediated by the APETALA3 and PISTILLATA gene products.
Das, Pradeep; Ito, Toshiro; Wellmer, Frank; Vernoux, Teva; Dedieu, Annick; Traas, Jan; Meyerowitz, Elliot M
In Arabidopsis, the population of stem cells present in young flower buds is lost after the production of a fixed number of floral organs. The precisely timed repression of the stem cell identity gene WUSCHEL (WUS) by the floral homeotic protein AGAMOUS (AG) is a key part of this process. In this study, we report on the identification of a novel input into the process of floral stem cell regulation. We use genetics and chromatin immunoprecipitation assays to demonstrate that the bZIP transcription factor PERIANTHIA (PAN) plays a role in regulating stem cell fate by directly controlling AG expression and suggest that this activity is spatially restricted to the centermost region of the AG expression domain. These results suggest that the termination of floral stem cell fate is a multiply redundant process involving loci with unrelated floral patterning functions.
Uemura, Akira; Yamaguchi, Nobutoshi; Xu, Yifeng; Wee, WanYi; Ichihashi, Yasunori; Suzuki, Takamasa; Shibata, Arisa; Shirasu, Ken; Ito, Toshiro
Floral meristem size is redundantly controlled by CLAVATA3, AGAMOUS , and SUPERMAN in Arabidopsis. The proper regulation of floral meristem activity is key to the formation of optimally sized flowers with a fixed number of organs. In Arabidopsis thaliana, multiple regulators determine this activity. A small secreted peptide, CLAVATA3 (CLV3), functions as an important negative regulator of stem cell activity. Two transcription factors, AGAMOUS (AG) and SUPERMAN (SUP), act in different pathways to regulate the termination of floral meristem activity. Previous research has not addressed the genetic interactions among these three genes. Here, we quantified the floral developmental stage-specific phenotypic consequences of combining mutations of AG, SUP, and CLV3. Our detailed phenotypic and genetic analyses revealed that these three genes act in partially redundant pathways to coordinately modulate floral meristem sizes in a spatial and temporal manner. Analyses of the ag sup clv3 triple mutant, which developed a mass of undifferentiated cells in its flowers, allowed us to identify downstream targets of AG with roles in reproductive development and in the termination of floral meristem activity. Our study highlights the role of AG in repressing genes that are expressed in organ initial cells to control floral meristem activity.
Mary C. Halloran
Full Text Available Axon growth and branching, and development of neuronal polarity are critically dependent on proper organization and dynamics of the microtubule (MT cytoskeleton. MTs must organize with correct polarity for delivery of diverse cargos to appropriate subcellular locations, yet the molecular mechanisms regulating MT polarity remain poorly understood. Moreover, how an actively branching axon reorganizes MTs to direct their plus ends distally at branch points is unknown. We used high-speed, in vivo imaging of polymerizing MT plus ends to characterize MT dynamics in developing sensory axon arbors in zebrafish embryos. We find that axonal MTs are highly dynamic throughout development, and that the peripheral and central axons of sensory neurons show differences in MT behaviors. Furthermore, we show that Calsyntenin-1 (Clstn-1, a kinesin adaptor required for sensory axon branching, also regulates MT polarity in developing axon arbors. In wild type neurons the vast majority of MTs are directed in the correct plus-end-distal orientation from early stages of development. Loss of Clstn-1 causes an increase in MTs polymerizing in the retrograde direction. These misoriented MTs most often are found near growth cones and branch points, suggesting Clstn-1 is particularly important for organizing MT polarity at these locations. Together, our results suggest that Clstn-1, in addition to regulating kinesin-mediated cargo transport, also organizes the underlying MT highway during axon arbor development.
Cho, Sung Ki; Larue, Clayton T; Chevalier, David; Wang, Huachun; Jinn, Tsung-Luo; Zhang, Shuqun; Walker, John C
Abscission is a developmental program that results in the active shedding of infected or nonfunctional organs from a plant body. Here, we establish a signaling pathway that controls abscission in Arabidopsis thaliana from ligand, to receptors, to downstream effectors. Loss of function mutations in Inflorescence Deficient in Abscission (IDA), which encodes a predicted secreted small protein, the receptor-like protein kinases HAESA (HAE) and HAESA-like 2 (HSL2), the Mitogen-Activated Protein Kinase Kinase 4 (MKK4) and MKK5, and a dominant-negative form of Mitogen-Activated Protein Kinase 6 (MPK6) in a mpk3 mutant background all have abscission-defective phenotypes. Conversely, expression of constitutively active MKKs rescues the abscission-defective phenotype of hae hsl2 and ida plants. Additionally, in hae hsl2 and ida plants, MAP kinase activity is reduced in the receptacle, the part of the stem that holds the floral organs. Plants overexpressing IDA in a hae hsl2 background have abscission defects, indicating HAE and HSL2 are epistatic to IDA. Taken together, these results suggest that the sequential action of IDA, HAE and HSL2, and a MAP kinase cascade regulates the programmed separation of cells in the abscission zone.
Rieder, Leila E; Koreski, Kaitlin P; Boltz, Kara A; Kuzu, Guray; Urban, Jennifer A; Bowman, Sarah K; Zeidman, Anna; Jordan, William T; Tolstorukov, Michael Y; Marzluff, William F; Duronio, Robert J; Larschan, Erica N
The conserved histone locus body (HLB) assembles prior to zygotic gene activation early during development and concentrates factors into a nuclear domain of coordinated histone gene regulation. Although HLBs form specifically at replication-dependent histone loci, the cis and trans factors that target HLB components to histone genes remained unknown. Here we report that conserved GA repeat cis elements within the bidirectional histone3-histone4 promoter direct HLB formation in Drosophila In addition, the CLAMP (chromatin-linked adaptor for male-specific lethal [MSL] proteins) zinc finger protein binds these GA repeat motifs, increases chromatin accessibility, enhances histone gene transcription, and promotes HLB formation. We demonstrated previously that CLAMP also promotes the formation of another domain of coordinated gene regulation: the dosage-compensated male X chromosome. Therefore, CLAMP binding to GA repeat motifs promotes the formation of two distinct domains of coordinated gene activation located at different places in the genome. © 2017 Rieder et al.; Published by Cold Spring Harbor Laboratory Press.
Wei Sheng Chia
Full Text Available p97/Valosin-containing protein (VCP is a member of the AAA-ATPase family involved in many cellular processes including cell division, intracellular trafficking and extraction of misfolded proteins in endoplasmic reticulum-associated degradation (ERAD. It is a homohexamer with each subunit containing two tandem D1 and D2 ATPase domains and N- and C-terminal regions that function as adaptor protein binding domains. p97/VCP is directed to its many different functional pathways by associating with various adaptor proteins. The regulation of the recruitment of the adaptor proteins remains unclear. Two adaptor proteins, Ufd1/Npl4 and p47, which bind exclusively to the p97/VCP N-domain and direct p97/VCP to either ERAD-related processes or homotypic fusion of Golgi fragments, were studied here. Surface plasmon resonance biosensor-based assays allowed the study of binding kinetics in real time. In competition experiments, it was observed that in the presence of ATP, Ufd1/Npl4 was able to compete more effectively with p47 for binding to p97/VCP. By using non-hydrolysable ATP analogues and the hexameric truncated p97/N-D1 fragment, it was shown that binding rather than hydrolysis of ATP to the proximal D1 domain strengthened the Ufd1/Npl4 association with the N-domain, thus regulating the recruitment of either Ufd1/Npl4 or p47. This novel role of ATP and an assigned function to the D1 AAA-ATPase domain link the multiple functions of p97/VCP to the metabolic status of the cell.
Bowman, John L.; Sakai, Hajime; Jack, Thomas; Weigel, Detlef; Mayer, Ulrike; Meyerowitz, Elliot M.
We describe a locus, SUPERMAN, mutations in which result in extra stamens developing at the expense of the central carpels in the Arabidopsis thaliana flower. The development of superman flowers, from initial primordium to mature flower, is described by scanning electron microscopy. The development of doubly and triply mutant strains, constructed with superman alleles and previously identified homeotic mutations that cause alterations in floral organ identity, is also described. Essentially a...
Full Text Available min Immunol. 2004 Dec;16(6):409-19. (.png) (.svg) (.html) (.csml) Show The SAP family of adaptors in immune ...g) SVG File (.svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csml file with C
Bemis, Shannon M; Lee, Jin Suk; Shpak, Elena D; Torii, Keiko U
Due to the lack of cell migration, plant organogenesis relies on coordinated cell proliferation, cell growth, and differentiation. A flower possesses a complex structure, with sepals and petals constituting the perianth, and stamens and pistils where male and female gametophytes differentiate. While advances have been made in our understanding of gene regulatory networks controlling flower development, relatively little is known of how cell-cell coordination influences floral organ specification. The Arabidopsis ERECTA (ER)-family receptor kinases, ER, ER-LIKE1 (ERL1), and ERL2, regulate inflorescence architecture, organ shape, and epidermal stomatal patterning. Here it is reported that ER-family genes together regulate floral meristem organization and floral organ identity. The stem cell marker CLAVATA3 exhibits misplaced expression in the floral meristems of the er erl1 erl2 mutant. Strikingly, homeotic conversion of sepals to carpels was observed in er erl1 erl2 flowers. Consistently, ectopic expression of AGAMOUS, which determines carpel identity, was detected in er erl1 erl2 flower primordia. Among the known downstream components of ER-family receptor kinases in stomatal patterning, YODA (YDA) is also required for proper floral patterning. YDA and the ER-family show complex, synergistic genetic interactions: er erl1 erl2 yda quadruple mutant plants become extremely small, callus-like masses. While a constitutively active YDA fully rescues stomatal clustering in er erl1 erl2, it only partially rescues er erl1 erl2 flower defects. The study suggests that ER-family signalling is crucial for ensuring proper expression domains of floral meristem and floral organ identity determinants, and further implies the existence of a non-canonical downstream pathway.
Mikkelsen, Hanne B; Huizinga, Jan D; Larsen, Jytte O
the reaction of resident macrophages of the musculature to a pro-inflammatory stimulator, lipopolysaccharide (LPS). Mice were injected with LPS or saline and sacrificed after 6 hours. Whole mounts were stained with antibodies toward CD169, ionized calcium-binding adaptor molecule 1 (iba1) (microglial...... macrophages in serosa and at AP, suggesting a M2 phenotype. LPS-treatment results in an up-regulation of HO-1(pos) /CD169(neg) cells in serosa and at AP. This article is protected by copyright. All rights reserved....
Wagner, Doris; Wellmer, Frank; Dilks, Kieran; William, Dilusha; Smith, Michael R; Kumar, Prakash P; Riechmann, José Luis; Greenland, Andrew J; Meyerowitz, Elliot M
We have developed a versatile floral induction system that is based on ectopic overexpression of the transcription factor LEAFY (LFY) in callus. During shoot regeneration, flowers or floral organs are formed directly from root explants without prior formation of rosette leaves. Morphological and reporter gene analyses show that leaf-like structures are converted to floral organs in response to LFY activity. Thus, increased levels of LFY activity are sufficient to bypass normal vegetative development and to direct formation of flowers in tissue culture. We found that about half of the cultured cells respond to inducible LFY activity with a rapid upregulation of the known direct target gene of LFY, APETALA1 (AP1). This dramatic increase in the number of LFY-responsive cells compared to whole plants suggested that the tissue culture system could greatly facilitate the analysis of LFY-dependent gene regulation by genomic approaches. To test this, we monitored the gene expression changes that occur in tissue culture after activation of LFY using a flower-specific cDNA microarray. Induction of known LFY target genes was readily detected in these experiments. In addition, several other genes were identified that had not been implicated in signaling downstream of LFY before. Thus, the floral induction system is suitable for the detection of low abundance transcripts whose expression is controlled in an LFY-dependent manner.
Tang, Mingyong; Tao, Yan-Bin; Fu, Qiantang; Song, Yaling; Niu, Longjian; Xu, Zeng-Fu
Jatropha curcas seeds are an excellent biofuel feedstock, but seed yields of Jatropha are limited by its poor flowering and fruiting ability. Thus, identifying genes controlling flowering is critical for genetic improvement of seed yield. We isolated the JcLFY, a Jatropha ortholog of Arabidopsis thaliana LEAFY (LFY), and identified JcLFY function by overexpressing it in Arabidopsis and Jatropha. JcLFY is expressed in Jatropha inflorescence buds, flower buds, and carpels, with highest expression in the early developmental stage of flower buds. JcLFY overexpression induced early flowering, solitary flowers, and terminal flowers in Arabidopsis, and also rescued the delayed flowering phenotype of lfy-15, a LFY loss-of-function Arabidopsis mutant. Microarray and qPCR analysis revealed several flower identity and flower organ development genes were upregulated in JcLFY-overexpressing Arabidopsis. JcLFY overexpression in Jatropha also induced early flowering. Significant changes in inflorescence structure, floral organs, and fruit shape occurred in JcLFY co-suppressed plants in which expression of several flower identity and floral organ development genes were changed. This suggests JcLFY is involved in regulating flower identity, floral organ patterns, and fruit shape, although JcLFY function in Jatropha floral meristem determination is not as strong as that of Arabidopsis. PMID:27869146
Sawicki, Mélodie; Jacquens, Lucile; Baillieul, Fabienne; Clément, Christophe; Vaillant-Gaveau, Nathalie; Jacquard, Cédric
Carbohydrate metabolism is important in plant sexual reproduction because sugar contents are determining factors for both flower initiation and floral organ development. In woody plants, flowering represents the most energy-consuming step crucial to reproductive success. Nevertheless, in these species, the photosynthesis performed by flowers supplies the carbon required for reproduction. In grapevine (Vitis vinifera), the inflorescence has a specific status because this organ imports carbohydrates at the same time as it exports photoassimilates. In this study, fluctuations in carbohydrate metabolism were monitored by analyzing gas exchanges, photosynthetic electron transport capacity, carbohydrate contents and some activities of carbohydrate metabolism enzymes, in the inflorescences of Pinot noir and Gewurztraminer, two cultivars with a different sensitivity to coulure phenomenon. Our results showed that photosynthetic activity and carbohydrate metabolism are clearly different and differently regulated during the floral development in the two cultivars. Indeed, the regulation of the linear electron flow and the cyclic electron flow is not similar. Moreover, the regulation of PSII activity, with a higher Y(NPQ)/Y(NO) ratio in Gewurztraminer, can be correlated with the higher protection of the photosynthetic chain and consequently with the higher yield under optimal conditions of this cultivar. At least, our results showed a higher photosynthetic activity and a better protection of PSI in Pinot noir during the floral development. © 2015 Scandinavian Plant Physiology Society.
ÓMaoiléidigh, Diarmuid S; Wuest, Samuel E; Rae, Liina; Raganelli, Andrea; Ryan, Patrick T; Kwasniewska, Kamila; Das, Pradeep; Lohan, Amanda J; Loftus, Brendan; Graciet, Emmanuelle; Wellmer, Frank
The floral organ identity factor AGAMOUS (AG) is a key regulator of Arabidopsis thaliana flower development, where it is involved in the formation of the reproductive floral organs as well as in the control of meristem determinacy. To obtain insights into how AG specifies organ fate, we determined the genes and processes acting downstream of this C function regulator during early flower development and distinguished between direct and indirect effects. To this end, we combined genome-wide localization studies, gene perturbation experiments, and computational analyses. Our results demonstrate that AG controls flower development to a large extent by controlling the expression of other genes with regulatory functions, which are involved in mediating a plethora of different developmental processes. One aspect of this function is the suppression of the leaf development program in emerging floral primordia. Using trichome initiation as an example, we demonstrate that AG inhibits an important aspect of leaf development through the direct control of key regulatory genes. A comparison of the gene expression programs controlled by AG and the B function regulators APETALA3 and PISTILLATA, respectively, showed that while they control many developmental processes in conjunction, they also have marked antagonistic, as well as independent activities.
Giltiay, Natalia V.; Lu, Yi; Allman, David; Jørgensen, Trine N.; Li, Xiaoxia
The transitional stage is a key check-point for elimination of autoreactive B cells in the periphery. This selection process requires fine regulation of signals received through B-cell receptor (BCR) and B cell activating factor receptor (BAFFR). We previously identified the adaptor molecule Act1 as a negative regulator of BAFF-mediated signaling. Deficiency of Act1 in mice results in peripheral B cell hyperplasia and development of autoimmunity. In this study we demonstrate that Act1 plays a critical role in the regulation of transitional B cell survival and maturation. We found that the ratio of late-transitional (T2) to early-transitional (T1) cells was increased in spleens from Act1-deficient mice. Moreover, BAFF stimulation induced better T1 cell survival and promoted more efficient maturation of T1 cells into T2 cells ex vivo in the absence of Act1. BAFF stimulation induced higher levels of the anti-apoptotic Bcl2-member Mc1-l in Act1-deficient T1 than that in wild-type control cells, suggesting that Mcl1 might be one of the key effector molecules for BAFF-mediated survival in the Act1-deficient transitional B cells. Importantly, co-stimulation with BAFF was able to rescue Act1-deficient T1 cells from BCR-induced apoptosis more effectively than Act1-suffienct T1 B cells. Finally, by using double transgenic HEL mice, we demonstrated that Act1 deficiency can promote the maturation of HEL-specific autoreactive B cells. Taken together, our results suggest that the transitional stage is a critical point of action for Act1 in the elimination of autoreactive B cells and in the regulation of peripheral B cell homeostasis. PMID:20543113
Dietrich, J; Kastrup, J; Nielsen, B L
Several receptors are downregulated by internalization after ligand binding. Regulation of T cell receptor (TCR) expression is an important step in T cell activation, desensitization, and tolerance induction. One way T cells regulate TCR expression is by phosphorylation/dephosphorylation of the T...
Full Text Available SH2B adaptor protein family members (SH2B1-3 regulate various physiological responses through affecting signaling, gene expression, and cell adhesion. SH2B1 and SH2B2 were reported to enhance nerve growth factor (NGF-induced neuronal differentiation in PC12 cells, a well-established neuronal model system. In contrast, SH2B3 was reported to inhibit cell proliferation during the development of immune system. No study so far addresses the role of SH2B3 in the nervous system. In this study, we provide evidence suggesting that SH2B3 is expressed in the cortex of embryonic rat brain. Overexpression of SH2B3 not only inhibits NGF-induced differentiation of PC12 cells but also reduces neurite outgrowth of primary cortical neurons. SH2B3 does so by repressing NGF-induced activation of PLCγ, MEK-ERK1/2 and PI3K-AKT pathways and the expression of Egr-1. SH2B3 is capable of binding to phosphorylated NGF receptor, TrkA, as well as SH2B1β. Our data further demonstrate that overexpression of SH2B3 reduces the interaction between SH2B1β and TrkA. Consistent with this finding, overexpressing the SH2 domain of SH2B3 is sufficient to inhibit NGF-induced neurite outgrowth. Together, our data demonstrate that SH2B3, unlike the other two family members, inhibits neuronal differentiation of PC12 cells and primary cortical neurons. Its inhibitory mechanism is likely through the competition of TrkA binding with the positive-acting SH2B1 and SH2B2.
Eisinger, Kristina; Rein-Fischboeck, Lisa; Pohl, Rebekka; Meier, Elisabeth M.; Krautbauer, Sabrina; Buechler, Christa, E-mail: email@example.com
The scaffold protein alpha-syntrophin (SNTA) regulates lipolysis indicating a role in lipid homeostasis. Adipocytes are the main lipid storage cells in the body, and here, the function of SNTA has been analyzed in 3T3-L1 cells. SNTA is expressed in preadipocytes and is induced early during adipogenesis. Knock-down of SNTA in preadipocytes increases their proliferation. Proteins which are induced during adipogenesis like adiponectin and caveolin-1, and the inflammatory cytokine IL-6 are at normal levels in the mature cells differentiated from preadipocytes with low SNTA. This suggests that SNTA does neither affect differentiation nor inflammation. Expression of proteins with a role in cholesterol and triglyceride homeostasis is unchanged. Consequently, basal and epinephrine induced lipolysis as well as insulin stimulated phosphorylation of Akt and ERK1/2 are normal. Importantly, adipocytes with low SNTA form smaller lipid droplets and store less triglycerides. Stearoyl-CoA reductase and MnSOD are reduced upon SNTA knock-down but do not contribute to lower lipid levels. Oleate uptake is even increased in cells with SNTA knock-down. In summary, current data show that SNTA is involved in the expansion of lipid droplets independent of adipogenesis. Enhanced preadipocyte proliferation and capacity to store surplus fatty acids may protect adipocytes with low SNTA from lipotoxicity in obesity. - Highlights: • Alpha-syntrophin (SNTA) is expressed in 3T3-L1adipocytes. • SNTA knock-down in preadipocytes has no effect on adipogenesis. • Mature 3T3-L1 differentiated from cells with low SNTA form small lipid droplets. • SCD1 and MnSOD are reduced in adipocytes with low SNTA. • SCD1 knock-down does not alter triglyceride levels.
Kim, Jungeun; Park, June Hyun; Lim, Chan Ju; Lim, Jae Yun; Ryu, Jee-Youn; Lee, Bong-Woo; Choi, Jae-Pil; Kim, Woong Bom; Lee, Ha Yeon; Choi, Yourim; Kim, Donghyun; Hur, Cheol-Goo; Kim, Sukweon; Noh, Yoo-Sun; Shin, Chanseok; Kwon, Suk-Yoon
Roses (Rosa sp.), which belong to the family Rosaceae, are the most economically important ornamental plants--making up 30% of the floriculture market. However, given high demand for roses, rose breeding programs are limited in molecular resources which can greatly enhance and speed breeding efforts. A better understanding of important genes that contribute to important floral development and desired phenotypes will lead to improved rose cultivars. For this study, we analyzed rose miRNAs and the rose flower transcriptome in order to generate a database to expound upon current knowledge regarding regulation of important floral characteristics. A rose genetic database will enable comprehensive analysis of gene expression and regulation via miRNA among different Rosa cultivars. We produced more than 0.5 million reads from expressed sequences, totalling more than 110 million bp. From these, we generated 35,657, 31,434, 34,725, and 39,722 flower unigenes from Rosa hybrid: 'Vital', 'Maroussia', and 'Sympathy' and Rosa rugosa Thunb., respectively. The unigenes were assigned functional annotations, domains, metabolic pathways, Gene Ontology (GO) terms, Plant Ontology (PO) terms, and MIPS Functional Catalogue (FunCat) terms. Rose flower transcripts were compared with genes from whole genome sequences of Rosaceae members (apple, strawberry, and peach) and grape. We also produced approximately 40 million small RNA reads from flower tissue for Rosa, representing 267 unique miRNA tags. Among identified miRNAs, 25 of them were novel and 242 of them were conserved miRNAs. Statistical analyses of miRNA profiles revealed both shared and species-specific miRNAs, which presumably effect flower development and phenotypes. In this study, we constructed a Rose miRNA and transcriptome database, and we analyzed the miRNAs and transcriptome generated from the flower tissues of four Rosa cultivars. The database provides a comprehensive genetic resource which can be used to better understand
Wei, Bin; Han, Lei; Abbink, Truus E M; Groppelli, Elisabetta; Lim, Daina; Thaker, Youg Raj; Gao, Wei; Zhai, Rongrong; Wang, Jianhua; Lever, Andrew; Jolly, Clare; Wang, Hongyan; Rudd, Christopher E
Immune cell adaptor protein ADAP (adhesion and degranulation-promoting adaptor protein) mediates aspects of T-cell adhesion and proliferation. Despite this, a connection between ADAP and infection by the HIV-1 (human immunodeficiency virus-1) has not been explored. In this paper, we show for the first time that ADAP and its binding to SLP-76 (SH2 domain-containing leukocyte protein of 76 kDa) regulate HIV-1 infection via two distinct mechanisms and co-receptors. siRNA down-regulation of ADAP, or expression of a mutant that is defective in associating to its binding partner SLP-76 (termed M12), inhibited the propagation of HIV-1 in T-cell lines and primary human T-cells. In one step, ADAP and its binding to SLP-76 were needed for the activation of NF-κB and its transcription of the HIV-1 long terminal repeat (LTR) in cooperation with ligation of co-receptor CD28, but not LFA-1. In a second step, the ADAP-SLP-76 module cooperated with LFA-1 to regulate conjugate formation between T-cells and dendritic cells or other T-cells as well as the development of the virological synapse (VS) and viral spread between immune cells. These findings indicate that ADAP regulates two steps of HIV-1 infection cooperatively with two distinct receptors, and as such, serves as a new potential target in the blockade of HIV-1 infection.
Garafalo, Steven D; Luth, Eric S; Moss, Benjamin J; Monteiro, Michael I; Malkin, Emily; Juo, Peter
Regulation of glutamate receptor (GluR) abundance at synapses by clathrin-mediated endocytosis can control synaptic strength and plasticity. We take advantage of viable, null mutations in subunits of the clathrin adaptor protein 2 (AP2) complex in Caenorhabditis elegans to characterize the in vivo role of AP2 in GluR trafficking. In contrast to our predictions for an endocytic adaptor, we found that levels of the GluR GLR-1 are decreased at synapses in the ventral nerve cord (VNC) of animals with mutations in the AP2 subunits APM-2/μ2, APA-2/α, or APS-2/σ2. Rescue experiments indicate that APM-2/μ2 functions in glr-1-expressing interneurons and the mature nervous system to promote GLR-1 levels in the VNC. Genetic analyses suggest that APM-2/μ2 acts upstream of GLR-1 endocytosis in the VNC. Consistent with this, GLR-1 accumulates in cell bodies of apm-2 mutants. However, GLR-1 does not appear to accumulate at the plasma membrane of the cell body as expected, but instead accumulates in intracellular compartments including Syntaxin-13- and RAB-14-labeled endosomes. This study reveals a novel role for the AP2 clathrin adaptor in promoting the abundance of GluRs at synapses in vivo, and implicates AP2 in the regulation of GluR trafficking at an early step in the secretory pathway. © 2015 Garafalo 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).
Full Text Available Abstract Background Roses (Rosa sp., which belong to the family Rosaceae, are the most economically important ornamental plants—making up 30% of the floriculture market. However, given high demand for roses, rose breeding programs are limited in molecular resources which can greatly enhance and speed breeding efforts. A better understanding of important genes that contribute to important floral development and desired phenotypes will lead to improved rose cultivars. For this study, we analyzed rose miRNAs and the rose flower transcriptome in order to generate a database to expound upon current knowledge regarding regulation of important floral characteristics. A rose genetic database will enable comprehensive analysis of gene expression and regulation via miRNA among different Rosa cultivars. Results We produced more than 0.5 million reads from expressed sequences, totalling more than 110 million bp. From these, we generated 35,657, 31,434, 34,725, and 39,722 flower unigenes from Rosa hybrid: ‘Vital’, ‘Maroussia’, and ‘Sympathy’ and Rosa rugosa Thunb. , respectively. The unigenes were assigned functional annotations, domains, metabolic pathways, Gene Ontology (GO terms, Plant Ontology (PO terms, and MIPS Functional Catalogue (FunCat terms. Rose flower transcripts were compared with genes from whole genome sequences of Rosaceae members (apple, strawberry, and peach and grape. We also produced approximately 40 million small RNA reads from flower tissue for Rosa, representing 267 unique miRNA tags. Among identified miRNAs, 25 of them were novel and 242 of them were conserved miRNAs. Statistical analyses of miRNA profiles revealed both shared and species-specific miRNAs, which presumably effect flower development and phenotypes. Conclusions In this study, we constructed a Rose miRNA and transcriptome database, and we analyzed the miRNAs and transcriptome generated from the flower tissues of four Rosa cultivars. The database provides a
Ó’Maoiléidigh, Diarmuid S.; Wuest, Samuel E.; Rae, Liina; Raganelli, Andrea; Ryan, Patrick T.; Kwaśniewska, Kamila; Das, Pradeep; Lohan, Amanda J.; Loftus, Brendan; Graciet, Emmanuelle; Wellmer, Frank
The floral organ identity factor AGAMOUS (AG) is a key regulator of Arabidopsis thaliana flower development, where it is involved in the formation of the reproductive floral organs as well as in the control of meristem determinacy. To obtain insights into how AG specifies organ fate, we determined the genes and processes acting downstream of this C function regulator during early flower development and distinguished between direct and indirect effects. To this end, we combined genome-wide localization studies, gene perturbation experiments, and computational analyses. Our results demonstrate that AG controls flower development to a large extent by controlling the expression of other genes with regulatory functions, which are involved in mediating a plethora of different developmental processes. One aspect of this function is the suppression of the leaf development program in emerging floral primordia. Using trichome initiation as an example, we demonstrate that AG inhibits an important aspect of leaf development through the direct control of key regulatory genes. A comparison of the gene expression programs controlled by AG and the B function regulators APETALA3 and PISTILLATA, respectively, showed that while they control many developmental processes in conjunction, they also have marked antagonistic, as well as independent activities. PMID:23821642
Taylor, Scott A.; Hofer, Julie M.I.; Murfet, Ian C.; Sollinger, John D.; Singer, Susan R.; Knox, Maggie R.; Ellis, T.H. Noel
SQUAMOSA and APETALA1 are floral meristem identity genes from snapdragon (Antirrhinum majus) and Arabidopsis, respectively. Here, we characterize the floral meristem identity mutation proliferating inflorescence meristem (pim) from pea (Pisum sativum) and show that it corresponds to a defect in the PEAM4 gene, a homolog of SQUAMOSA and APETALA1. The PEAM4 coding region was deleted in the pim-1 allele, and this deletion cosegregated with the pim-1 mutant phenotype. The pim-2 allele carried a nucleotide substitution at a predicted 5′ splice site that resulted in mis-splicing of pim-2 mRNA. PCR products corresponding to unspliced and exon-skipped mRNA species were observed. The pim-1 and pim-2 mutations delayed floral meristem specification and altered floral morphology significantly but had no observable effect on vegetative development. These floral-specific mutant phenotypes and the restriction of PIM gene expression to flowers contrast with other known floral meristem genes in pea that additionally affect vegetative development. The identification of PIM provides an opportunity to compare pathways to flowering in species with different inflorescence architectures. PMID:12114569
Full Text Available In angiosperms, the production of flowers marks the beginning of the reproductive phase. At the emergence of flower primordia on the flanks of the inflorescence meristem, the WUSCHEL (WUS gene, which encodes a homeodomain transcription factor starts to be expressed and establishes de novo stem cell population, founder of the floral meristem (FM. Similarly to the shoot apical meristem a precise spatial and temporal expression pattern of WUS is required and maintained through strict regulation by multiple regulatory inputs to maintain stem cell homeostasis. However, following the formation of a genetically determined fixed number of floral organs, this homeostasis is shifted towards organogenesis and the FM is terminated. In here we performed a genetic study to test how a reduction in ERECTA, CLAVATA and class III HD-ZIP pathways affects floral meristem activity and flower development. We revealed strong synergistic phenotypes of extra flower number, supernumerary whorls, total loss of determinacy and extreme enlargement of the meristem as compared to any double mutant combination indicating that the three pathways, CLV3, ER and HD-ZIPIII distinctively regulate meristem activity and that they act in parallel. Our findings yield several new insights into stem cell-driven development. We demonstrate the crucial requirement for coupling floral meristem termination with carpel formation to ensure successful reproduction in plants. We also show how regulation of meristem size and alternation in spatial structure of the meristem serve as a mechanism to determine flower organogenesis. We propose that the loss of FM determinacy due to the reduction in CLV3, ER and HD-ZIPIII activity is genetically separable from the AGAMOUS core mechanism of meristem termination.
Chae, Eunyoung; Tan, Queenie K-G; Hill, Theresa A; Irish, Vivian F
Plants flower in response to both environmental and endogenous signals. The Arabidopsis LEAFY (LFY) transcription factor is crucial in integrating these signals, and acts in part by activating the expression of multiple floral homeotic genes. LFY-dependent activation of the homeotic APETALA3 (AP3) gene requires the activity of UNUSUAL FLORAL ORGANS (UFO), an F-box component of an SCF ubiquitin ligase, yet how this regulation is effected has remained unclear. Here, we show that UFO physically interacts with LFY both in vitro and in vivo, and this interaction is necessary to recruit UFO to the AP3 promoter. Furthermore, a transcriptional repressor domain fused to UFO reduces endogenous LFY activity in plants, supporting the idea that UFO acts as part of a transcriptional complex at the AP3 promoter. Moreover, chemical or genetic disruption of proteasome activity compromises LFY-dependent AP3 activation, indicating that protein degradation is required to promote LFY activity. These results define an unexpected role for an F-box protein in functioning as a DNA-associated transcriptional co-factor in regulating floral homeotic gene expression. These results suggest a novel mechanism for promoting flower development via protein degradation and concomitant activation of the LFY transcription factor. This mechanism may be widely conserved, as homologs of UFO and LFY have been identified in a wide array of plant species.
Nandi, A K; Kushalappa, K; Prasad, K; Vijayraghavan, U
Studies of floral organ development in two dicotyledonous plants, Arabidopsis thaliana and Antirrhinum majus, have shown that three sets of genes (A, B and C) can pattern sepals, petals, stamens and carpels  . Mechanisms that define boundaries between these floral whorls are unclear, however. The Arabidopsis gene SUPERMAN (SUP), which encodes a putative transcription factor, maintains the boundary between stamens and carpels   , possibly by regulating cell proliferation. By overexpressing SUP cDNA in rice, we examined whether its effects on whorl boundaries are conserved in a divergent monocotyledonous species. High-level ectopic SUP expression in transgenic rice resulted in juvenile death or dwarf plants with decreased axillary growth. Plants with lower levels of SUP RNA were vegetatively normal, but the flowers showed ubiquitous ventral carpel expansion. This was often coupled with reduced stamen number, or occurrence of third-whorl stamen-carpel mosaic organs. Additionally, proliferation of second-whorl ventral cells produced adventitious lodicules, and flowers lost the asymmetry that is normally inherent to this whorl. We predict that SUP is a conserved regulator of floral whorl boundaries and that it affects cell proliferation.
Full Text Available Pak choi (Brassica rapa ssp. chinensis Makino is a representative seed vernalization vegetable and premature bolting in spring can cause significant economic loss. Thus, it is critical to elucidate the mechanism of molecular regulation of vernalization and floral bud initiation to prevent premature bolting. Gibberellin (GA is the key plant hormone involved in regulating plant development. To gain a better understanding of GA metabolism in pak choi, the content of GA in pak choi was measured at different stages of plant development using enzyme-linked immunosorbent assay. The results showed that the GA content increased significantly after low-temperature treatment (4°C and then decreased rapidly with vegetative growth. During floral bud initiation, the GA content increased rapidly until it peaked upon floral bud differentiation. To elucidate these changes in GA content, the expression of homologous genes encoding enzymes directly involved in GA metabolism were analyzed. The results showed that the changes in the expression of four genes involved in GA synthesis (Bra035120 encoding ent-kaurene synthase, Bra009868 encoding ent-kaurene oxidase, Bra015394 encoding ent-kaurenoic acid oxidase, and Bra013890 encoding GA20-oxidase were correlated with the changes in GA content. In addition, by comparing the expression of genes involved in GA metabolism at different growth stages, seven differentially expressed genes (Bra005596, Bra009285, Bra022565, Bra008362, Bra033324, Bra010802, and Bra030500 were identified. The differential expression of these genes were directly correlated with changes in GA content, suggesting that these genes were directly related to vernalization, floral bud initiation and development. These results contribute to the understanding of the molecular mechanism of changes in GA content during different developmental phases in pak choi.
He, Reqing; Li, Xinmei; Zhong, Ming; Yan, Jindong; Ji, Ronghuan; Li, Xu; Wang, Qin; Wu, Dan; Sun, Mengsi; Tang, Dongying; Lin, Jianzhong; Li, Hongyu; Liu, Bin; Liu, Hongtao; Liu, Xuanming; Zhao, Xiaoying; Lin, Chentao
Floral initiation is regulated by various genetic pathways in response to light, temperature, hormones and developmental status; however, the molecular mechanisms underlying the interactions between different genetic pathways are not fully understood. Here, we show that the photoresponsive gene FOF2 (F-box of flowering 2) negatively regulates flowering. FOF2 encodes a putative F-box protein that interacts specifically with ASK14, and its overexpression results in later flowering under both long-day and short-day photoperiods. Conversely, transgenic plants expressing the F-box domain deletion mutant of FOF2 (FOF2ΔF), or double loss of function mutant of FOF2 and FOL1 (FOF2-LIKE 1) present early flowering phenotypes. The late flowering phenotype of the FOF2 overexpression lines is suppressed by the flc-3 loss-of-function mutation. Furthermore, FOF2 mRNA expression is regulated by autonomous pathway gene FCA, and the repressive effect of FOF2 in flowering can be overcome by vernalization. Interestingly, FOF2 expression is regulated by light. The protein level of FOF2 accumulates in response to light, whereas it is degraded under dark conditions via the 26S proteasome pathway. Our findings suggest a possible mechanistic link between light conditions and the autonomous floral promotion pathway in Arabidopsis. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.
Leeggangers, Hendrika A C F; Nijveen, Harm; Bigas, Judit Nadal; Hilhorst, Henk W M; Immink, Richard G H
The vegetative-to-reproductive phase change in tulip ( Tulipa gesneriana ) is promoted by increasing temperatures during spring. The warm winters of recent years interfere with this process and are calling for new adapted cultivars. A better understanding of the underlying molecular mechanisms would be of help, but unlike the model plant Arabidopsis ( Arabidopsis thaliana ), very little is known about floral induction in tulip. To shed light on the gene regulatory network controlling flowering in tulip, RNA sequencing was performed on meristem-enriched tissue collected under two contrasting temperature conditions, low and high. The start of reproductive development correlated with rounding of the shoot apical meristem and induction of TGSQA expression, a tulip gene with a high similarity to Arabidopsis APETALA1 Gene Ontology enrichment analysis of differentially expressed genes showed the overrepresentation of genes potentially involved in floral induction, bulb maturation, and dormancy establishment. Expression analysis revealed that TERMINAL FLOWER1 ( TgTFL1 ) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1-like1 ( TgSOC1-like1 ) might be repressors, whereas TgSOC1-like2 likely is an activator, of flowering. Subsequently, the flowering time-associated expression of eight potential flowering time genes was confirmed in three tulip cultivars grown in the field. Additionally, heterologous functional analyses in Arabidopsis resulted in flowering time phenotypes in line with TgTFL1 being a floral repressor and TgSOC1-like2 being a floral activator in tulip. Taken together, we have shown that long before morphological changes occur in the shoot apical meristem, the expression of floral repressors in tulip is suppressed by increased ambient temperatures, leading either directly or indirectly to the activation of potential flowering activators shortly before the commencement of the phase change. © 2017 American Society of Plant Biologists. All Rights Reserved.
Wu, Di, E-mail: DiWu@mail.nankai.edu.cn; Wu, Shian
Highlights: •Ser-17 is key for the stability of Drosophila Sav. •Ala mutation of Ser-17 promotes the proteasomal degradation of Sav. •Ser-17 residue is not the main target of Hpo-induced Sav stabilization. •Hpo-dependent and -independent mechanisms regulate Sav stability. •This mechanism is conserved in the homologue of Sav, human WW45. -- Abstract: The Hippo (Hpo) pathway is a conserved tumor suppressor pathway that controls organ size through the coordinated regulation of apoptosis and proliferation. Drosophila Salvador (Sav), which limits organ size, is a core component of the Hpo pathway. In this study, Ser-17 was shown to be important for the stability of Sav. Alanine mutation of Ser-17 promoted the proteasomal degradation of Sav. Destabilization and stabilization of the Sav protein mediated by alanine mutation of Ser-17 and by Hpo, respectively, were independent of each other. This implies that the stability of Sav is controlled by two mechanisms, one that is Ser-17-dependent and Hpo-independent, and another that is Ser-17-independent and Hpo-dependent. These dual mechanisms also regulated the human counterpart of Drosophila Sav, WW domain-containing adaptor 45 (WW45). The conservation of this regulation adds to its significance in normal physiology and tumorigenesis.
Full Text Available The Tsc1–Tsc2 complex homologous to human tuberous sclerosis complex proteins governs amino acid uptake by regulating the expression and intracellular distribution of amino acid transporters in Schizosaccharomyces pombe. Here, we performed a genetic screening for molecules that are involved in amino acid uptake and found Arn1 (also known as Any1. Arn1 is homologous to ART1, an arrestin-related trafficking adaptor (ART in Saccharomyces cerevisiae, and contains a conserved arrestin motif, a ubiquitination site, and two PY motifs. Overexpression of arn1+ confers canavanine resistance on cells, whereas its disruption causes hypersensitivity to canavanine. We also show that Arn1 regulates endocytosis of the Cat1 amino acid transporter. Furthermore, deletion of arn1+ suppresses a defect of amino acid uptake and the aberrant Cat1 localization in tsc2Δ. Arn1 interacts with and is ubiquitinated by the Pub1 ubiquitin ligase, which is necessary to regulate Cat1 endocytosis. Cat1 undergoes ubiquitinations on lysine residues within the N-terminus, which are mediated, in part, by Arn1 to determine Cat1 localization. Correctively, Arn1 is an ART in S. pombe and contributes to amino acid uptake through regulating Cat1 endocytosis in which Tsc2 is involved.
Zhao, D; Yang, M; Solava, J; Ma, H
Normal flower development likely requires both specific and general regulators. We have isolated an Arabidopsis mutant ask1-1 (for -Arabidopsis skp1-like1-1), which exhibits defects in both vegetative and reproductive development. In the ask1-1mutant, rosette leaf growth is reduced, resulting in smaller than normal rosette leaves, and internodes in the floral stem are shorter than normal. Examination of cell sizes in these organs indicates that cell expansion is normal in the mutant, but cell number is reduced. In the mutant, the numbers of petals and stamens are reduced, and many flowers have one or more petals with a reduced size. In addition, all mutant flowers have short stamen filaments. Furthermore, petal/stamen chimeric organs are found in many flowers. These results indicate that the ASK1 gene affects the size of vegetative and floral organs. The ask1 floral phenotype resembles somewhat that of the Arabidopsis ufo mutants in that both genes affect whorls 2 and 3. We therefore tested for possible interactions between ASK1 and UFO by analyzing the phenotypes of ufo-2 ask1-1 double mutant plants. In these plants, vegetative development is similar to that of the ask1-1 single mutant, whereas the floral defects are more severe than those in either single mutant. Interior to the first whorl, the double mutant flowers have more sepals or sepal-like organs than are found in ufo-2, and less petals than ask1-1. Our results suggest that ASK1 interacts with UFO to control floral organ identity in whorls 2 and 3. This is very intriguing because ASK1 is very similar in sequence to the yeast SKP1 protein and UFO contains an F-box, a motif known to interact with SKP1 in yeast. Although the precise mechanism of ASK1 and UFO action is unknown, our results support the hypothesis that these two proteins physically interact in vivo. Copyright 1999 Wiley-Liss, Inc.
Full Text Available Rai/ShcC is a member of the Shc family of protein adaptors expressed with the highest abundance in the central nervous system, where it exerts a protective function by coupling neurotrophic receptors to the PI3K/Akt survival pathway. Rai is also expressed, albeit at lower levels, in other cell types, including T and B lymphocytes. We have previously reported that in these cells Rai attenuates antigen receptor signaling, thereby impairing not only cell proliferation but also, opposite to neurons, cell survival. Here we have addressed the mechanism underlying the inhibitory activity of Rai on TCR signaling. We show that Rai interferes with the TCR signaling cascade one of the earliest steps--recruitment of the initiating kinase ZAP-70 to the phosphorylated subunit of the TCR/CD3 complex, which results in a generalized dampening of the downstream signaling events. The inhibitory activity of Rai is associated to its inducible recruitment to phosphorylated CD3, which occurs in the physiological signaling context of the immune synapse. Rai is moreover found as a pre-assembled complex with ZAP-70 and also constitutively interacts with the regulatory p85 subunit of PI3K, similar to neuronal cells, notwithstanding the opposite biological outcome, i.e. impairment of PI-3K/Akt activation. The data highlight the ability of Rai to establish interactions with the TCR and key signaling mediators which, either directly (e.g. by inhibiting ZAP-70 recruitment to the TCR or sequestering ZAP-70/PI3K in the cytosol or indirectly (e.g. by promoting the recruitment of effectors responsible for signal extinction prevent full triggering of the TCR signaling cascade.
Proust, Richard; Bertoglio, Jacques; Gesbert, Franck
Mutations altering the gene encoding the SLAM associated protein (SAP) are responsible for the X-linked lymphoproliferative disease or XLP1. Its absence is correlated with a defective NKT cells development, a decrease in B cell functions and a reduced T cells and NK cells cytotoxic activities, thus leading to an immunodeficiency syndrome. SAP is a small 128 amino-acid long protein that is almost exclusively composed of an SH2 domain. It has been shown to interact with the CD150/SLAM family of receptors, and in a non-canonical manner with SH3 containing proteins such as Fyn, βPIX, PKCθ and Nck1. It would thus play the role of a minimal adaptor protein. It has been shown that SAP plays an important function in the activation of T cells through its interaction with the SLAM family of receptors. Therefore SAP defective T cells display a reduced activation of signaling events downstream of the TCR-CD3 complex triggering. In the present work, we evidence that SAP is a direct interactor of the CD3ζ chain. This direct interaction occurs through the first ITAM of CD3ζ, proximal to the membrane. Additionally, we show that, in the context of the TCR-CD3 signaling, an Sh-RNA mediated silencing of SAP is responsible for a decrease of several canonical T cell signaling pathways including Erk, Akt and PLCγ1 and to a reduced induction of IL-2 and IL-4 mRNA. Altogether, we show that SAP plays a central function in the T cell activation processes through a direct association with the CD3 complex. PMID:22912825
Zhang, Jinjin; Yan, Guohua; Wen, Zhifeng; An, Young-Qiang; Singer, Stacy D; Liu, Zongrang
The genetic engineering of agronomic traits requires an array of highly specific and tightly regulated promoters that drive expression in floral tissues. In this study, we isolated and characterized two tobacco APETALA1-like (AP1-like) promoters (termed NtAP1La and NtAP1Lb1) in transgenic plants using the GUS reporter system, along with tissue-specific ablation analyses. Our results demonstrated that the two promoters are active in floral inflorescences but not in vegetative apical meristems or other vegetative tissues, as reflected by strong GUS staining and DT-A-mediated ablation of apical shoot tips during reproductive but not vegetative growth. We also showed that the NtAP1Lb1 promoter was more active than NtAP1La in inflorescences, as the former yielded higher frequencies and greater phenotypic evidence of tissue ablation compared to the latter. We further revealed that both promoters were uniformly expressed in the meristems of stage 1 and 2 floral buds, but were differentially expressed in floral organs later during development. While NtAP1La was found to be active in stage 4-5 carpels, later becoming confined to ovary tissue from stage 9 onwards, NtAP1Lb1 activity was apparent in all floral organs from stages 3 to 7, becoming completely absent in all floral organs from stage 11 onward. Therefore, it seems that the two tobacco promoters have acquired similar but distinct inflorescence-, floral meristem- and floral organ-specific and development-dependent regulatory features without any leaky activity in vegetative tissues. These features are novel and have rarely been observed in other flower-specific promoters characterized to date. The potential application of these promoters for engineering sterility, increasing biomass production and modifying flower architecture, as well as their putative use in flower-specific transgene excision, will be discussed.
Proust, Richard; Crouin, Catherine; Gandji, Leslie Yewakon; Bertoglio, Jacques; Gesbert, Franck
SAP is a small cytosolic adaptor protein expressed in hematopoietic lineages whose main function is to regulate intracellular signaling pathways induced by the triggering of members of the SLAM receptor family. In this paper, we have identified the adhesion molecule PECAM-1 as a new partner for SAP in a conditional yeast two-hybrid screen. PECAM-1 is an immunoglobulin-like molecule expressed by endothelial cells and leukocytes, which possesses both pro- and anti-inflammatory properties. However, little is known about PECAM-1 functions in T cells. We show that SAP directly and specifically interacts with the cytosolic tyrosine 686 of PECAM-1. We generated different T-like cell lines in which SAP or PECAM-1 are expressed or down modulated and we demonstrate that a diminished SAP expression correlates with a diminished PECAM-1-mediated adhesion. Although SAP has mainly been shown to associate with SLAM receptors, we evidence here that SAP is a new actor downstream of PECAM-1. Copyright © 2013 Elsevier Ltd. All rights reserved.
Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya; Cardell, Susanna L.; Stein, Paul L.; Wang, Chyung-Ru
CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule-associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT cell TCR transgenic mouse model (24αβTg), we demonstrated that CD1d-expressing hematopoietic cells but not thymic epithelial cells meditate efficient selection of type II NKT cells. Further, we showed that SAP regulates type II NKT cell development by controlling Egr2 and PLZF expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IRF4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP. PMID:25236978
Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya; Cardell, Susanna L; Stein, Paul L; Wang, Chyung-Ru
CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT-cell TCR transgenic mouse model, we demonstrated that CD1d-expressing hematopoietic cells, but not thymic epithelial cells, meditate efficient selection of type II NKT cells. Furthermore, we showed that SAP regulates type II NKT-cell development by controlling early growth response 2 protein and promyelocytic leukemia zinc finger expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IFN regulatory factor 4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Full Text Available Sleep is homeostatically regulated, such that sleep drive reflects the duration of prior wakefulness. However, despite the discovery of genes important for sleep, a coherent molecular model for sleep homeostasis has yet to emerge. To better understand the function and regulation of sleep, we employed a reverse-genetics approach in Drosophila. An insertion in the BTB domain protein CG32810/insomniac (inc exhibited one of the strongest baseline sleep phenotypes thus far observed, a ~10 h sleep reduction. Importantly, this is coupled to a reduced homeostatic response to sleep deprivation, consistent with a disrupted sleep homeostat. Knockdown of the INC-interacting protein, the E3 ubiquitin ligase Cul3, results in reduced sleep duration, consolidation, and homeostasis, suggesting an important role for protein turnover in mediating INC effects. Interestingly, inc and Cul3 expression in post-mitotic neurons during development contributes to their adult sleep functions. Similar to flies with increased dopaminergic signaling, loss of inc and Cul3 result in hyper-arousability to a mechanical stimulus in adult flies. Furthermore, the inc sleep duration phenotype can be rescued by pharmacological inhibition of tyrosine hydroxylase, the rate-limiting enzyme for dopamine biosynthesis. Taken together, these results establish inc and Cul3 as important new players in setting the sleep homeostat and a dopaminergic arousal pathway in Drosophila.
Debbie L Cunningham
Full Text Available Eps8 is involved in both cell signalling and receptor trafficking. It is a known phosphorylation substrate for two proteins involved in the fibroblast growth factor receptor (FGFR signalling pathway: the receptor itself and Src. Here we report a differential proteomic analysis of Eps8 aimed to identify specific FGFR and Src family kinase dependent phosphosites and co-associated phosphodependent binding partners. This study reveals a total of 22 Eps8 pTyr and pSer/Thr phosphorylation sites, including those that are dependent on Src family and FGFR kinase activity. Peptide affinity purification of proteins that bind to a selection of the pTyr phosphosites has identified a range of novel Eps8 binding partners including members of the intracellular vesicle trafficking machinery (clathrin and AP-2, proteins which have been shown to regulate activated receptor trafficking (NBR1 and Vav2, and proteins involved in receptor signalling (IRS4 and Shp2. Collectively this study significantly extends the understanding of Eps8 post-translational modification by regulated phosphorylation, identifies novel Eps8 binding partners implicated in receptor trafficking and signalling, and confirms the functions of Eps8 at the nexus of receptor signalling and vesicular trafficking.
Li, Chaoqiong; Fu, Qiantang; Niu, Longjian; Luo, Li; Chen, Jianghua; Xu, Zeng-Fu
Recent research revealed that TERMINAL FLOWER 1 (TFL1) homologues are involved in the critical developmental process of floral initiation in several plant species. In this study, the functions of three putative TFL1 homologues (JcTFL1a, JcTFL1b and JcTFL1c) in the biofuel plant Jatropha curcas were analysed using the transgenic approach. JcTFL1b and JcTFL1c, but not JcTFL1a, could complement the TFL1 function and rescue early flowering and determinate inflorescence phenotype in tfl1-14 Arabidopsis mutant, thus suggesting that JcTFL1b and JcTFL1c may be homologues of TFL1. Transgenic Jatropha overexpressing JcTFL1a, JcTFL1b or JcTFL1c showed late flowering, whereas only JcTFL1b and JcTFL1c overexpression delayed flowering in transgenic Arabidopsis. JcTFL1b-RNAi transgenic Jatropha consistently exhibited moderately early flowering phenotype. JcFT and JcAP1 were significantly downregulated in transgenic Jatropha overexpressing JcTFL1a, JcTFL1b or JcTFL1c, which suggested that the late flowering phenotype of these transgenic Jatropha may result from the repressed expression of JcFT and JcAP1. Our results indicate that these three JcTFL1 genes play redundant roles in repressing flowering in Jatropha. PMID:28225036
Butenko, Melinka A; Shi, Chun-Lin; Aalen, Reidunn B
Cell separation processes, such as abscission, are critical for plant development and play key roles from sculpting the form of the plant to scattering seeds. It is however essential that such processes are under tight temporal and spatial regulation. Floral organ abscission in Arabidopsis thaliana is regulated by a ligand-receptor module consisting of the signaling peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) and the two receptor-like kinases HAESA (HAE) and HAESA-LIKE 2 (HSL2), and it is the restricted expression pattern of IDA that hinders cell separation from occurring in the abscission zones (AZs) of other organs where HAE and HSL2 are present. In the July issue of The Plant Cell we report on the identification of additional components acting downstream in the IDA signaling pathway. Through a screen for mutations that restore floral organ abscission in ida mutants, we identified two new alleles of the KNOTTED-LIKE HOMEOBOX gene BREVIPEDICELLUS (BP)/KNOTTED-LIKE FROM ARABIDOPSIS THALIANA1 (KNAT1) and show that BP/KNAT1 is important in regulating the timing of floral abscission by controlling AZ cell size and by regulating KNAT2 and KNAT6.
Kusters, E.; Della Pina, S.; Castel, R.; Souer, E.; Koes, R.
Higher plant species diverged extensively with regard to the moment (flowering time) and position (inflorescence architecture) at which flowers are formed. This seems largely caused by variation in the expression patterns of conserved genes that specify floral meristem identity (FMI), rather than
Kusters, E.; Della Pina, S.; Castel, R.; Souer, E.J.; Koes, R.E.
Higher plant species diverged extensively with regard to the moment (flowering time) and position (inflorescence architecture) at which flowers are formed. This seems largely caused by variation in the expression patterns of conserved genes that specify floral meristem identity (FMI), rather than
Kaufmann, Kerstin; Wellmer, Frank; Muiño, Jose M; Ferrier, Thilia; Wuest, Samuel E; Kumar, Vijaya; Serrano-Mislata, Antonio; Madueño, Francisco; Krajewski, Pawel; Meyerowitz, Elliot M; Angenent, Gerco C; Riechmann, José Luis
The MADS-domain transcription factor APETALA1 (AP1) is a key regulator of Arabidopsis flower development. To understand the molecular mechanisms underlying AP1 function, we identified its target genes during floral initiation using a combination of gene expression profiling and genome-wide binding studies. Many of its targets encode transcriptional regulators, including known floral repressors. The latter genes are down-regulated by AP1, suggesting that it initiates floral development by abrogating the inhibitory effects of these genes. Although AP1 acts predominantly as a transcriptional repressor during the earliest stages of flower development, at more advanced stages it also activates regulatory genes required for floral organ formation, indicating a dynamic mode of action. Our results further imply that AP1 orchestrates floral initiation by integrating growth, patterning, and hormonal pathways.
Huang, Zong-An; Zhao, Ting; Wang, Ning; Zheng, Shu-Song
Anthocyanins are the conspicuous pigments of flowering plants and participate in several aspects of plant development and defense, such as seeds and pollens dispersal. Leaf colour (Lc) is the first basic/helix-loop-helix (bHLH) transcription factor controlling anthocyanin biosynthesis isolated from maize (Zea mays L.). Ectopic expression of maize Lc enhanced anthocyanin biosynthesis in many plants including tobacco (Nicotiana tobacum L.). However, the molecular regulatory mechanism of anthocyanin biosynthesis in the different floral parts of tobacco remains largely unknown. Therefore, the molecular and biochemical characterization of anthocyanin biosynthesis were investigated in the flowers of both wild type and Lc-transgenic tobacco plants. At the reproductive stage, with respect to the different parts of the flowers in wild type SR1, the calyxes and the pistils were green, and the petals and the filaments showed light pink pigmentation; the Lc-transgenic tobacco exhibited light red in calyxes and crimson in petals and in filaments respectively. Correspondingly, the total anthocyanin contents (TAC) in calyxes, petals and filaments of Lc-transgenic plants were much higher than that of the counterparts in SR1. Though the TAC in anthers of Lc-transgenic plants was low, it was still significantly higher than that of SR1. SR1 has almost the same TAC in the pistils as Lc-transgenic plants. Consistent with the intense phenotype and the increased TAC, Lc was weakly expressed in the calyxes and strongly expressed in petals and filaments of Lc-transgenic plants, while Lc was not detected in SR1. The expression level of NtAN2 in petals was similar between SR1 and Lc-transgenic lines. In agreement with the expression profile of Lc, both early (NtCHS) and late anthocyanin-biosynthetic genes (NtDFR, NtF3'H, and NtANS) were coordinately up-regulated in the counterparts of flowers. HPLC analysis demonstrated that the cyanidin (Cya) deposition was mainly responsible for the
Regulador vegetal e bioestimulante na indução floral do maracujazeiro-amarelo em condições de entressafra Plant regulator and biostimulant in yellow passion-fruit floral induction under non inductive condition
Elma Machado Ataíde
Full Text Available O objetivo do trabalho foi avaliar o efeito de regulador vegetal e de bioestimulante na indução floral do maracujazeiro-amarelo em condições não-indutivas, em Araguari-MG. Foram identificados e podados 12 ramos terciários por parcela (02-04-05, sendo 6 deles expostos de um lado da espaldeira, com luminosidade predominante pela manhã e 6 do outro lado da espaldeira, com luminosidade à tarde. O delineamento experimental foi em parcelas subdivididas, com 7 tratamentos principais (parcelas: 0mg L-1 (testemunha; 100mg L-1; 200mg L-1 e 300mg L-1 de regulador vegetal GA3 (i.a.; 2,08 mL L-1; 4,17mL L-1 e 6,25mL L-1 de bioestimulante Stimulate® (i.a., em duas aplicações foliares (09-04-02 e 09-05-02, acrescidas de espalhante adesivo Silwett® a 0,05%. Além desses, foram utilizados 2 tratamentos secundários (subparcelas: exposição dos ramos à luminosidade da manhã e da tarde, com 4 repetições de 3 plantas por parcela. Cada subparcela foi um dos dois lados da espaldeira. As médias foram comparadas pelo teste de Tukey, a 5% de probabilidade. Realizou-se, aos 75 dias, a avaliação nos dois lados da espaldeira do comprimento dos ramos e entrenós, número de nós, de folhas e de botões florais. As variáveis estudadas não foram influenciadas pelo uso de GA3 e Stimulate®, no entanto houve diferença quando os ramos ficaram expostos à luminosidade da manhã em relação àqueles com luminosidade à tarde.The objective of the present work was to evaluate the effect of plant regulator and biostimulant in the floral induction of yellow passion-fruit under non inductive conditions in Araguari-MG. Twelve tertiary branches were identified and trimmed per plot (04/02/04, whereas six were exposed, on one side of the supporting stick, with predominant luminosity during the morning and six on the other side of the supporting stick, with luminosity during the evening. The experimental design was subdivided plots, with main treatments (plots: 0mg L
Al-Eryani, Yusra; Ib Rasmussen, Morten; Kjellström, Sven
Adaptor proteins assist proteases in degrading specific proteins under appropriate conditions. The adaptor protein YjbH promotes the degradation of an important global transcriptional regulator Spx, which controls the expression of hundreds of genes and operons in response to thiol-specific oxida...
Hu, Ming-Ming; Yang, Qing; Xie, Xue-Qin; Liao, Chen-Yang; Lin, Heng; Liu, Tian-Tian; Yin, Lei; Shu, Hong-Bing
During viral infection, sensing of cytosolic DNA by the cyclic GMP-AMP synthase (cGAS) activates the adaptor protein STING and triggers an antiviral response. Little is known about the mechanisms that determine the kinetics of activation and deactivation of the cGAS-STING pathway, ensuring effective but controlled innate antiviral responses. Here we found that the ubiquitin ligase Trim38 targets cGas for sumoylation in uninfected cells and during the early phase of viral infection. Sumoylation of cGas prevented its polyubiquitination and degradation. Trim38 also sumoylated Sting during the early phase of viral infection, promoting both Sting activation and protein stability. In the late phase of infection, cGas and Sting were desumoylated by Senp2 and subsequently degraded via proteasomal and chaperone-mediated autophagy pathways, respectively. Our findings reveal an essential role for Trim38 in the innate immune response to DNA virus and provide insight into the mechanisms that ensure optimal activation and deactivation of the cGAS-STING pathway. Copyright © 2016 Elsevier Inc. All rights reserved.
Pol, van de P.A.
1972-01-01The factors, influencing the synthesis and action of floral hormones, and possible differences between floral hormones in different plants were studied. The experimental results are summarized in the conclusions 1-20, on pages 35-36 (Crassulaceae'); 21-39 on pages
Liang, Shan; Ye, Qing-Sheng; Li, Rui-Hong; Leng, Jia-Yi; Li, Mei-Ru; Wang, Xiao-Jing; Li, Hong-Qing
Vernalization-induced flowering is a cold-relevant adaptation in many species, but little is known about the genetic basis behind in Orchidaceae species. Here, we reported a collection of 15017 expressed sequence tags (ESTs) from the vernalized axillary buds of an Orchidaceae species, Dendrobium nobile, which were assembled for 9616 unique gene clusters. Functional enrichment analysis showed that genes in relation to the responses to stresses, especially in the form of low temperatures, and those involving in protein biosynthesis and chromatin assembly were significantly overrepresented during 40 days of vernalization. Additionally, a total of 59 putative flowering-relevant genes were recognized, including those homologous to known key players in vernalization pathways in temperate cereals or Arabidopsis, such as cereal VRN1, FT/VRN3, and Arabidopsis AGL19. Results from this study suggest that the networks regulating vernalization-induced floral transition are conserved, but just in a part, in D. nobile, temperate cereals, and Arabidopsis.
Full Text Available Vernalization-induced flowering is a cold-relevant adaptation in many species, but little is known about the genetic basis behind in Orchidaceae species. Here, we reported a collection of 15017 expressed sequence tags (ESTs from the vernalized axillary buds of an Orchidaceae species, Dendrobium nobile, which were assembled for 9616 unique gene clusters. Functional enrichment analysis showed that genes in relation to the responses to stresses, especially in the form of low temperatures, and those involving in protein biosynthesis and chromatin assembly were significantly overrepresented during 40 days of vernalization. Additionally, a total of 59 putative flowering-relevant genes were recognized, including those homologous to known key players in vernalization pathways in temperate cereals or Arabidopsis, such as cereal VRN1, FT/VRN3, and Arabidopsis AGL19. Results from this study suggest that the networks regulating vernalization-induced floral transition are conserved, but just in a part, in D. nobile, temperate cereals, and Arabidopsis.
Characterization of Toll-like receptors in primary lung epithelial cells: strong impact of the TLR3 ligand poly(I:C on the regulation of Toll-like receptors, adaptor proteins and inflammatory response
Full Text Available Abstract Background Bacterial and viral exacerbations play a crucial role in a variety of lung diseases including COPD or asthma. Since the lung epithelium is a major source of various inflammatory mediators that affect the immune response, we analyzed the inflammatory reaction of primary lung epithelial cells to different microbial molecules that are recognized by Toll-like receptors (TLR. Methods The effects of TLR ligands on primary small airway epithelial cells were analyzed in detail with respect to cytokine, chemokine and matrix metalloproteinase secretion. In addition, the regulation of the expression of TLRs and their adaptor proteins in small airway epithelial cells was investigated. Results Our data demonstrate that poly(I:C, a synthetic analog of viral dsRNA, mediated the strongest proinflammatory effects among the tested ligands, including an increased secretion of IL-6, IL-8, TNF-α, GM-CSF, GRO-α, TARC, MCP-1, MIP-3α, RANTES, IFN-β, IP-10 and ITAC as well as an increased release of MMP-1, MMP-8, MMP-9, MMP-10 and MMP-13. Furthermore, our data show that poly(I:C as well as type-1 and type-2 cytokines have a pronounced effect on the expression of TLRs and molecules involved in TLR signaling in small airway epithelial cells. Poly(I:C induced an elevated expression of TLR1, TLR2 and TLR3 and increased the gene expression of the general TLR adaptor MyD88 and IRAK-2. Simultaneously, poly(I:C decreased the expression of TLR5, TLR6 and TOLLIP. Conclusion Poly(I:C, an analog of viral dsRNA and a TLR3 ligand, triggers a strong inflammatory response in small airway epithelial cells that is likely to contribute to viral exacerbations of pulmonary diseases like asthma or COPD. The pronounced effects of poly(I:C on the expression of Toll-like receptors and molecules involved in TLR signaling is assumed to influence the immune response of the lung epithelium to viral and bacterial infections. Likewise, the regulation of TLR expression by type
Stepanek, Ondrej; Draber, Peter; Horejsi, Vaclav
Transmembrane adaptor proteins (TRAPs) are structurally related proteins that have no enzymatic function, but enable inducible recruitment of effector molecules to the plasma membrane, usually in a phosphorylation dependent manner. Numerous surface receptors employ TRAPs for either propagation or negative regulation of the signal transduction. Several TRAPs (LAT, NTAL, PAG, LIME, PRR7, SCIMP, LST1/A, and putatively GAPT) are known to be palmitoylated that could facilitate their localization in lipid rafts or tetraspanin enriched microdomains. This review summarizes expression patterns, binding partners, signaling pathways, and biological functions of particular palmitoylated TRAPs with an emphasis on the three most recently discovered members, PRR7, SCIMP, and LST1/A. Moreover, we discuss in silico methodology used for discovery of new family members, nature of their binding partners, and microdomain localization. Copyright © 2014 Elsevier Inc. All rights reserved.
Yasui, Yukiko; Tanaka, Wakana; Sakamoto, Tomoaki; Kurata, Tetsuya; Hirano, Hiro-Yuki
Meristems such as the shoot apical meristem and flower meristem (FM) act as a reservoir of stem cells, which reproduce themselves and supply daughter cells for the differentiation of lateral organs. In Oryza sativa (rice), the FLORAL ORGAN NUMBER2 (FON2) gene, which is similar to Arabidopsis CLAVATA3, is involved in meristem maintenance. In fon2 mutants, the numbers of floral organs are increased due to an enlargement of the FM. To identify new factors regulating meristem maintenance in rice, we performed a genetic screening of mutants that enhanced the fon2 mutation, and found a mutant line (2B-424) in which pistil number was dramatically increased. By using a map-based approach and next-generation sequencing, we found that the line 2B-424 had a complete loss-of-function mutation (a large deletion) in OsMADS3, a class C MADS-box gene that is known to be involved in stamen specification. Disruption of OsMADS3 in the fon2 mutant by CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9) technology caused a flower phenotype similar to that of 2B-424, confirming that the gene responsible for enhancement of fon2 was OsMADS3. Morphological analysis showed that the fon2 and osmads3 mutations synergistically affected pistil development and FM determinacy. We also found that whorl 3 was duplicated in mature flowers and the FM was enlarged at an early developmental stage in severe osmads3 single mutants. These findings suggest that OsMADS3 is involved not only in FM determinacy in late flower development but also in FM activity in early flower development. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: firstname.lastname@example.org.
Full Text Available Adaptor protein (AP complexes sort cargo into vesicles for transport from one membrane compartment of the cell to another. Four distinct AP complexes have been identified, which are present in most eukaryotes. We report the existence of a fifth AP complex, AP-5. Tagged AP-5 localises to a late endosomal compartment in HeLa cells. AP-5 does not associate with clathrin and is insensitive to brefeldin A. Knocking down AP-5 subunits interferes with the trafficking of the cation-independent mannose 6-phosphate receptor and causes the cell to form swollen endosomal structures with emanating tubules. AP-5 subunits can be found in all five eukaryotic supergroups, but they have been co-ordinately lost in many organisms. Concatenated phylogenetic analysis provides robust resolution, for the first time, into the evolutionary order of emergence of the adaptor subunit families, showing AP-3 as the basal complex, followed by AP-5, AP-4, and AP-1 and AP-2. Thus, AP-5 is an evolutionarily ancient complex, which is involved in endosomal sorting, and which has links with hereditary spastic paraplegia.
In der vorliegenden Arbeit wurde erstmalig die vollständige cDNA-Sequenz des Proteinkinase A-Ankerproteins-2 (AKAP-2, 7,5kB) ermittelt. Zu diesem neuen humanen Gen sind bis dato außer einem unvollständigem Datenbankeintrag noch keine experimentellen Daten zur cDNA, mRNA oder zum Protein veröffentlicht. Mittels Northernblot wurde die Regulation der Expression der mRNA von AKAP-2 in humanem osteoblastären hFOB-Zellen sowie ihre Expression in unterschiedlichen Geweben untersucht: In hFOB-Zellen ...
Greenup, Aaron G.; Sasani, Shahryar; Oliver, Sandra N.; Talbot, Mark J.; Dennis, Elizabeth S.; Hemming, Megan N.; Trevaskis, Ben
In temperate cereals, such as wheat (Triticum aestivum) and barley (Hordeum vulgare), the transition to reproductive development can be accelerated by prolonged exposure to cold (vernalization). We examined the role of the grass-specific MADS box gene ODDSOC2 (OS2) in the vernalization response in cereals. The barley OS2 gene (HvOS2) is expressed in leaves and shoot apices but is repressed by vernalization. Vernalization represses OS2 independently of VERNALIZATION1 (VRN1) in a VRN1 deletion mutant of einkorn wheat (Triticum monococcum), but VRN1 is required to maintain down-regulation of OS2 in vernalized plants. Furthermore, barleys that carry active alleles of the VRN1 gene (HvVRN1) have reduced expression of HvOS2, suggesting that HvVRN1 down-regulates HvOS2 during development. Overexpression of HvOS2 delayed flowering and reduced spike, stem, and leaf length in transgenic barley plants. Plants overexpressing HvOS2 showed reduced expression of barley homologs of the Arabidopsis (Arabidopsis thaliana) gene FLOWERING PROMOTING FACTOR1 (FPF1) and increased expression of RNase-S-like genes. FPF1 promotes floral development and enhances cell elongation, so down-regulation of FPF1-like genes might explain the phenotypes of HvOS2 overexpression lines. We present an extended model of the genetic pathways controlling vernalization-induced flowering in cereals, which describes the regulatory relationships between VRN1, OS2, and FPF1-like genes. Overall, these findings highlight differences and similarities between the vernalization responses of temperate cereals and the model plant Arabidopsis. PMID:20431086
Izaguirre, Miriam M; Mazza, Carlos A; Astigueta, María S; Ciarla, Ana M; Ballaré, Carlos L
Plant fitness is often defined by the combined effects of herbivory and competition, and plants must strike a delicate balance between their ability to capture limiting resources and defend against herbivore attack. Many plants use indirect defenses, such as volatile compounds and extra floral nectaries (EFN), to attract canopy arthropods that are natural enemies of herbivorous organisms. While recent evidence suggests that upon perception of low red to far-red (R:FR) ratios, which signal the proximity of competitors, plants down-regulate resource allocation to direct chemical defenses, it is unknown if a similar phytochrome-mediated response occurs for indirect defenses. We evaluated the interactive effects of R:FR ratio and simulated herbivory on nectar production by EFNs of passion fruit (Passiflora edulis f. flavicarpa). The activity of petiolar EFNs dramatically increased in response to simulated herbivory and hormonal treatment with methyl jasmonate (MeJA). Low R:FR ratios, which induced a classic "shade-avoidance" repertoire of increased stem elongation in P. edulis, strongly suppressed the EFN response triggered by simulated herbivory or MeJA application. Strikingly, the EFN response to wounding and light quality was localized to the branches that received the treatments. In vines like P. edulis, a local response would allow the plants to precisely adjust their light harvesting and defense phenotypes to the local conditions encountered by individual branches when foraging for resources in patchy canopies. Consistent with the emerging paradigm that phytochrome regulation of jasmonate signaling is a central modulator of adaptive phenotypic plasticity, our results demonstrate that light quality is a strong regulator of indirect defenses.
Full Text Available BACKGROUND: PDZK1 is a four PDZ-domain containing cytoplasmic protein that binds to a variety of membrane proteins via their C-termini and can influence the abundance, localization and/or function of its target proteins. One of these targets in hepatocytes in vivo is the HDL receptor SR-BI. Normal hepatic expression of SR-BI protein requires PDZK1 - <5% of normal hepatic SR-BI is seen in the livers of PDZK1 knockout mice. Progress has been made in identifying features of PDZK1 required to control hepatic SR-BI in vivo using hepatic expression of wild-type and mutant forms of PDZK1 in wild-type and PDZK1 KO transgenic mice. Such in vivo studies are time consuming and expensive, and cannot readily be used to explore many features of the underlying molecular and cellular mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Here we have explored the potential to use either primary rodent hepatocytes in culture using 2D collagen gels with newly developed optimized conditions or PDZK1/SR-BI co-transfected cultured cell lines (COS, HEK293 for such studies. SR-BI and PDZK1 protein and mRNA expression levels fell rapidly in primary hepatocyte cultures, indicating this system does not adequately mimic hepatocytes in vivo for analysis of the PDZK1 dependence of SR-BI. Although PDZK1 did alter SR-BI protein expression in the cell lines, its influence was independent of SR-BI's C-terminus, and thus is not likely to occur via the same mechanism as that which occurs in hepatocytes in vivo. CONCLUSIONS/SIGNIFICANCE: Caution must be exercised in using primary hepatocytes or cultured cell lines when studying the mechanism underlying the regulation of hepatic SR-BI by PDZK1. It may be possible to use SR-BI and PDZK1 expression as sensitive markers for the in vivo-like state of hepatocytes to further improve primary hepatocyte cell culture conditions.
Lohmann, J. U., and Weigel, D.
OAK-B135 Floral organ identity is controlled by combinatorial action of homeotic genes expressed in different territories within the emerging flower. This review discusses recent progress in our understanding of floral homeotic genes, with an emphasis on how their region-specific expression is regulated.
Wellmer, Frank; Graciet, Emmanuelle; Riechmann, José Luis
Floral organs are specified by the activities of a small group of transcriptional regulators, the floral organ identity factors. Extensive genetic and molecular analyses have shown that these proteins act as master regulators of flower development, and function not only in organ identity determination but also during organ morphogenesis. Although it is now well established that these transcription factors act in higher order protein complexes in the regulation of transcription, the gene expression programmes controlled by them have remained largely elusive. Only recently, detailed insights into their functions have been obtained through the combination of a wide range of experimental methods, including transcriptomic and proteomic approaches. Here, we review the progress that has been made in the characterization of the floral organ identity factors from the main model plant Arabidopsis thaliana, and we discuss what is known about the processes acting downstream of these regulators. We further outline open questions, which we believe need to be addressed to obtain a more complete view of the molecular processes that govern floral organ development and specification.
Kaufmann, K.; Wellmer, F.; Muino, J.M.; Ferrier, T.; Wuest, S.E.; Kumar, V.; Serrano-Mislata, A.; Madueno, F.; Krajweski, P.; Meyerowitz, E.M.; Angenent, G.C.; Riechmann, J.L.
The MADS-domain transcription factor APETALA1 (AP1) is a key regulator of Arabidopsis flower development. To understand the molecular mechanisms underlying AP1 function, we identified its target genes during floral initiation using a combination of gene expression profiling and genome-wide binding
Davis, Charles C; Endress, Peter K; Baum, David A
Flowers exhibit tremendous variation in size (>1000-fold), ranging from less than a millimeter to nearly a meter in diameter. Numerous studies have established the importance of increased floral size in species that exhibit relatively normal-sized flowers, but few studies have examined the evolution of floral size increase in species with extremely large flowers or flower-like inflorescences (collectively termed blossoms). Our review of these record-breakers indicates that blossom gigantism has evolved multiple times, and suggests that the evolutionary forces operating in these species may differ from their ordinary-sized counterparts. Surprisingly, rather than being associated with large-bodied pollinators, gigantism appears to be most common in species with small-bodied beetle or carrion-fly pollinators. Such large blossoms may be adapted to these pollinators because they help to temporarily trap animals, better facilitate thermal regulation, and allow for the mimicry of large animal carcasses. Future phylogenetic tests of these hypotheses should be conducted to determine if the transition to such pollination systems correlates with significant changes in the mode and tempo of blossom size evolution.
Peñuelas, Josep; Farré-Armengol, Gerard; Llusia, Joan; Gargallo-Garriga, Albert; Rico, Laura; Sardans, Jordi; Terradas, Jaume; Filella, Iolanda
The emission of floral terpenes plays a key role in pollination in many plant species. We hypothesized that the floral phyllospheric microbiota could significantly influence these floral terpene emissions because microorganisms also produce and emit terpenes. We tested this hypothesis by analyzing the effect of removing the microbiota from flowers. We fumigated Sambucus nigra L. plants, including their flowers, with a combination of three broad-spectrum antibiotics and measured the floral emissions and tissular concentrations in both antibiotic-fumigated and non-fumigated plants. Floral terpene emissions decreased by ca. two thirds after fumigation. The concentration of terpenes in floral tissues did not decrease, and floral respiration rates did not change, indicating an absence of damage to the floral tissues. The suppression of the phyllospheric microbial communities also changed the composition and proportion of terpenes in the volatile blend. One week after fumigation, the flowers were not emitting β-ocimene, linalool, epoxylinalool, and linalool oxide. These results show a key role of the floral phyllospheric microbiota in the quantity and quality of floral terpene emissions and therefore a possible key role in pollination.
Ee, Jessie; Seng, Tan Oon; Kwang, Ng Aik
Kirton (1976) described two creative styles, namely adaptors and innovators. Adaptors prefer to "do things better" whilst, innovators prefer to "do things differently". This study explored the relationship between two creative styles (adaptor and innovator) and the Big Five personality traits (extraversion, agreeableness, conscientiousness,…
Noman, Ali; Aqeel, Muhammad; Deng, Jianming; Khalid, Noreen; Sanaullah, Tayyaba; Shuilin, He
Developing new ornamental cultivars with improved floral attributes is a major goal in floriculture. Biotechnological approach together with classical breeding methods has been used to modify floral color, appearance as well as for increasing disease resistance. Transgenic strategies possess immense potential to produce novel flower phenotypes that are not found in nature. Adoption of Genetic engineering has supported the idea of floral trait modification. Ornamental plant attributes like floral color, fragrance, disease resistance, and vase life can be improved by means of genetic manipulation. Therefore, we witness transgenic plant varieties of high aesthetic and commercial value. This review focuses on biotechnological advancements in manipulating key floral traits that contribute in development of diverse ornamental plant lines. Data clearly reveals that regulation of biosynthetic pathways related to characteristics like pigment production, flower morphology and fragrance is both possible and predictable. In spite of their great significance, small number of genetically engineered varieties of ornamental plants has been field tested. Today, novel flower colors production is regarded as chief commercial benefit obtained from transgenic plants. But certain other floral traits are much more important and have high commercial potential. Other than achievements such as novel architecture, modified flower color, etc., very few reports are available regarding successful transformation of other valuable horticultural characteristics. Our review also summarized biotechnological efforts related to enhancement of fragrance and induction of early flowering along with changes in floral anatomy and morphology.
Full Text Available Developing new ornamental cultivars with improved floral attributes is a major goal in floriculture. Biotechnological approach together with classical breeding methods has been used to modify floral color, appearance as well as for increasing disease resistance. Transgenic strategies possess immense potential to produce novel flower phenotypes that are not found in nature. Adoption of Genetic engineering has supported the idea of floral trait modification. Ornamental plant attributes like floral color, fragrance, disease resistance, and vase life can be improved by means of genetic manipulation. Therefore, we witness transgenic plant varieties of high aesthetic and commercial value. This review focuses on biotechnological advancements in manipulating key floral traits that contribute in development of diverse ornamental plant lines. Data clearly reveals that regulation of biosynthetic pathways related to characteristics like pigment production, flower morphology and fragrance is both possible and predictable. In spite of their great significance, small number of genetically engineered varieties of ornamental plants has been field tested. Today, novel flower colors production is regarded as chief commercial benefit obtained from transgenic plants. But certain other floral traits are much more important and have high commercial potential. Other than achievements such as novel architecture, modified flower color, etc., very few reports are available regarding successful transformation of other valuable horticultural characteristics. Our review also summarized biotechnological efforts related to enhancement of fragrance and induction of early flowering along with changes in floral anatomy and morphology.
Full Text Available To successfully recruit pollinators, plants often release attractive floral scents at specific times of day to coincide with pollinator foraging. This timing of scent emission is thought to be evolutionarily beneficial to maximize resource efficiency while attracting only useful pollinators. Temporal regulation of scent emission is tied to the activity of the specific metabolic pathways responsible for scent production. Although floral volatile profiling in various plants indicated a contribution by the circadian clock, the mechanisms by which the circadian clock regulates timing of floral scent emission remained elusive. Recent studies using two species in the Solanaceae family provided initial insight into molecular clock regulation of scent emission timing. In Petunia hybrida, the benzenoid/phenylpropanoid (FVBP pathway is the major metabolic pathway that produces floral volatiles. Three MYB-type transcription factors, ODORANT1 (ODO1, EMISSION OF BENZENOIDS I (EOBI, and EOBII, all of which show diurnal rhythms in mRNA expression, act as positive regulators for several enzyme genes in the FVBP pathway. Recently, in P. hybrida and Nicotiana attenuata, homologs of the Arabidopsis clock gene LATE ELONGATED HYPOCOTYL (LHY have been shown to have a similar role in the circadian clock in these plants, and to also determine the timing of scent emission. In addition, in P. hybrida, PhLHY directly represses ODO1 and several enzyme genes in the FVBP pathway during the morning as an important negative regulator of scent emission. These findings facilitate our understanding of the relationship between a molecular timekeeper and the timing of scent emission, which may influence reproductive success.
Bożena Denisow; Monika Strzałkowska-Abramek; Anna Jeżak
Floral reward is important in ecological and evolutionary perspectives and essential in pollination biology. For example, floral traits, nectar and pollen features are essential for understanding the functional ecology, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. We believe to present a synthetic description in the field of floral reward in Ranunculaceae family important in pollinati...
Full Text Available Many adaptor proteins involved in endocytic cargo transport exhibit additional functions in other cellular processes which may be either related to or independent from their trafficking roles. The endosomal adaptor protein Tollip is an example of such a multitasking regulator, as it participates in trafficking and endosomal sorting of receptors, but also in interleukin/Toll/NF-κB signaling, bacterial entry, autophagic clearance of protein aggregates and regulation of sumoylation. Here we describe another role of Tollip in intracellular signaling. By performing a targeted RNAi screen of soluble endocytic proteins for their additional functions in canonical Wnt signaling, we identified Tollip as a potential negative regulator of this pathway in human cells. Depletion of Tollip potentiates the activity of β-catenin/TCF-dependent transcriptional reporter, while its overproduction inhibits the reporter activity and expression of Wnt target genes. These effects are independent of dynamin-mediated endocytosis, but require the ubiquitin-binding CUE domain of Tollip. In Wnt-stimulated cells, Tollip counteracts the activation of β-catenin and its nuclear accumulation, without affecting its total levels. Additionally, under conditions of ligand-independent signaling, Tollip inhibits the pathway after the stage of β-catenin stabilization, as observed in human cancer cell lines, characterized by constitutive β-catenin activity. Finally, the regulation of Wnt signaling by Tollip occurs also during early embryonic development of zebrafish. In summary, our data identify a novel function of Tollip in regulating the canonical Wnt pathway which is evolutionarily conserved between fish and humans. Tollip-mediated inhibition of Wnt signaling may contribute not only to embryonic development, but also to carcinogenesis. Mechanistically, Tollip can potentially coordinate multiple cellular pathways of trafficking and signaling, possibly by exploiting its ability to
Full Text Available Floral organogenesis requires coordinated interactions between genes specifying floral organ identity and those regulating growth and size of developing floral organs. With the aim to isolate regulatory genes linking both developmental processes (i.e. floral organ identity and growth in the tomato model species, a novel mutant altered in the formation of floral organs was further characterized. Under normal growth conditions, floral organ primordia of mutant plants were correctly initiated, however, they were unable to complete their development impeding the formation of mature and fertile flowers. Thus, the growth of floral buds was blocked at an early stage of development; therefore, we named this mutant as unfinished flower development (ufd. Genetic analysis performed in a segregating population of 543 plants showed that the abnormal phenotype was controlled by a single recessive mutation. Global gene expression analysis confirmed that several MADS-box genes regulating floral identity as well as other genes participating in cell division and different hormonal pathways were affected in their expression patterns in ufd mutant plants. Moreover, ufd mutant inflorescences showed higher hormone contents, particularly ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC and strigol compared to wild type. Such results indicate that UFD may have a key function as positive regulator of the development of floral primordia once they have been initiated in the four floral whorls. This function should be performed by affecting the expression of floral organ identity and growth genes, together with hormonal signalling pathways.
Rae Eden Yumul
Full Text Available Termination of the stem cells in the floral meristem (also known as floral determinacy is critical for the reproductive success of plants, and the molecular activities regulating floral determinacy are precisely orchestrated during the course of floral development. In Arabidopsis thaliana, regulators of floral determinacy include several transcription factor genes, such as APETALA2 (AP2, AGAMOUS (AG, SUPERMAN (SUP, and CRABSCLAW (CRC, as well as a microRNA (miRNA, miR172, which targets AP2. How the transcription factor and miRNA genes are coordinately regulated to achieve floral determinacy is unknown. A mutation in POWERDRESS (PWR, a previously uncharacterized gene encoding a SANT-domain-containing protein, was isolated in this study as an enhancer of the weakly indeterminate ag-10 allele. PWR was found to promote the transcription of CRC, MIR172a, b, and c and/or enhance Pol II occupancy at their promoters, without affecting MIR172d or e. A mutation in mature miR172d was additionally found to enhance the determinacy defects of ag-10 in an AP2-dependent manner, providing direct evidence that miR172d is functional in repressing AP2 and thereby contributes to floral determinacy. Thus, while PWR promotes floral determinacy by enhancing the expression of three of the five MIR172 members as well as CRC, MIR172d, whose expression is PWR-independent, also functions in floral stem cell termination. Taken together, these findings demonstrate how transcriptional diversification and functional redundancy of a miRNA family along with PWR-mediated co-regulation of miRNA and transcription factor genes contribute to the robustness of the floral determinacy network.
Chanderbali, André S; Albert, Victor A; Leebens-Mack, Jim; Altman, Naomi S; Soltis, Douglas E; Soltis, Pamela S
The debate on the origin and evolution of flowers has recently entered the field of developmental genetics, with focus on the design of the ancestral floral regulatory program. Flowers can differ dramatically among angiosperm lineages, but in general, male and female reproductive organs surrounded by a sterile perianth of sepals and petals constitute the basic floral structure. However, the basal angiosperm lineages exhibit spectacular diversity in the number, arrangement, and structure of floral organs, whereas the evolutionarily derived monocot and eudicot lineages share a far more uniform floral ground plan. Here we show that broadly overlapping transcriptional programs characterize the floral transcriptome of the basal angiosperm Persea americana (avocado), whereas floral gene expression domains are considerably more organ specific in the model eudicot Arabidopsis thaliana. Our findings therefore support the "fading borders" model for organ identity determination in basal angiosperm flowers and extend it from the action of regulatory genes to downstream transcriptional programs. Furthermore, the declining expression of components of the staminal transcriptome in central and peripheral regions of Persea flowers concurs with elements of a previous hypothesis for developmental regulation in a gymnosperm "floral progenitor." Accordingly, in contrast to the canalized organ-specific regulatory apparatus of Arabidopsis, floral development may have been originally regulated by overlapping transcriptional cascades with fading gradients of influence from focal to bordering organs.
Endress, Peter K; Armstrong, Joseph E
Background and Aims Anaxagorea is the phylogenetically basalmost genus in the large tropical Annonaceae (custard apple family) of Magnoliales, but its floral structure is unknown in many respects. The aim of this study is to analyse evolutionarily interesting floral features in comparison with other genera of the Annonaceae and the sister family Eupomatiaceae. Methods Live flowers of Anaxagorea crassipetala were examined in the field with vital staining, liquid-fixed material was studied with scanning electron microscopy, and microtome section series were studied with light microscopy. In addition, herbarium material of two other Anaxagorea species was cursorily studied with the dissecting microscope. Key Results Floral phyllotaxis in Anaxagorea is regularly whorled (with complex whorls) as in all other Annonaceae with a low or medium number of floral organs studied so far (in those with numerous stamens and carpels, phyllotaxis becoming irregular in the androecium and gynoecium). The carpels are completely plicate as in almost all other Annonaceae. In these features Anaxagorea differs sharply from the sister family Eupomatiaceae, which has spiral floral phyllotaxis and ascidiate carpels. Flat stamens and the presence of inner staminodes differ from most other Annonaceae and may be plesiomorphic in Anaxagorea. However, the inner staminodes appear to be non-secretory in most Anaxagorea species, which differs from inner staminodes in other families of Magnoliales (Eupomatiaceae, Degeneriacae, Himantandraceae), which are secretory. Conclusions Floral phyllotaxis in Anaxagorea shows that there is no signature of a basal spiral pattern in Annonaceae and that complex whorls are an apomorphy not just for a part of the family but for the family in its entirety, and irregular phyllotaxis is derived. This and the presence of completely plicate carpels in Anaxagorea makes the family homogeneous and distinguishes it from the closest relatives in Magnoliales.
Acosta M., Emma M.; Salud Pública. Facultad de Farmacia y Bioquímica de la Universidad Nacional Mayor de San Marcos, Lima, Perú.; Villarán, Jhon Eddowes; Facultad de Psicología. Universidad Garcilaso de la Vega.
The work is a style of research: "Research in Action," which is the small-scale intervention in the functioning of the real world and a clase examination of the effects of such intervention, the ultimate goal being to improve practice. How to improve the practice af floral therapy in our country? Have the input for the preparation of flower remedies and therefore at this stage I had to get 21 flower essences Peruvian natural resources, in order to access and availability of floral therapy. Wh...
Full Text Available As a step toward functional annotation of genes required for floral initiation and development within the Eucalyptus genome, we used short read sequencing to analyze transcriptomes of floral buds from early and late developmental stages...
Abbeyquaye, Tetteh; Riesgo-Escovar, Juan; Raabe, Thomas; Thackeray, Justin R
The Gab/dos/Soc-1 proteins form a family of multi-adaptor/scaffolding proteins involved in receptor tyrosine kinase signaling. To further understanding of the Gab family and the Drosophila Dos protein in particular, we isolated a dos homolog from both Drosophila pseudoobscura and Drosophila virilis and compared their gene structures and protein sequences with the rest of the Gab family. The presence of two conserved introns confirmed that the dos and gab genes are orthologous, but the Caenorhabditis elegans soc-1 gene had no unambiguously conserved introns with either dos or gab. However, phylogenetic analysis suggests that soc-1 probably represents a divergent member of the Gab family. Apart from the PH domain, which is well conserved in all Gab family members, the proteins show a low level of sequence conservation. Two tyrosines that probably bind to the Src Homology 2 (SH2) domains of a tyrosine phosphatase in all Gab family members are conserved at the C-terminal end; two other potential SH2-binding sites in Dos were also identified, as well as several proline rich sequences that might bind to SH3 or EVH1 domains in other proteins. A major partner for mammalian Gab is phospholipase C-gamma (PLC-gamma); genetic and biochemical tests for a PLC-gamma-SH3::Dos interaction were negative, indicating that if Drosophila PLC-gamma binds to Dos, it must do so indirectly or through an SH2-phosphotyrosine interaction.
Full Text Available PLIC, Protein Linking IAP (CD47 to Cytoskeleton, have long since been implicated in connecting the extracellular membrane to the intracellular cell cytoskeleton. This phenomenon is supposedly achieved by bridging a receptor protein CD47 to vimentin, an intermediate filament, which in turn regulates integrin dependent cell spreading. Since the discovery of these proteins, the molecular details of the above-mentioned interactions and the underlying complexes are yet to be characterized. Several independent studies have together emphasized PLIC/Ubiquilin’s role in the proteasomal degradation pathway. This seems to be in contrast to the purported initial discovery of PLIC as a cytoskeletal adaptor protein. In an effort to reconcile the different roles associated with the ubiquitous PLIC proteins, we tested the involvement of PLIC-2 both in the proteasomal degradation pathway and as a protein linking the cell cytoskeleton to the cytoplasmic tail of CD47. This was achieved thorough an in vitro investigation of their binding interface using a combination of biophysical techniques. Our results show that the two terminal domains of PLIC-2 interact weakly with each other, while the C-terminal UBA domain interacts strongly with ubiquitin. Interestingly, no perceptible interaction was observed for PLIC-2 with the cytoplasmic tail of CD47 questioning its role as a “PLIC” protein linking the cell membrane to the cytoskeleton.
Floral essences were discovered in the decade of the thirties by the English doctor, bacteriologist and homeopath Dr. Edward Bach. He described 38 remedies elaborated with flowers and shoots; each one correspondeds to an emotional pattern or a typical personality. Furthermore, he describes a remedy developed for emergency situations.
Al-Eryani, Yusra; Ib Rasmussen, Morten; Kjellström, Sven; Højrup, Peter; Emanuelsson, Cecilia; von Wachenfeldt, Claes
Adaptor proteins assist proteases in degrading specific proteins under appropriate conditions. The adaptor protein YjbH promotes the degradation of an important global transcriptional regulator Spx, which controls the expression of hundreds of genes and operons in response to thiol-specific oxidative stress in Bacillus subtilis. Under normal growth conditions, the transcription factor is bound to the adaptor protein and therefore degraded by the AAA+ protease ClpXP. If this binding is alleviated during stress, the transcription factor accumulates and turns on genes encoding stress-alleviating proteins. The adaptor protein YjbH is thus a key player involved in these interactions but its structure is unknown. To gain insight into its structure and interactions we have used chemical crosslinking mass spectrometry. Distance constraints obtained from the crosslinked monomer were used to select and validate a structure model of YjbH and then to probe its interactions with other proteins. The core structure of YjbH is reminiscent of DsbA family proteins. One lysine residue in YjbH (K177), located in one of the α-helices outside the thioredoxin fold, crosslinked to both Spx K99 and Spx K117, thereby suggesting one side of the YjbH for the interaction with Spx. Another lysine residue that crosslinked to Spx was YjbH K5, located in the long and presumably very flexible N-terminal arm of YjbH. Our crosslinking data lend support to a model proposed based on site-directed mutagenesis where the YjbH interaction with Spx can stabilize and present the C-terminal region of Spx for protease recognition and proteolysis. Proteins 2016; 84:1234-1245. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Hatani, Tomoko; Sada, Kiyonao
The adaptor protein 3BP2 (c-Abl Src homology 3 domain-binding protein-2, also referred to SH3BP2) is known to play a regulatory role in signaling from immunoreceptors. In mast cells, 3BP2 is rapidly tyrosine phosphorylated by the aggregation of the high affinity IgE receptor and the overexpression of its SH2 domain results in the dramatic suppression of IgE-mediated tyrosine phosphorylation of PLC-alpha, Ca2+ mobilization and degranulation. 3BP2 is a substrate of the protein-tyrosine kinase Syk, which phosphorylates it on Tyr174, Tyr183, and Tyr446 (in the mouse protein). Phosphorylation of Tyr183 promotes the activation of Rac1 through the interaction with the SH2 domain of Vav1. Phosphorylation of Tyr446 induces the binding to the SH2 domain of the upstream protein-tyrosine kinase Lyn and enhances its kinase activity. Thus, 3BP2 has a positive regulatory role in IgE-mediated mast cell activation. In lymphocytes, engagement of T cell or B cell receptors triggers tyrosine phosphorylation of 3BP2. Suppression of the 3BP2 expression by siRNA results in the inhibition of T cell or B cell receptor-mediated activation of NFAT. Genetic analyses reveal that 3BP2 is required for the proliferation of B cells and B cell receptor signaling. Point mutations of the 3BP2 gene cause the rare human inherited disorder cherubism, characterized by excessive bone resorption in the jaw bones. These mutations include substitution and deletion mutations of 3BP2. "Cherubism" mice exhibit increased myeloid cell responses to M-CSF and RANKL leading to the activation of osteoclasts. Further analysis could demonstrate that inhibition of 3BP2 might have therapeutic potential.
Oh, Youngjoo; Baldwin, Ian T; Galis, Ivan
Jasmonic acid is an important regulator of plant growth, development and defense. The jasmonate-ZIM domain (JAZ) proteins are key regulators in jasmonate signaling ubiquitously present in flowering plants but their functional annotation remains largely incomplete. Recently, we identified 12 putative JAZ proteins in native tobacco, Nicotiana attenuata, and initiated systematic functional characterization of these proteins by reverse genetic approaches. In this report, Nicotiana attenuata plants silenced in the expression of NaJAZd (irJAZd) by RNA interference were used to characterize NaJAZd function. Although NaJAZd transcripts were strongly and transiently up-regulated in the rosette leaves by simulated herbivory treatment, we did not observe strong defense-related phenotypes, such as altered herbivore performance or the constitutive accumulation of defense-related secondary metabolites in irJAZd plants compared to wild type plants, both in the glasshouse and the native habitat of Nicotiana attenuata in the Great Basin Desert, Utah, USA. Interestingly, irJAZd plants produced fewer seed capsules than did wild type plants as a result of increased flower abscission in later stages of flower development. The early- and mid-developmental stages of irJAZd flowers had reduced levels of jasmonic acid and jasmonoyl-L-isoleucine, while fully open flowers had normal levels, but these were impaired in NaMYB305 transcript accumulations. Previously, NaMYB305-silenced plants were shown to have strong flower abscission phenotypes and contained lower NECTARIN 1 transcript levels, phenotypes which are copied in irJAZd plants. We propose that the NaJAZd protein is required to counteract flower abscission, possibly by regulating jasmonic acid and jasmonoyl-L-isoleucine levels and/or expression of NaMYB305 gene in Nicotiana attenuata flowers. This novel insight into the function of JAZ proteins in flower and seed development highlights the diversity of functions played by jasmonates
Ashley Rae Smith
Full Text Available Natural floral organ degeneration or abortion results in unisexual or fully sterile flowers, while abiotic stresses lead to sterility after initiation of floral reproductive organs. Since normal flower development is essential for plant sexual reproduction and crop yield, it is imperative to have a better understanding of plant sterility under regular and stress conditions. Here, we review the functions of ABC genes together with their downstream genes in floral organ degeneration and the formation of unisexual flowers in Arabidopsis and several agriculturally significant cereal grains. We further explore the roles of hormones, including auxin, brassinosteroids, jasmonic acid, gibberellic acid, and ethylene, in floral organ formation and fertility. We show that alterations in genes affecting hormone biosynthesis, hormone transport and perception cause loss of stamens/carpels, abnormal floral organ development, poor pollen production, which consequently result in unisexual flowers and male/female sterility. Moreover, abiotic stresses, such as heat, cold, and drought, commonly affect floral organ development and fertility. Sterility is induced by abiotic stresses mostly in male floral organ development, particularly during meiosis, tapetum development, anthesis, dehiscence, and fertilization. A variety of genes including those involved in heat shock, hormone signaling, cold tolerance, metabolisms of starch and sucrose, meiosis, and tapetum development are essential for plants to maintain normal fertility under abiotic stress conditions. Further elucidation of cellular, biochemical and molecular mechanisms about regulation of fertility will improve yield and quality for many agriculturally valuable crops.
Full Text Available Floral reward is important in ecological and evolutionary perspectives and essential in pollination biology. For example, floral traits, nectar and pollen features are essential for understanding the functional ecology, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. We believe to present a synthetic description in the field of floral reward in Ranunculaceae family important in pollination biology and indicating connections between ecological and evolutionary approaches. The links between insect visitors’ behaviour and floral reward type and characteristics exist. Ranunculaceae is a family of aboot 1700 species (aboot 60 genera, distributed worldwide, however the most abundant representatives are in temperate and cool regions of the northern and southern hemispheres. The flowers are usually radially symmetric (zygomorphic and bisexual, but in Aconitum, Aquilegia are bilaterally symmetric (zygomorphic. Most Ranunculaceae flowers offer no nectar, only pollen (e.g., Ranunculus, Adonis vernalis, Thalictrum, but numerous species create trophic niches for different wild pollinators (e.g. Osmia, Megachile, Bombus, Andrena (Denisow et al. 2008. Pollen is a source of protein, vitamins, mineral salts, organic acids and hormones, but the nutritional value varies greatly between different plant species. The pollen production can differ significantly between Ranunculacea species. The mass of pollen produced in anthers differ due to variations in the number of developed anthers. For example, interspecies differences are considerable, 49 anthers are noted in Aquilegia vulgaris, 70 anthers in Ranunculus lanuginosus, 120 in Adonis vernalis. A significant intra-species differences’ in the number of anthers are also noted (e.g. 41 to 61 in Aquilegia vulgaris, 23-45 in Ranunculus cassubicus. Pollen production can be up to 62 kg per ha for Ranunculus acer
Yoo, Mi-Jeong; Chanderbali, André S; Altman, Naomi S; Soltis, Pamela S; Soltis, Douglas E
Current understanding of floral developmental genetics comes primarily from the core eudicot model Arabidopsis thaliana. Here, we explore the floral transcriptome of the basal angiosperm, Nuphar advena (water lily), for insights into the ancestral developmental program of flowers. We identify several thousand Nuphar genes with significantly upregulated floral expression, including homologs of the well-known ABCE floral regulators, deployed in broadly overlapping transcriptional programs across floral organ categories. Strong similarities in the expression profiles of different organ categories in Nuphar flowers are shared with the magnoliid Persea americana (avocado), in contrast to the largely organ-specific transcriptional cascades evident in Arabidopsis, supporting the inference that this is the ancestral condition in angiosperms. In contrast to most eudicots, floral organs are weakly differentiated in Nuphar and Persea, with staminodial intermediates between stamens and perianth in Nuphar, and between stamens and carpels in Persea. Consequently, the predominantly organ-specific transcriptional programs that characterize Arabidopsis flowers (and perhaps other eudicots) are derived, and correlate with a shift towards morphologically distinct floral organs, including differentiated sepals and petals, and a perianth distinct from stamens and carpels. Our findings suggest that the genetic regulation of more spatially discrete transcriptional programs underlies the evolution of floral morphology. © 2010 The Authors. The Plant Journal © 2010 Blackwell Publishing Ltd.
Vining, Kelly J; Romanel, Elisson; Jones, Rebecca C; Klocko, Amy; Alves-Ferreira, Marcio; Hefer, Charles A; Amarasinghe, Vindhya; Dharmawardhana, Palitha; Naithani, Sushma; Ranik, Martin; Wesley-Smith, James; Solomon, Luke; Jaiswal, Pankaj; Myburg, Alexander A; Strauss, Steven H
As a step toward functional annotation of genes required for floral initiation and development within the Eucalyptus genome, we used short read sequencing to analyze transcriptomes of floral buds from early and late developmental stages, and compared these with transcriptomes of diverse vegetative tissues, including leaves, roots, and stems. A subset of 4807 genes (13% of protein-coding genes) were differentially expressed between floral buds of either stage and vegetative tissues. A similar proportion of genes were differentially expressed among all tissues. A total of 479 genes were differentially expressed between early and late stages of floral development. Gene function enrichment identified 158 gene ontology classes that were overrepresented in floral tissues, including 'pollen development' and 'aromatic compound biosynthetic process'. At least 40 floral-dominant genes lacked functional annotations and thus may be novel floral transcripts. We analyzed several genes and gene families in depth, including 49 putative biomarkers of floral development, the MADS-box transcription factors, 'S-domain'-receptor-like kinases, and selected gene family members with phosphatidylethanolamine-binding protein domains. Expanded MADS-box gene subfamilies in Eucalyptus grandis included SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1), SEPALLATA (SEP) and SHORT VEGETATIVE PHASE (SVP) Arabidopsis thaliana homologs. These data provide a rich resource for functional and evolutionary analysis of genes controlling eucalypt floral development, and new tools for breeding and biotechnology. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass adaptor, stopcock, manifold... Devices § 870.4290 Cardiopulmonary bypass adaptor, stopcock, manifold, or fitting. (a) Identification. A cardiopulmonary bypass adaptor, stopcock, manifold, or fitting is a device used in cardiovascular diagnostic...
Levin, J Z; Meyerowitz, E M
We describe the role of the UNUSUAL FLORAL ORGANS (UFO) gene in Arabidopsis floral development based on a genetic and molecular characterization of the phenotypes of nine ufo alleles. UFO is required for the proper identity of the floral meristem and acts in three different aspects of the process that distinguishes flowers from shoots. UFO is involved in establishing the whorled pattern of floral organs, controlling the determinacy of the floral meristem, and activating the APETALA3 and PISTILLATA genes required for petal and stamen identity. In many respects, UFO acts in a manner similar to LEAFY, but the ufo mutant phenotype also suggests an additional role for UFO in defining boundaries within the floral primordia or controlling cell proliferation during floral organ growth. Finally, genetic interactions that prevent flower formation and lead to the generation of filamentous structures implicate UFO as a member of a new, large, and diverse class of genes in Arabidopsis necessary for flower formation.
Stewart, Darragh; Graciet, Emmanuelle; Wellmer, Frank
The genetic and molecular mechanisms that underlie the formation of angiosperm flowers have been studied extensively for nearly three decades. This work has led to detailed insights into the gene regulatory networks that control this vital developmental process in plants. Here, we review some of the key findings in the field of flower development and discuss open questions that must be addressed in order to obtain a more comprehensive understanding of flower formation. In particular, we focus on the specification of the different types of floral organs and on how the morphogenesis of these organs is controlled to give rise to mature flowers. Central to this process are the floral organ identity genes, which encode members of the family of MADS-domain transcription factors. We summarize what is currently known about the functions of these master regulators and discuss a working model for the molecular mechanism that may underlie their activities. © 2016 Federation of European Biochemical Societies.
Full Text Available Eps15 is an endocytic adaptor protein involved in clathrin and non-clathrin mediated endocytosis. In Caenorhabditis elegans and Drosophila melanogaster lack of Eps15 leads to defects in synaptic vesicle recycling and synapse formation. We generated Eps15-KO mice to investigate its function in mammals. Eps15-KO mice are born at the expected Mendelian ratio and are fertile. Using a large-scale phenotype screen covering more than 300 parameters correlated to human disease, we found that Eps15-KO mice did not show any sign of disease or neural deficits. Instead, altered blood parameters pointed to an immunological defect. By competitive bone marrow transplantation we demonstrated that Eps15-KO hematopoietic precursor cells were more efficient than the WT counterparts in repopulating B220⁺ bone marrow cells, CD19⁻ thymocytes and splenic marginal zone (MZ B cells. Eps15-KO mice showed a 2-fold increase in MZ B cell numbers when compared with controls. Using reverse bone marrow transplantation, we found that Eps15 regulates MZ B cell numbers in a cell autonomous manner. FACS analysis showed that although MZ B cells were increased in Eps15-KO mice, transitional and pre-MZ B cell numbers were unaffected. The increase in MZ B cell numbers in Eps15 KO mice was not dependent on altered BCR signaling or Notch activity. In conclusion, in mammals, the endocytic adaptor protein Eps15 is a regulator of B-cell lymphopoiesis.
Yant, Levi; Mathieu, Johannes; Dinh, Thanh Theresa; Ott, Felix; Lanz, Christa; Wollmann, Heike; Chen, Xuemei; Schmid, Markus
The Arabidopsis thaliana transcription factor APETALA2 (AP2) has numerous functions, including roles in seed development, stem cell maintenance, and specification of floral organ identity. To understand the relationship between these different roles, we mapped direct targets of AP2 on a genome-wide scale in two tissue types. We find that AP2 binds to thousands of loci in the developing flower, many of which exhibit AP2-dependent transcription. Opposing, logical effects are evident in AP2 binding to two microRNA genes that influence AP2 expression, with AP2 positively regulating miR156 and negatively regulating miR172, forming a complex direct feedback loop, which also included all but one of the AP2-like miR172 target clade members. We compare the genome-wide direct target repertoire of AP2 with that of SCHLAFMÜTZE, a closely related transcription factor that also represses the transition to flowering. We detect clear similarities and important differences in the direct target repertoires that are also tissue specific. Finally, using an inducible expression system, we demonstrate that AP2 has dual molecular roles. It functions as both a transcriptional activator and repressor, directly inducing the expression of the floral repressor AGAMOUS-LIKE15 and directly repressing the transcription of floral activators like SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1. PMID:20675573
Li, Zheng; Chen, Wei
A drift detector array, preferably a silicon drift detector (SDD) array, that uses a low current biasing adaptor is disclosed. The biasing adaptor is customizable for any desired geometry of the drift detector single cell with minimum drift time of carriers. The biasing adaptor has spiral shaped ion-implants that generate the desired voltage profile. The biasing adaptor can be processed on the same wafer as the drift detector array and only one biasing adaptor chip/side is needed for one drift detector array to generate the voltage profiles on the front side and back side of the detector array.
Ó'Maoiléidigh, Diarmuid S; Stewart, Darragh; Zheng, Beibei; Coupland, George; Wellmer, Frank
As originally proposed by Goethe in 1790, floral organs are derived from leaf-like structures. The conversion of leaves into different types of floral organ is mediated by floral homeotic proteins, which, as described by the ABCE model of flower development, act in a combinatorial manner. However, how these transcription factors bring about this transformation process is not well understood. We have previously shown that floral homeotic proteins are involved in suppressing the formation of branched trichomes, a hallmark of leaf development, on reproductive floral organs of Arabidopsis Here, we present evidence that the activities of the C function gene AGAMOUS ( AG ) and the related SHATTERPROOF1 / 2 genes are superimposed onto the regulatory network that controls the distribution of trichome formation in an age-dependent manner. We show that AG regulates cytokinin responses and genetically interacts with the organ polarity gene KANADI1 to suppress trichome initiation on gynoecia. Thus, our results show that parts of the genetic program for leaf development remain active during flower formation but have been partially rewired through the activities of the floral homeotic proteins. © 2018. Published by The Company of Biologists Ltd.
Jarillo, Jose A; Piñeiro, Manuel
Progress in understanding the molecular basis of flowering time control has revealed that floral repressors play a central role in modulating the floral transition and are essential to prevent the precocious onset of flowering. A number of cellular processes including chromatin remodeling, selective protein degradation, and transcriptional regulation mediated by transcription factors are involved in repressing the initiation of flowering. Floral repressors interact at different levels with floral inductive pathways and prevent the premature onset of flowering that could impact negatively on the reproductive success of plants. Despite recent advances, further studies will be needed to understand how the interactions between floral repressors and the regulatory networks involved in the control of flowering time have evolved in different species. Recent data suggest that a diversity of regulatory proteins act as central floral repressors in different plants, and even in those species where regulatory modules are conserved new elements that modulate the function of these pathways have been recruited to mediate specific adaptive responses. The development of genomic tools and predictive models that can integrate large datasets related to the flowering behavior of plant species will facilitate the characterization of the repressor mechanisms underlying flowering responses, a trait with implications in the yield of crop species. In a scenario of global climate change, an in depth understanding of these gene circuits will be essential for the development of crop varieties with improved yield. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Han, Yingying; Zhang, Cui; Yang, Haibian; Jiao, Yuling
In angiosperms, after the floral transition, the inflorescence meristem produces floral meristems (FMs). Determinate growth of FMs produces flowers of a particular size and form. This determinate growth requires specification of floral organs and termination of stem-cell divisions. Establishment of the FM and specification of outer whorl organs (sepals and petals) requires the floral homeotic gene APETALA1 (AP1). To determine FM identity, AP1 also prevents the formation of flowers in the axils of sepals. The mechanisms underlying AP1 function in the floral transition and in floral organ patterning have been studied extensively, but how AP1 terminates sepal axil stem-cell activities to suppress axillary secondary flower formation remains unclear. Here we show that AP1 regulates cytokinin levels by directly suppressing the cytokinin biosynthetic gene LONELY GUY1 and activating the cytokinin degradation gene CYTOKININ OXIDASE/DEHYDROGENASE3. Restoring the expression of these genes to wild-type levels in AP1-expressing cells or suppressing cytokinin signaling inhibits indeterminate inflorescence meristem activity caused by ap1 mutation. We conclude that suppression of cytokinin biosynthesis and activation of cytokinin degradation mediates AP1 function in establishing determinate FM. A deeper understanding of axil-lateral meristem activity provides crucial information for enhancing yield by engineering crops that produce more elaborated racemes.
Wills, Melanie K B; Jones, Nina
Shc (Src homology and collagen homology) proteins are considered prototypical signalling adaptors in mammalian cells. Consisting of four unique members, ShcA, B, C and D, and multiple splice isoforms, the family is represented in nearly every cell type in the body, where it engages in an array of fundamental processes to transduce environmental stimuli. Two decades of investigation have begun to illuminate the mechanisms of the flagship ShcA protein, whereas much remains to be learned about the newest discovery, ShcD. It is clear, however, that the distinctive modular architecture of Shc proteins, their promiscuous phosphotyrosine-based interactions with a multitude of membrane receptors, involvement in central cascades including MAPK (mitogen-activated protein kinase) and Akt, and unconventional contributions to oxidative stress and apoptosis all require intricate regulation, and underlie diverse physiological function. From early cardiovascular development and neuronal differentiation to lifespan determination and tumorigenesis, Shc adaptors have proven to be more ubiquitous, versatile and dynamic than their structures alone suggest.
Kühn, Julius; Wong, Leo E; Pirkuliyeva, Sona; Schulz, Kathrin; Schwiegk, Claudia; Fünfgeld, Kevser Gencalp; Keppler, Selina; Batista, Facundo D; Urlaub, Henning; Habeck, Michael; Becker, Stefan; Griesinger, Christian; Wienands, Jürgen
The adaptor molecule Cbl-interacting protein of 85 kD (CIN85) regulates signaling from a number of cell surface receptors, such as growth factor receptors and antigen receptors on lymphocytes. Because of its multidomain structure, CIN85 is thought to act as a classical adaptor protein that connects functionally distinct components of a given signaling pathway through diverse protein domains. However, we found that in B lymphocytes, CIN85 functions to oligomerize SLP-65, which is the central effector protein of the B cell receptor (BCR). Therefore, CIN85 trimerizes through a carboxyl-terminal, coiled-coil domain. The multiple Src homology 3 (SH3) domains of trimeric CIN85 molecules associated with multiple SLP-65 molecules, which recruited further CIN85 trimers, thereby perpetuating the oligomerization process. Formation of this oligomeric signaling complex in resting B cells rendered the cells poised for the efficient initiation of intracellular signaling upon BCR stimulation. Our data suggest that the functionality of signaling cascades does not rely solely on the qualitative linkage of their various components but requires a critical number of effectors to become concentrated in signaling complexes. Copyright © 2016, American Association for the Advancement of Science.
Riffell, Jeffrey A.; Alarcón, Ruben
Background Combinations of floral traits – which operate as attractive signals to pollinators – act on multiple sensory modalities. For Manduca sexta hawkmoths, how learning modifies foraging decisions in response to those traits remains untested, and the contribution of visual and olfactory floral displays on behavior remains unclear. Methodology/Principal Findings Using M. sexta and the floral traits of two important nectar resources in southwestern USA, Datura wrightii and Agave palmeri, we examined the relative importance of olfactory and visual signals. Natural visual and olfactory cues from D. wrightii and A. palmeri flowers permits testing the cues at their native intensities and composition – a contrast to many studies that have used artificial stimuli (essential oils, single odorants) that are less ecologically relevant. Results from a series of two-choice assays where the olfactory and visual floral displays were manipulated showed that naïve hawkmoths preferred flowers displaying both olfactory and visual cues. Furthermore, experiments using A. palmeri flowers – a species that is not very attractive to hawkmoths – showed that the visual and olfactory displays did not have synergistic effects. The combination of olfactory and visual display of D. wrightii, however – a flower that is highly attractive to naïve hawkmoths – did influence the time moths spent feeding from the flowers. The importance of the olfactory and visual signals were further demonstrated in learning experiments in which experienced moths, when exposed to uncoupled floral displays, ultimately chose flowers based on the previously experienced olfactory, and not visual, signals. These moths, however, had significantly longer decision times than moths exposed to coupled floral displays. Conclusions/Significance These results highlight the importance of specific sensory modalities for foraging hawkmoths while also suggesting that they learn the floral displays as
Chandler, J W; Werr, W
The biphasic floral transition in Arabidopsis thaliana involves many redundant intersecting regulatory networks. The related AP2 transcription factors DORNRÖSCHEN (DRN), DORNRÖSCHEN-LIKE (DRNL), and PUCHI individually execute well-characterized functions in diverse developmental contexts, including floral development. Here, we show that their combined loss of function leads to synergistic floral phenotypes, including reduced floral merosity in all whorls, which reflects redundant functions of all three genes in organ initiation rather than outgrowth. Additional loss of BLADE-ON-PETIOLE1 (BOP1) and BOP2 functions results in the complete conversion of floral meristems into secondary inflorescence shoots, demonstrating that all five genes define an essential regulatory network for establishing floral meristem identity, and we show that their functions converge to regulate LEAFY expression. Thus, despite their largely discrete spatiotemporal expression domains in the inflorescence meristem and early floral meristem, PUCHI, DRN, and DRNL interdependently contribute to cellular fate decisions. Auxin might represent one potential non-cell-autonomous mediator of their gene functions, because PUCHI, DRN, and DRNL all interact with auxin transport and biosynthesis pathways. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: email@example.com.
Full Text Available Transition from vegetative to floral buds is a critical physiological change during flower induction that determines fruit productivity. Small non-coding RNAs (sRNAs including microRNAs (miRNAs and small interfering RNAs (siRNAs are pivotal regulators of plant growth and development. Although the key role of sRNAs in flowering regulation has been well-described in Arabidopsis and some other annual plants, their relevance to vegetative-to-floral transition (hereafter, referred to floral transition in perennial woody trees remains under defined. Here, we performed Illumina sequencing of sRNA libraries prepared from vegetative and floral bud during flower induction of the apple trees. A large number of sRNAs exemplified by 33 previously annotated miRNAs and six novel members display significant differential expression (DE patterns. Notably, most of these DE-miRNAs in floral transition displayed opposite expression changes in reported phase transition in apple trees. Bioinformatics analysis suggests most of the DE-miRNAs targeted transcripts involved in SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL gene regulation, stress responses, and auxin and gibberellin (GA pathways, with further suggestion that there is an inherent link between physiological stress response and metabolism reprogramming during floral transition. We also observed significant changes in 24 nucleotide (nt sRNAs that are hallmarks for RNA-dependent DNA methylation (RdDM pathway, suggestive of the correlation between epigenetic modifications and the floral transition. The study not only provides new insight into our understanding of fundamental mechanism of poorly studied floral transition in apple and other woody plants, but also presents important sRNA resource for future in-depth research in the apple flowering physiology.
Renaud, G.; Stenzel, U.; Kelso, J.
The sequencing of libraries containing molecules shorter than the read length, such as in ancient or forensic applications, may result in the production of reads that include the adaptor, and in paired reads that overlap one another. Challenges for the processing of such reads are the accurate identification of the adaptor sequence and accurate reconstruction of the original sequence most likely to have given rise to the observed read(s). We introduce an algorithm that removes the adaptors an...
Full Text Available Flowering is one of the important defining features of angiosperms. The initiation of flower development and the formation of different floral organs are the results of the interplays among numerous genes. But until now, just fewer genes have been found linked with flower development. And the functions of lots of genes of Arabidopsis thaliana are still unknown. Although, the quartet model successfully simplified the ABCDE model to elaborate the molecular mechanism by introducing protein-protein interactions (PPIs. We still don't know much about several important aspects of flower development. So we need to discriminate even more genes involving in the flower development. In this study, we identified seven differentially modules through integrating the weighted gene co-expression network analysis (WGCNA and Support Vector Machine (SVM method to analyze co-expression network and PPIs using the public floral and non-floral expression profiles data of Arabidopsis thaliana. Gene set enrichment analysis was used for the functional annotation of the related genes, and some of the hub genes were identified in each module. The potential floral organ morphogenesis genes of two significant modules were integrated with PPI information in order to detail the inherent regulation mechanisms. Finally, the functions of the floral patterning genes were elucidated by combining the PPI and evolutionary information. It was indicated that the sub-networks or complexes, rather than the genes, were the regulation unit of flower development. We found that the most possible potential new genes underlining the floral pattern formation in A. thaliana were FY, CBL2, ZFN3 and AT1G77370; among them, FY, CBL2 acted as an upstream regulator of AP2; ZFN3 activated the flower primordial determining gene AP1 and AP2 by HY5/HYH gene via photo induction possibly. And AT1G77370 exhibited similar function in floral morphogenesis, same as ELF3. It possibly formed a complex between RFC3
Andersen, C.H.; Jensen, C.S.; Petersen, K.
A recent paper by Million Tadege et A shows that a SOC1-like gene from rice, OsSOC1, can complement the Arabidopsis soc1 mutant, and that ectopic expression of the Arabidopsis floral repressor FLC in rice delays flowering and up-regulation of OsSOC1 These findings, together with the identificatio...... of the wheat vernalization VRN1 locus as an AP1 homologue, suggest that related genetic switch systems control floral transition in dicots and monocots but that they are based on different MADS-box transcription factors....
Broeckhove, J.; Vanmechelen, K.
Object-oriented programming using C++ is increasingly being adopted in the development of scientific codes. A recurrent issue in this regard is the interaction of newly developed codes with existing legacy libraries written in C or Fortran. Often, one needs to pass raw function pointers to such libraries' procedures for callback purposes. This is problematic as it conflicts with one of the cornerstones of object-oriented programming: the association of functions and data through objects. Currently ad hoc approaches are used to deal with this issue, but these are error-prone and lack reusability. We present a generic adaptor that is able to wrap any callable C++ entity and provide a raw function pointer that is compatible with C or Fortran library routines. This allows for an object-oriented style of programming, while interfacing with legacy libraries in a straightforward manner. Catalogue identifier: AENU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence /licence.html No. of lines in distributed program, including test data, etc.: 76802 No. of bytes in distributed program, including test data, etc.: 915389 Distribution format: tar.gz Programming language: C++. Computer: All. Operating system: All. Classification: 6.5, 4.14. Nature of problem: Object-oriented programming using C++ is increasingly being adopted in the development of scientific codes. A recurrent issue in this regard is the interaction of newly developed codes with existing legacy libraries written in C or Fortran. Often, one needs to pass raw function pointers to such libraries' procedures for callback purposes. This is problematic as it conflicts with one of the cornerstones of object-oriented programming: the association of functions and data through objects. Currently ad hoc approaches are used to deal with this
Sakai, H; Medrano, L J; Meyerowitz, E M
The Arabidopsis gene SUPERMAN (SUP) is necessary for the proper spatial development of reproductive floral tissues. Recessive mutations cause extra stamens to form interior to the normal third whorl stamens, at the expense of fourth whorl carpel development. The mutant phenotype is associated with the ectopic expression of the B function genes, AP3 and PI, in the altered floral region, closer to the centre of the flower than in the wild type, and ap3 sup and pi sup double mutants exhibit a phenotype similar to ap3 and pi single mutants. These findings led to SUP being interpreted as an upstream negative regulator of the B function organ-identity genes, acting in the fourth whorl, to establish a boundary between stamen and carpel whorls. Here we show, using molecular cloning and analysis, that it is expressed in the third whorl and acts to maintain this boundary in developing flowers. The putative SUPERMAN protein contains one zinc-finger and a region resembling a basic leucine zipper motif, suggesting a function in transcriptional regulation.
Levin, J Z; Fletcher, J C; Chen, X; Meyerowitz, E M
In a screen to identify novel genes required for early Arabidopsis flower development, we isolated four independent mutations that enhance the Ufo phenotype toward the production of filamentous structures in place of flowers. The mutants fall into three complementation groups, which we have termed FUSED FLORAL ORGANS (FFO) loci. ffo mutants have specific defects in floral organ separation and/or positioning; thus, the FFO genes identify components of a boundary formation mechanism(s) acting between developing floral organ primordia. FFO1 and FFO3 have specific functions in cauline leaf/stem separation and in first- and third-whorl floral organ separation, with FFO3 likely acting to establish and FFO1 to maintain floral organ boundaries. FFO2 acts at early floral stages to regulate floral organ number and positioning and to control organ separation within and between whorls. Plants doubly mutant for two ffo alleles display additive phenotypes, indicating that the FFO genes may act in separate pathways. Plants doubly mutant for an ffo gene and for ufo, lfy, or clv3 reveal that the FFO genes play roles related to those of UFO and LFY in floral meristem initiation and that FFO2 and FFO3 may act to control cell proliferation late in inflorescence development.
Levin, J Z; Fletcher, J C; Chen, X; Meyerowitz, E M
In a screen to identify novel genes required for early Arabidopsis flower development, we isolated four independent mutations that enhance the Ufo phenotype toward the production of filamentous structures in place of flowers. The mutants fall into three complementation groups, which we have termed FUSED FLORAL ORGANS (FFO) loci. ffo mutants have specific defects in floral organ separation and/or positioning; thus, the FFO genes identify components of a boundary formation mechanism(s) acting between developing floral organ primordia. FFO1 and FFO3 have specific functions in cauline leaf/stem separation and in first- and third-whorl floral organ separation, with FFO3 likely acting to establish and FFO1 to maintain floral organ boundaries. FFO2 acts at early floral stages to regulate floral organ number and positioning and to control organ separation within and between whorls. Plants doubly mutant for two ffo alleles display additive phenotypes, indicating that the FFO genes may act in separate pathways. Plants doubly mutant for an ffo gene and for ufo, lfy, or clv3 reveal that the FFO genes play roles related to those of UFO and LFY in floral meristem initiation and that FFO2 and FFO3 may act to control cell proliferation late in inflorescence development. PMID:9611175
Caruso, Christina M; Parachnowitsch, Amy L
Plants emit a diverse array of volatile organic compounds that can function as cues to other plants. Plants can use volatiles emitted by neighbors to gain information about their environment, and respond by adjusting their phenotype. Less is known about whether the many different volatile signals that plants emit are all equally likely to function as cues to other plants. We review evidence for the function of floral volatile signals and conclude that plants are as likely to perceive and respond to floral volatiles as to other, better-studied volatiles. We propose that eavesdropping on floral volatile cues is particularly likely to be adaptive because plants can respond to these cues by adjusting traits that directly affect pollination and mating. Copyright © 2015 Elsevier Ltd. All rights reserved.
Wilde H Dayton
Full Text Available Abstract Background Mutation scanning technology has been used to develop crop species with improved traits. Modifications that improve screening throughput and sensitivity would facilitate the targeted mutation breeding of crops. Technical innovations for high-resolution melting (HRM analysis are enabling the clinic-based screening for human disease gene polymorphism. We examined the application of two HRM modifications, COLD-PCR and QMC-PCR, to the mutation scanning of genes in peach, Prunus persica. The targeted genes were the putative floral regulators PpAGAMOUS and PpTERMINAL FLOWER I. Results HRM analysis of PpAG and PpTFL1 coding regions in 36 peach cultivars found one polymorphic site in each gene. PpTFL1 and PpAG SNPs were used to examine approaches to increase HRM throughput. Cultivars with SNPs could be reliably detected in pools of twelve genotypes. COLD-PCR was found to increase the sensitivity of HRM analysis of pooled samples, but worked best with small amplicons. Examination of QMC-PCR demonstrated that primary PCR products for further analysis could be produced from variable levels of genomic DNA. Conclusions Natural SNPs in exons of target peach genes were discovered by HRM analysis of cultivars from a southeastern US breeding program. For detecting natural or induced SNPs in larger populations, HRM efficiency can be improved by increasing sample pooling and template production through approaches such as COLD-PCR and QMC-PCR. Technical advances developed to improve clinical diagnostics can play a role in the targeted mutation breeding of crops.
Full Text Available Chrysanthemum morifolium is an important floral crop that is cultivated worldwide. However, due to a lack of genomic resources, very little information is available concerning the molecular mechanisms of flower development in chrysanthemum.The transcriptomes of chrysanthemum vegetative buds, floral buds and buds were sequenced using Illumina paired-end sequencing technology. A total of 15.4 Gb of reads were assembled into 91,367 unigenes with an average length of 739 bp. A total of 43,137 unigenes showed similarity to known proteins in the Swissprot or NCBI non-redundant protein databases. Additionally, 25,424, 24,321 and 13,704 unigenes were assigned to 56 gene ontology (GO categories, 25 EuKaryotic Orthologous Groups (KOG categories, and 285 Kyoto Encyclopedia of Genes and Genomes (KEGG pathways, respectively. A total of 1,876 differentially expressed genes (DEGs (1,516 up-regulated, 360 down-regulated were identified between vegetative buds and floral buds, and 3,300 DEGs (1,277 up-regulated, 1,706 down-regulated were identified between floral buds and buds. Many genes encoding important transcription factors (e.g., AP2, MYB, MYC, WRKY, NAC and CRT as well as proteins involved in carbohydrate metabolism, protein kinase activity, plant hormone signal transduction, and the defense responses, among others, were considerably up-regulated in floral buds. Genes involved in the photoperiod pathway and flower organ determination were also identified. These genes represent important candidate genes for molecular cloning and functional analysis to study flowering regulation in chrysanthemum.This comparative transcriptome analysis revealed significant differences in gene expression and signaling pathway components between the vegetative buds, floral buds and buds of Chrysanthemum morifolium. A wide range of genes was implicated in regulating the phase transition from vegetative to reproductive growth. These results should aid researchers in the study of
Liu, Hua; Sun, Ming; Du, Dongliang; Pan, Huitang; Cheng, Tangren; Wang, Jia; Zhang, Qixiang
Chrysanthemum morifolium is an important floral crop that is cultivated worldwide. However, due to a lack of genomic resources, very little information is available concerning the molecular mechanisms of flower development in chrysanthemum. The transcriptomes of chrysanthemum vegetative buds, floral buds and buds were sequenced using Illumina paired-end sequencing technology. A total of 15.4 Gb of reads were assembled into 91,367 unigenes with an average length of 739 bp. A total of 43,137 unigenes showed similarity to known proteins in the Swissprot or NCBI non-redundant protein databases. Additionally, 25,424, 24,321 and 13,704 unigenes were assigned to 56 gene ontology (GO) categories, 25 EuKaryotic Orthologous Groups (KOG) categories, and 285 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. A total of 1,876 differentially expressed genes (DEGs) (1,516 up-regulated, 360 down-regulated) were identified between vegetative buds and floral buds, and 3,300 DEGs (1,277 up-regulated, 1,706 down-regulated) were identified between floral buds and buds. Many genes encoding important transcription factors (e.g., AP2, MYB, MYC, WRKY, NAC and CRT) as well as proteins involved in carbohydrate metabolism, protein kinase activity, plant hormone signal transduction, and the defense responses, among others, were considerably up-regulated in floral buds. Genes involved in the photoperiod pathway and flower organ determination were also identified. These genes represent important candidate genes for molecular cloning and functional analysis to study flowering regulation in chrysanthemum. This comparative transcriptome analysis revealed significant differences in gene expression and signaling pathway components between the vegetative buds, floral buds and buds of Chrysanthemum morifolium. A wide range of genes was implicated in regulating the phase transition from vegetative to reproductive growth. These results should aid researchers in the study of flower
However, there has been no attempt to optimize the investment in nectar production along with that in floral display. One of the key questions that arises is whether the floral display will evolve to be an honest indicator of nectar reward. We use a mathematical model to cooptimize the investments in nectar and floral display ...
James H. Cane
Pollinators, even floral generalists (=polyleges), typically specialize during individual foraging bouts, infrequently switching between floral hosts. Such transient floral constancy restricts pollen flow, and thereby gene flow, to conspecific flowers in mixed plant communities. Where incipient flowering species meet, however, weak cross-fertility and often similar...
Jun 3, 2009 ... establish an orchid floral ontogenic model. Key words: Dendrobium crumenatum, Differentially Expressed Genes (DEGs), floral organs. INTRODUCTION. The floral developments of orchids are unique and more complicated than the understanding of conventional monocotyledonous flowers. Orchid flowers ...
Domingo, Josep M.
In 1859, the very same stimulus that drove the ambition to create Barcelona’s Eixample (“enlargement”) design by urban planner Cerdà served to “restore” the Jocs Florals in Barcelona, a symbolic complement which quite calculatedly evoked powerful arguments of historical legitimacy which the Catalans of the mid-19th century would harness for their latter-day aims. Under the authority of the Romantic gothic revival, in 1859 the Jocs Florals, were, in fact, a meteoric, sumptuous chapter...
Liliana M Cano
Full Text Available Pucciniamonoica is a spectacular plant parasitic rust fungus that triggers the formation of flower-like structures (pseudoflowers in its Brassicaceae host plant Boecherastricta. Pseudoflowers mimic in shape, color, nectar and scent co-occurring and unrelated flowers such as buttercups. They act to attract insects thereby aiding spore dispersal and sexual reproduction of the rust fungus. Although much ecological research has been performed on P. monoica-induced pseudoflowers, this system has yet to be investigated at the molecular or genomic level. To date, the molecular alterations underlying the development of pseudoflowers and the genes involved have not been described. To address this, we performed gene expression profiling to reveal 256 plant biological processes that are significantly altered in pseudoflowers. Among these biological processes, plant genes involved in cell fate specification, regulation of transcription, reproduction, floral organ development, anthocyanin (major floral pigments and terpenoid biosynthesis (major floral volatile compounds were down-regulated in pseudoflowers. In contrast, plant genes involved in shoot, cotyledon and leaf development, carbohydrate transport, wax biosynthesis, cutin transport and L-phenylalanine metabolism (pathway that results in phenylethanol and phenylacetaldehyde volatile production were up-regulated. These findings point to an extensive reprogramming of host genes by the rust pathogen to induce floral mimicry. We also highlight 31 differentially regulated plant genes that are enriched in the biological processes mentioned above, and are potentially involved in the formation of pseudoflowers. This work illustrates the complex perturbations induced by rust pathogens in their host plants, and provides a starting point for understanding the molecular mechanisms of pathogen-induced floral mimicry.
Hinchliffe, Philip; Greene, Nicholas P; Paterson, Neil G; Crow, Allister; Hughes, Colin; Koronakis, Vassilis
Periplasmic adaptor proteins are key components of bacterial tripartite efflux pumps. The 2.85 Å resolution structure of an MFS (major facilitator superfamily) pump adaptor, Aquifex aeolicus EmrA, shows linearly arranged α-helical coiled-coil, lipoyl, and β-barrel domains, but lacks the fourth membrane-proximal domain shown in other pumps to interact with the inner membrane transporter. The adaptor α-hairpin, which binds outer membrane TolC, is exceptionally long at 127 Å, and the β-barrel contains a conserved disordered loop. The structure extends the view of adaptors as flexible, modular components that mediate diverse pump assembly, and suggests that in MFS tripartite pumps a hexamer of adaptors could provide a periplasmic seal. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.
Ianis G. Matsoukas; Ianis G. Matsoukas
The juvenile-to-adult and vegetative-to-reproductive phase transitions are major determinants of plant reproductive success and adaptation to the local environment. Understanding the intricate molecular genetic and physiological machinery by which environment regulates juvenility and floral signal transduction has significant scientific and economic implications. Sugars are recognized as important regulatory molecules that regulate cellular activity at multiple levels, from transcription and ...
Prof. Adipala Ekwamu
May 6, 2013 ... the visitor foraging for pollen, nectar, both or other floral parts. For the observations in Zambia, we determined the visiting time per inflorescence for the 2 most abundant visitors. Each time when the most abundant visitor came; we timed how long it stayed on an inflorescence and on a tree, for. 104 random ...
Higuchi, Yohei; Hisamatsu, Tamotsu
Chrysanthemums require repeated cycles of short-day (SD) photoperiod for successful anthesis, but their vegetative state is strictly maintained under long-day (LD) or night-break (NB) conditions. We have previously demonstrated that photoperiodic flowering of a wild diploid chrysanthemum (Chrysanthemum seticuspe f. boreale) is controlled by a pair of systemic floral regulators, florigen (CsFTL3) and anti-florigen (CsAFT), produced in the leaves. Here, we report the functional characterisation of a local floral regulator, CsTFL1, a chrysanthemum orthologue of TERMINAL FLOWER 1 gene in Arabidopsis. Constitutive expression of CsTFL1 in C. seticuspe (CsTFL1-ox) resulted in extremely late flowering under SD and prevented up-regulation of floral meristem identity genes in shoot tips and leaves. Bimolecular fluorescence complementation assay showed that both CsTFL1 and CsFTL3 interacted with CsFDL1, a bZIP transcription factor FD homologue, in the nucleus. The transient gene expression assay indicated that CsTFL1 suppresses flowering by directly antagonising the flower inductive activity of the CsFTL3-CsFDL1 complex. Our results suggest that strict maintenance of vegetative state under non-inductive photoperiod is achieved by the coordinated action of both the systemic floral inhibitor and local floral inhibitor CsTFL1, which is constitutively expressed in shoot tips. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Ianis G. Matsoukas
Full Text Available The juvenile-to-adult and vegetative-to-reproductive phase transitions are major determinants of plant reproductive success and adaptation to the local environment. Understanding the intricate molecular genetic and physiological machinery by which environment regulates juvenility and floral signal transduction has significant scientific and economic implications. Sugars are recognized as important regulatory molecules that regulate cellular activity at multiple levels, from transcription and translation to protein stability and activity. Molecular genetic and physiological approaches have demonstrated different aspects of carbohydrate involvement and its interactions with other signal transduction pathways in regulation of the juvenile-to-adult and vegetative-to-reproductive phase transitions. Sugars regulate juvenility and floral signal transduction through their function as energy sources, osmotic regulators and signalling molecules. Interestingly, sugar signalling has been shown to involve extensive connections with phytohormone signalling. This includes interactions with phytohormones that are also important for the orchestration of developmental phase transitions, including gibberellins, abscisic acid, ethylene and brassinosteroids. This article highlights the potential roles of sugar-hormone interactions in regulation of floral signal transduction, with particular emphasis on Arabidopsis thaliana mutant phenotypes, and suggests possible directions for future research.
Matsoukas, Ianis G
NOMENCLATURE The following nomenclature will be used in this article: Names of genes are written in italicized upper-case letters, e.g., ABI4.Names of proteins are written in non-italicized upper-case letters, e.g., ABI4.Names of mutants are written in italicized lower-case letters, e.g., abi4. The juvenile-to-adult and vegetative-to-reproductive phase transitions are major determinants of plant reproductive success and adaptation to the local environment. Understanding the intricate molecular genetic and physiological machinery by which environment regulates juvenility and floral signal transduction has significant scientific and economic implications. Sugars are recognized as important regulatory molecules that regulate cellular activity at multiple levels, from transcription and translation to protein stability and activity. Molecular genetic and physiological approaches have demonstrated different aspects of carbohydrate involvement and its interactions with other signal transduction pathways in regulation of the juvenile-to-adult and vegetative-to-reproductive phase transitions. Sugars regulate juvenility and floral signal transduction through their function as energy sources, osmotic regulators and signaling molecules. Interestingly, sugar signaling has been shown to involve extensive connections with phytohormone signaling. This includes interactions with phytohormones that are also important for the orchestration of developmental phase transitions, including gibberellins, abscisic acid, ethylene, and brassinosteroids. This article highlights the potential roles of sugar-hormone interactions in regulation of floral signal transduction, with particular emphasis on Arabidopsis thaliana mutant phenotypes, and suggests possible directions for future research.
Jaudal, Mauren; Monash, Jacob; Zhang, Lulu; Wen, Jiangqi; Mysore, Kirankumar S; Macknight, Richard; Putterill, Joanna
The MADS-domain transcription factor SHORT VEGETATIVE PHASE plays a key role as a repressor of the transition to flowering and as a regulator of early floral development in Arabidopsis thaliana (Arabidopsis). However, no flowering-time repressors have been functionally identified in the model legume Medicago truncatula (Medicago). In this study, phylogenetic analysis of two closely-related MtSVP-like sequences, MtSVP1 and MtSVP2, showed that their predicted proteins clustered together within the eudicot SVP clade. To determine if the MtSVP-like genes have a role in flowering, they were functionally characterized in Medicago and Arabidopsis. Transcripts of both MtSVP genes were abundant and broadly expressed in vegetative tissues but were detected at much lower levels in flowers in Medicago. Over-expression of the MtSVP genes in Arabidopsis resulted in delayed flowering and flowers with many abnormal phenotypes such as leafy sepals, changes to floral organ number and longer pedicels than the wild type. By contrast, in transgenic Medicago, over-expression of MtSVP1 resulted in alterations to flower development, but did not alter flowering time, suggesting that MtSVP1 may not function to repress the transition to flowering in Medicago.
Full Text Available The isothermal forging process is an effective method to manufacture complex-shaped components of hard-to-work materials, such as magnesium alloys. This study investigates the isothermal forging process of an MB26 magnesium alloy adaptor with three branches. The results show that two-step forging process is appropriate to form the adaptor forging, which not only improves the filling quality but also reduces the forging load compared with one-step forging process. Moreover, the flow line is distributed along the contour of the complex-shaped adaptor forging.
Full Text Available ) Open .csml file with CIOPlayer Open .csml file with CIOPlayer - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ... ...18706831 Signalling adaptors used by Toll-like receptors: an update. Kenny EF, O'Ne...ill LA. Cytokine. 2008 Sep;43(3):342-9. Epub 2008 Aug 15. (.png) (.svg) (.html) (.csml) Show Signalling adaptors use...d by Toll-like receptors: an update. PubmedID 18706831 Title Signalling adaptors used by Toll-like r
Full Text Available The selective transport of proteins or lipids by vesicular transport is a fundamental process supporting cellular physiology. The budding process involves cargo sorting and vesicle formation at the donor membrane and constitutes an important process in vesicular transport. This process is particularly important for the polarized sorting in epithelial cells, in which the cargo molecules need to be selectively sorted and transported to two distinct destinations, the apical or basolateral plasma membrane. Adaptor protein (AP-1, a member of the AP complex family, which includes the ubiquitously expressed AP-1A and the epithelium-specific AP-1B, regulates polarized sorting at the trans-Golgi network and/or at the recycling endosomes. A growing body of evidence, especially from studies using model organisms and animals, demonstrates that the AP-1-mediated polarized sorting supports the development and physiology of multi-cellular units as functional organs and tissues (e.g., cell fate determination, inflammation and gut immune homeostasis. Furthermore, a possible involvement of AP-1B in the pathogenesis of human diseases, such as Crohn’s disease and cancer, is now becoming evident. These data highlight the significant contribution of AP-1 complexes to the physiology of multicellular organisms, as master regulators of polarized sorting in epithelial cells.
Risseeuw, Eddy; Venglat, Prakash; Xiang, Daoquan; Komendant, Kristina; Daskalchuk, Tim; Babic, Vivijan; Crosby, William; Datla, Raju
Plants are unique in their ability to continuously produce new meristems and organ primordia. In Arabidopsis, the transcription factor LEAFY (LFY) functions as a master regulator of a gene network that is important for floral meristem and organ specification. UNUSUAL FLORAL ORGANS (UFO) is a co-activator of LEAFY and is required for proper activation of APETALA3 in the floral meristem during the specification of stamens and petals. The ufo mutants display defects in other parts of the flower and the inflorescence, suggestive of additional roles. Here we show that the normal determinacy of the developing Arabidopsis leaves is affected by the expression of a gain-of-function UFO fusion protein with the VP16 transcriptional activator domain. In these lines, the rosette and cauline leaf primordia exhibit reiterated serration, and upon flowering produce ectopic meristems that develop into flowers, bract leaves and inflorescences. These striking phenotypes reveal that developing leaves maintain the competency to initiate flower and inflorescence programs. Furthermore, the gain-of-function phenotypes are dependent on LFY and the SEPALLATA (SEP) MADS-box transcription factors, indicative of their functional interactions with UFO. The findings of this study also suggest that UFO promotes the establishment of the lateral meristems and primordia in the peripheral zone of the apical and floral meristems by enhancing the activity of LFY. These novel phenotypes along with the mutant phenotypes of UFO orthologs in other plant species suggest a broader function for UFO in plants.
Full Text Available Plants are unique in their ability to continuously produce new meristems and organ primordia. In Arabidopsis, the transcription factor LEAFY (LFY functions as a master regulator of a gene network that is important for floral meristem and organ specification. UNUSUAL FLORAL ORGANS (UFO is a co-activator of LEAFY and is required for proper activation of APETALA3 in the floral meristem during the specification of stamens and petals. The ufo mutants display defects in other parts of the flower and the inflorescence, suggestive of additional roles. Here we show that the normal determinacy of the developing Arabidopsis leaves is affected by the expression of a gain-of-function UFO fusion protein with the VP16 transcriptional activator domain. In these lines, the rosette and cauline leaf primordia exhibit reiterated serration, and upon flowering produce ectopic meristems that develop into flowers, bract leaves and inflorescences. These striking phenotypes reveal that developing leaves maintain the competency to initiate flower and inflorescence programs. Furthermore, the gain-of-function phenotypes are dependent on LFY and the SEPALLATA (SEP MADS-box transcription factors, indicative of their functional interactions with UFO. The findings of this study also suggest that UFO promotes the establishment of the lateral meristems and primordia in the peripheral zone of the apical and floral meristems by enhancing the activity of LFY. These novel phenotypes along with the mutant phenotypes of UFO orthologs in other plant species suggest a broader function for UFO in plants.
Risseeuw, Eddy; Venglat, Prakash; Xiang, Daoquan; Komendant, Kristina; Daskalchuk, Tim; Babic, Vivijan; Crosby, William; Datla, Raju
Plants are unique in their ability to continuously produce new meristems and organ primordia. In Arabidopsis, the transcription factor LEAFY (LFY) functions as a master regulator of a gene network that is important for floral meristem and organ specification. UNUSUAL FLORAL ORGANS (UFO) is a co-activator of LEAFY and is required for proper activation of APETALA3 in the floral meristem during the specification of stamens and petals. The ufo mutants display defects in other parts of the flower and the inflorescence, suggestive of additional roles. Here we show that the normal determinacy of the developing Arabidopsis leaves is affected by the expression of a gain-of-function UFO fusion protein with the VP16 transcriptional activator domain. In these lines, the rosette and cauline leaf primordia exhibit reiterated serration, and upon flowering produce ectopic meristems that develop into flowers, bract leaves and inflorescences. These striking phenotypes reveal that developing leaves maintain the competency to initiate flower and inflorescence programs. Furthermore, the gain-of-function phenotypes are dependent on LFY and the SEPALLATA (SEP) MADS-box transcription factors, indicative of their functional interactions with UFO. The findings of this study also suggest that UFO promotes the establishment of the lateral meristems and primordia in the peripheral zone of the apical and floral meristems by enhancing the activity of LFY. These novel phenotypes along with the mutant phenotypes of UFO orthologs in other plant species suggest a broader function for UFO in plants. PMID:24376756
Full Text Available El propósito de este trabajo fue caracterizar las fases fenológicas florales y determinar los visitantes florales en una población natural de Drimys granadensis (Winteraceae ubicada en Altos de Yerbabuena (2850 m, cerros orientales de la Sabana de Bogotá, (Colombia. El desarrollo fenológico floral duró 9.5 días cuando la floración ocurrió en época soleada, 12.5 días en época lluviosa y 16 días cuando se excluyeron a los visitantes florales mediante embolsado. Se realizaron observaciones del recurso utilizado, fase fenólogica de la flor visitada y cargas polínicas en los visitante florales, los cuales correspondieron a 6 órdenes, 21 familias y 29 morfoespecies de insectos. Cuatro especies de coleópteros y dos de dípteros fueron considerados posibles polinizadores por su abundancia y carga de polen. Los resultados obtenidos se discuten en relación con aquellos reportados en otras especies del género Drimys y de la familia Winteraceae.
Full Text Available El propósito de este trabajo fue caracterizar las fases fenológicas florales y determinar los visitantes florales en una población natural de Drimys granadensis (nombre común: canelo; Winteraceae ubicada en Altos de Yerbabuena (2.850 m, cerros orientales de la Sabana de Bogotá, (Colombia. El desarrollo fenológico floral duró 9,5 días cuando la floración ocurrió en época soleada, 12,5 días en época lluviosa y 16 días cuando se excluyeron a los visitantes florales mediante embolsado. Se realizaron observaciones del recurso utilizado, fase fenólogica de la flor visitada y cargas polínicas en los visitante florales, los cuales correspondieron a seis órdenes, 21 familias y 29 morfoespecies de insectos. Cuatro especies de coleópteros y dos de dípteros fueron considerados posibles polinizadores por su abundancia y carga de polen. Los resultados obtenidos se discuten en relación con aquellos reportados en otras especies del género Drimys y de la familia Winteraceae.
Liew, Lim Chee; Singh, Mohan B; Bhalla, Prem L
Legumes, with their unique ability to fix atmospheric nitrogen, play a vital role in ensuring future food security and mitigating the effects of climate change because they use less fossil energy and produce less greenhouse gases compared with N-fertilized systems. Grain legumes are second only to cereal crops as a source of human and animal food, and they contribute approximately one third of the protein consumed by the human population. The productivity of seed crops, such as grain legumes, is dependent on flowering. Despite the genetic variation and importance of flowering in legume production, studies of the molecular pathways that control flowering in legumes are limited. Recent advances in genomics have revealed that legume flowering pathways are divergent from those of such model species as Arabidopsis thaliana. Here, we discuss the current understanding of flowering time regulation in legumes and highlight the unique and conserved features of floral evocation in legumes. © 2014 Institute of Botany, Chinese Academy of Sciences.
Moore, Matthew Robert; Jameson, Mary Liz
The scarab beetle tribe Cyclocephalini (Coleoptera: Scarabaeidae: Dynastinae) is the second largest tribe of rhinoceros beetles, with nearly 500 described species. This diverse group is most closely associated with early diverging angiosperm groups (the family Nymphaeaceae, magnoliid clade, and monocots), where they feed, mate, and receive the benefit of thermal rewards from the host plant. Cyclocephaline floral association data have never been synthesized, and a comprehensive review of this ecological interaction was necessary to promote research by updating nomenclature, identifying inconsistencies in the data, and reporting previously unpublished data. Based on the most specific data, at least 97 cyclocephaline beetle species have been reported from the flowers of 58 plant genera representing 17 families and 15 orders. Thirteen new cyclocephaline floral associations are reported herein. Six cyclocephaline and 25 plant synonyms were reported in the literature and on beetle voucher specimen labels, and these were updated to reflect current nomenclature. The valid names of three unavailable plant host names were identified. We review the cyclocephaline floral associations with respect to inferred relationships of angiosperm orders. Ten genera of cyclocephaline beetles have been recorded from flowers of early diverging angiosperm groups. In contrast, only one genus, Cyclocephala, has been recorded from dicot flowers. Cyclocephaline visitation of dicot flowers is limited to the New World, and it is unknown whether this is evolutionary meaningful or the result of sampling bias and incomplete data. The most important areas for future research include: (1) elucidating the factors that attract cyclocephalines to flowers including floral scent chemistry and thermogenesis, (2) determining whether cyclocephaline dicot visitation is truly limited to the New World, and (3) inferring evolutionary relationships within the Cyclocephalini to rigorously test vicarance hypotheses
Fathers, Kelly E
The Crk adaptor proteins (CrkI, CrkII and CrkL) play an important role during cellular signalling by mediating the formation of protein-protein complexes and are involved in cellular migration, invasion, and adhesion...
Fathers, Kelly E
The Crk adaptor proteins (CrkI, CrkII and CrkL) play an important role during cellular signalling by mediating the formation of protein-protein complexes and are involved in cellular migration, invasion, and adhesion...
Coon, Brian G.; Burgner, John; Camonis, Jacques H.; Aguilar, R. Claudio
Abnormalities in the process of endocytosis are classically linked to malignant transformation through the deficient down-regulation of signaling receptors. The present study describes a non-classical mechanism that does not require internalization by which endocytic proteins affect cell migration and basement membrane invasion. Specifically, we found that the endocytic adaptor epsin binds and regulates the biological properties of the signaling molecule RalBP1 (Ral-binding protein 1). Epsin interacted with the N terminus of RalBP1 via its characteristic epsin N-terminal homology (ENTH) domain. A combination of siRNA-mediated knock-down and transfection of siRNA-resistant constructs in fibrosarcoma cells demonstrated that impairment of the epsin-RalBP1 interaction led to cell migration and basement membrane invasion defects. We found the ENTH domain was necessary and sufficient to sustain normal cell migration and invasion. Because all the epsin endocytic motifs reside in the C-terminal part of the molecule, these results suggest that this novel regulatory circuit does not require endocytosis. In addition, cells depleted of epsin-RalBP1 complex displayed deficient activation of Rac1 and Arf6 suggesting a signaling function for this novel interaction. Further, overexpression of either epsin or RalBP1 enhanced migration and invasion of fibrosarcoma cells. Collectively, our results indicate that epsin regulates RalBP1 function in Rac1- and Arf6-dependent pathways to ultimately affect cell migration and invasion. We propose that the observed up-regulation of both epsin and RalBP1 in certain cancers contributes to their invasive characteristics. PMID:20709745
Dormont, L; Delle-Vedove, R; Bessière, J-M; Schatz, B
Polymorphism of floral signals, such as colour and odour, is widespread in flowering plants and often considered to be adaptive, reflecting various pollinator preferences for particular floral traits. Several authors have recently hypothesized that particular associations exist between floral colour and scent, which would result from shared biochemistry between these two floral traits. In this study, we compared the chemical composition of floral volatiles emitted by white- and purple-flowered morphs of three different orchid species, including two food-deceptive species (Orchis mascula and Orchis simia) and a food-rewarding species (Anacamptis coriophora fragrans). We found clear interspecific differences in floral odours. As expected from their pollination strategy, the two deceptive orchids showed high inter-individual variation of floral volatiles, whereas the food-rewarding A. c. fragrans showed low variation of floral scent. Floral volatiles did not differ overall between white- and coloured-flowered morphs in O. mascula and A. c. fragrans, while O. simia exhibited different volatile profiles between the two colour morphs. However, a detailed analysis restricted to benzenoid compounds (which are associated with the production of floral anthocyanin pigments) showed that white inflorescences emitted more volatiles of the shikimic pathway than coloured ones, both for O. mascula and O. simia. These results are consistent with the current hypothesis that shared biochemistry creates pleiotropic links between floral colour and scent. Whether intraspecific variation of floral signals actually affects pollinator attraction and influences the reproductive success of these orchids remains to be determined. Copyright © 2014 Elsevier Ltd. All rights reserved.
Full Text Available MicroRNAs are small noncoding RNAs, which regulate the expression of protein coding transcripts through mRNA degradation or translational inhibition. Numerous reports have highlighted the role of miRNAs in regulating cell death pathways including the expression of genes involved in the induction of apoptosis. Tumor necrosis factor alpha (TNF-α is a proinflammatory cytokine which can send pro-death signals through its receptor TNFR1. Diverse adaptor molecules including DENN/MADD adaptor protein have been shown to modulate TNF-α pro-death signaling via recruitment of MAP kinases to TNFR1 and activation of pro-survival NFκB signaling. Herein, we investigated the role of microRNA-181 (miR-181 in regulating DENN/MADD expression levels and its subsequent effects on TNF-α-induced cell death. Using bioinformatics analyses followed by luciferase reporter assays we showed that miR-181 interacts with the 3' UTR of DENN/MADD transcripts. miR-181 overexpression also led to decreased endogenous DENN/MADD mRNA levels in L929 murine fibroblasts. Flow cytometric analysis of miR-181 transfected cells showed this miRNA accentuates mitochondrial membrane potential loss caused by TNF-α. These findings were associated with enhanced apoptosis of L929 cells following TNF-α treatment. Overall, these data point to the potential role of miR-181 in regulating TNF-α pro-death signaling, which could be of importance from pathogenesis and therapeutic perspectives in inflammatory disorders associated with tissue degeneration and cell death.
Full Text Available Abstract Background MADS domain transcription factors play important roles in various developmental processes in flowering plants. Members of this family play a prominent role in the transition to flowering and the specification of floral organ identity. Several studies reported mRNA expression patterns of the genes encoding these MADS domain proteins, however, these studies do not provide the necessary information on the temporal and spatial localisation of the proteins. We have made GREEN FLUORESCENT PROTEIN (GFP translational fusions with the four MADS domain proteins SEPALLATA3, AGAMOUS, FRUITFULL and APETALA1 from the model plant Arabidopsis thaliana and analysed the protein localisation patterns in living plant tissues by confocal laser scanning microscopy (CLSM. Results We unravelled the protein localisation patterns of the four MADS domain proteins at a cellular and subcellular level in inflorescence and floral meristems, during development of the early flower bud stages, and during further differentiation of the floral organs. The protein localisation patterns revealed a few deviations from known mRNA expression patterns, suggesting a non-cell autonomous action of these factors or alternative control mechanisms. In addition, we observed a change in the subcellular localisation of SEPALLATA3 from a predominantly nuclear localisation to a more cytoplasmic localisation, occurring specifically during petal and stamen development. Furthermore, we show that the down-regulation of the homeodomain transcription factor WUSCHEL in ovular tissues is preceded by the occurrence of both AGAMOUS and SEPALLATA3 proteins, supporting the hypothesis that both proteins together suppress WUSCHEL expression in the ovule. Conclusion This approach provides a highly detailed in situ map of MADS domain protein presence during early and later stages of floral development. The subcellular localisation of the transcription factors in the cytoplasm, as observed at
Pan, Shujuan; Wang, Ruoning; Zhou, Xi; He, Guangan; Koomen, John; Kobayashi, Ryuji; Sun, Le; Corvera, Joe; Gallick, Gary E; Kuang, Jian
The conserved adaptor protein Alix, also called AIP1 or Hp95, promotes flattening and alignment of cultured mammalian fibroblasts; however, the mechanism by which Alix regulates fibroblast morphology is not understood. Here we demonstrate that Alix in WI38 cells, which require Alix expression for maintaining typical fibroblast morphology, associates with filamentous actin (F-actin) and F-actin-based structures lamellipodia and stress fibers. Reducing Alix expression by small interfering RNA (siRNA) decreases F-actin content and inhibits stress fiber assembly. In cell-free systems, Alix directly interacts with F-actin at both the N-terminal Bro1 domain and the C-terminal proline-rich domain. In Alix immunoprecipitates from WI38 cell lysates, actin is the most abundant partner protein of Alix. In addition, the N-terminal half of the middle region of Alix binds cortactin, an activator of the ARP2/3 complex-mediated initiation of actin polymerization. Alix is required for lamellipodial localization of cortactin. The C-terminal half of the middle region of Alix interacts with alpha-actinin, a key factor that bundles F-actin in stress fibers. Alix knockdown decreases the amount of alpha-actinin that associates with F-actin. These findings establish crucial involvement of Alix in actin cytoskeleton assembly.
Full Text Available The goal of developing treatments for central nervous system (CNS injuries is becoming more attainable with the recent identification of various drugs that can repair damaged axons. These discoveries have stemmed from screening efforts, large expression datasets and an improved understanding of the cellular and molecular biology underlying axon growth. It will be important to continue searching for new compounds that can induce axon repair. Here we describe how a family of adaptor proteins called 14-3-3s can be targeted using small molecule drugs to enhance axon outgrowth and regeneration. 14-3-3s bind to many functionally diverse client proteins to regulate their functions. We highlight the recent discovery of the axon-growth promoting activity of fusicoccin-A, a fungus-derived small molecule that stabilizes 14-3-3 interactions with their client proteins. Here we discuss how fusicoccin-A could serve as a starting point for the development of drugs to induce CNS repair.
He, X; Li, Y; Schembri-King, J; Jakes, S; Hayashi, J
Human Lnk (hLnk) is an adaptor protein with multiple functional domains that regulates T cell activation signaling. In order to identify cellular Lnk binding partners, a yeast two-hybrid screening of human spleen cDNA library was carried out using human hLnk as bait. A polypeptide sequence identical to the C-terminal segment of the actin binding protein (ABP-280) was identified as a hLnk binding protein. The expressed hLnk and the FLAG tagged C-terminal 673 amino acid residues of ABP-280 or the endogenous ABP-280 in COS-7 cells could be co-immunoprecipitated using antibodies either to hLnk, FLAG or ABP-280, respectively. Furthermore, immunofluorescence confocal microscope showed that hLnk and ABP-280 co-localized at the plasma membrane and at juxtanuclear region of COS-7 cells. In Jurkat cells, the endogenous hLnk also associates with the endogenous ABP-280 indicating that the association of these two proteins is physiological. The interacting domains of both proteins were mapped using yeast two-hybrid assays. Our results indicate that hLnk binds to the residues 2006-2454 (repeats 19-23C) of ABP-280. The domain in hLnk that associates with ABP-280 was mapped to an interdomain region of 56 amino acids between pleckstrin homology and Src homology 2 domains. These results suggest that hLnk may exert its regulatory role through its association with ABP-280.
Full Text Available Mediator is a conserved multi-protein complex that plays an important role in regulating transcription by mediating interactions between transcriptional activator proteins and RNA polymerase II. Much evidence exists that Mediator plays a constitutive role in the transcription of all genes transcribed by RNA polymerase II. However, evidence is mounting that specific Mediator subunits may control the developmental regulation of specific subsets of RNA polymerase II-dependent genes. Although the Mediator complex has been extensively studied in yeast and mammals, only a few reports on Mediator function in flowering time control of plants, little is known about Mediator function in floral organ identity. Here we show that in Arabidopsis thaliana, MEDIATOR SUBUNIT 18 (MED18 affects flowering time and floral organ formation through FLOWERING LOCUS C (FLC and AGAMOUS (AG. A MED18 loss-of-function mutant showed a remarkable syndrome of later flowering and altered floral organ number. We show that FLC and AG mRNA levels and AG expression patterns are altered in the mutant. Our results support parallels between the regulation of FLC and AG and demonstrate a developmental role for Mediator in plants.
Shi, Chun-Lin; Stenvik, Grethe-Elisabeth; Vie, Ane Kjersti; Bones, Atle M; Pautot, Véronique; Proveniers, Marcel; Aalen, Reidunn B; Butenko, Melinka A
Floral organ abscission in Arabidopsis thaliana is regulated by the putative ligand-receptor system comprising the signaling peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) and the two receptor-like kinases HAESA and HAESA-LIKE2. The IDA signaling pathway presumably activates a MITOGEN-ACTIVATED PROTEIN KINASE (MAPK) cascade to induce separation between abscission zone (AZ) cells. Misexpression of IDA effectuates precocious floral abscission and ectopic cell separation in latent AZ cell regions, which suggests that negative regulators are in place to prevent unrestricted and untimely AZ cell separation. Through a screen for mutations that restore floral organ abscission in ida mutants, we identified three new mutant alleles of the KNOTTED-LIKE HOMEOBOX gene BREVIPEDICELLUS (BP)/KNOTTED-LIKE FROM ARABIDOPSIS THALIANA1 (KNAT1). Here, we show that bp mutants, in addition to shedding their floral organs prematurely, have phenotypic commonalities with plants misexpressing IDA, such as enlarged AZ cells. We propose that BP/KNAT1 inhibits floral organ cell separation by restricting AZ cell size and number and put forward a model whereby IDA signaling suppresses BP/KNAT1, which in turn allows KNAT2 and KNAT6 to induce floral organ abscission.
Walker, Kendall R; Modgil, Amit; Albrecht, David; Lomoio, Selene; Haydon, Philip G; Moss, Stephen J; Tesco, Giuseppina
Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3) is a monomeric clathrin adaptor that has been shown to regulate the trafficking of the Beta-site APP-cleaving enzyme (BACE1), which is required for production of the Alzheimer's disease (AD)-associated amyloid βpeptide. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that depletion of GGA3 results in increased BACE1 levels and activity owing to impaired lysosomal trafficking and degradation. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We report here that GGA3 deletion results in novelty-induced hyperactivity and decreased anxiety-like behaviors. Given the pivotal role of GABAergic transmission in the regulation of anxiety-like behaviors, we performed electrophysiological recordings in hippocampal slices and found increased phasic and decreased tonic inhibition in the dentate gyrus granule cells (DGGC). Moreover, we found that the number of inhibitory synapses is increased in the dentate gyrus of GGA3 null mice in further support of the electrophysiological data. Thus, the increased GABAergic transmission is a leading candidate mechanism underlying the reduced anxiety-like behaviors observed in GGA3 null mice. All together these findings suggest that GGA3 plays a key role in GABAergic transmission. Since BACE1 levels are elevated in the brain of GGA3 null mice, it is possible that at least some of these phenotypes are a consequence of increased processing of BACE1 substrates.
Albrecht, David; Lomoio, Selene; Haydon, Philip G.; Moss, Stephen J.; Tesco, Giuseppina
Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3) is a monomeric clathrin adaptor that has been shown to regulate the trafficking of the Beta-site APP-cleaving enzyme (BACE1), which is required for production of the Alzheimer’s disease (AD)-associated amyloid βpeptide. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that depletion of GGA3 results in increased BACE1 levels and activity owing to impaired lysosomal trafficking and degradation. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We report here that GGA3 deletion results in novelty-induced hyperactivity and decreased anxiety-like behaviors. Given the pivotal role of GABAergic transmission in the regulation of anxiety-like behaviors, we performed electrophysiological recordings in hippocampal slices and found increased phasic and decreased tonic inhibition in the dentate gyrus granule cells (DGGC). Moreover, we found that the number of inhibitory synapses is increased in the dentate gyrus of GGA3 null mice in further support of the electrophysiological data. Thus, the increased GABAergic transmission is a leading candidate mechanism underlying the reduced anxiety-like behaviors observed in GGA3 null mice. All together these findings suggest that GGA3 plays a key role in GABAergic transmission. Since BACE1 levels are elevated in the brain of GGA3 null mice, it is possible that at least some of these phenotypes are a consequence of increased processing of BACE1 substrates. PMID:27192432
Kendall R Walker
Full Text Available Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3 is a monomeric clathrin adaptor that has been shown to regulate the trafficking of the Beta-site APP-cleaving enzyme (BACE1, which is required for production of the Alzheimer's disease (AD-associated amyloid βpeptide. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that depletion of GGA3 results in increased BACE1 levels and activity owing to impaired lysosomal trafficking and degradation. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We report here that GGA3 deletion results in novelty-induced hyperactivity and decreased anxiety-like behaviors. Given the pivotal role of GABAergic transmission in the regulation of anxiety-like behaviors, we performed electrophysiological recordings in hippocampal slices and found increased phasic and decreased tonic inhibition in the dentate gyrus granule cells (DGGC. Moreover, we found that the number of inhibitory synapses is increased in the dentate gyrus of GGA3 null mice in further support of the electrophysiological data. Thus, the increased GABAergic transmission is a leading candidate mechanism underlying the reduced anxiety-like behaviors observed in GGA3 null mice. All together these findings suggest that GGA3 plays a key role in GABAergic transmission. Since BACE1 levels are elevated in the brain of GGA3 null mice, it is possible that at least some of these phenotypes are a consequence of increased processing of BACE1 substrates.
Hryckowian, Andrew J; Battesti, Aurelia; Lemke, Justin J; Meyer, Zachary C; Welch, Rodney A
RpoS (σ(S)), the general stress response sigma factor, directs the expression of genes under a variety of stressful conditions. Control of the cellular σ(S) concentration is critical for appropriately scaled σ(S)-dependent gene expression. One way to maintain appropriate levels of σ(S) is to regulate its stability. Indeed, σ(S) degradation is catalyzed by the ClpXP protease and the recognition of σ(S) by ClpXP depends on the adaptor protein RssB. Three anti-adaptors (IraD, IraM, and IraP) exist in Escherichia coli K-12; each interacts with RssB and inhibits RssB activity under different stress conditions, thereby stabilizing σ(S). Unlike K-12, some E. coli isolates, including uropathogenic E. coli strain CFT073, show comparable cellular levels of σ(S) during the logarithmic and stationary growth phases, suggesting that there are differences in the regulation of σ(S) levels among E. coli strains. Here, we describe IraL, an RssB anti-adaptor that stabilizes σ(S) during logarithmic phase growth in CFT073 and other E. coli and Shigella strains. By immunoblot analyses, we show that IraL affects the levels and stability of σ(S) during logarithmic phase growth. By computational and PCR-based analyses, we reveal that iraL is found in many E. coli pathotypes but not in laboratory-adapted strains. Finally, by bacterial two-hybrid and copurification analyses, we demonstrate that IraL interacts with RssB by a mechanism distinct from that used by other characterized anti-adaptors. We introduce a fourth RssB anti-adaptor found in E. coli species and suggest that differences in the regulation of σ(S) levels may contribute to host and niche specificity in pathogenic and nonpathogenic E. coli strains. Bacteria must cope with a variety of environmental conditions in order to survive. RpoS (σ(S)), the general stress response sigma factor, directs the expression of many genes under stressful conditions in both pathogenic and nonpathogenic Escherichia coli strains
Floral ontogeny of taxa of two subtribes (Labicheinae, Dialiinae) of caesalpinioid tribe Cassieae, characterized by reduced number of floral organs, was compared. All three taxa studied are distichous; Petalostylis labicheoides flowers are solitary in leaf axils, Labichea lanceolata has few-flowered racemes, and Dialium guineense has numerous-flowered cymes. The first sepal primordium in each is initiated abaxially and nonmedianly. Order of organogenesis in Petalostylis is: five sepals bidirectionally, five petals and carpel simultaneously, then five stamens bidirectionally, starting abaxially. The order in Labichea is: five sepals helically (one lagging in time), five petals unidirectionally starting abaxially, the carpel and petals concurrently, then two stamens successively, starting laterally. Order in Dialium is: five sepals bidirectionally, the single petal adaxially, and lastly the carpel and two stamens concurrently. Specializations include (1) reduction of the five sepals to four by fusion in Petalostylis and Labichea; (2) reduction of petal number to one in Dialium; (3) reduction of stamen number to two in Labichea and Dialium, and reduction of functional stamens to three in Petalostylis; and (4) an elaborate, late-developing style in Petalostylis. Floral asymmetry, another specialization, characterizes Labichea, expressed by dissimilar stamens, while the other genera have zygomorphic flowers. Floral ontogenies are compared with other taxa of Cassieae.
Hentrich, H; Kaiser, R; Gottsberger, G
We studied the reproductive biology of three sympatric Araceae species, Anthurium sagittatum, A. thrinax and Spathiphyllum humboldtii in French Guiana. The plants flowered simultaneously and were visited by scent-collecting male euglossine bees, which were apparently their major pollinators. In total, each species was visited by 3-7 euglossine species, and 2-3 euglossine species accounted for at least 80% of all flower visits, with visits being plant species-specific. Floral scent consisted of 6-10 main compounds, which made up 76-94% of the total amount of volatiles and were specific in these high amounts to each plant species. We suggest that the different floral scents lead to clear separation of the main pollinating euglossine species, providing a directed and efficient intraspecific pollen flow that results in high reproductive success. Since the simple floral (inflorescence) morphology of the studied plants does not support any morphological mechanisms to exclude visitors, as for example in euglossine-pollinated perfume orchids, floral scent might be of major importance for the reproductive isolation and sympatric occurrence of these plants.
Zhang, Feng-Ping; Yang, Ying-Jie; Yang, Qiu-Yun; Zhang, Wei; Brodribb, Tim J; Hao, Guang-You; Hu, Hong; Zhang, Shi-Bao
Floral longevity (FL) determines the balance between pollination success and flower maintenance. While a longer floral duration enhances the ability of plants to attract pollinators, it can be detrimental if it negatively affects overall plant fitness. Longer-lived leaves display a positive correlation with their dry mass per unit area, which influences leaf construction costs and physiological functions. However, little is known about the association among FL and floral dry mass per unit area (FMA) and water maintenance traits. We investigated whether increased FL might incur similar costs. Our assessment of 11 species of Paphiopedilum (slipper orchids) considered the impact of FMA and flower water-maintenance characteristics on FL. We found a positive relationship between FL and FMA. Floral longevity showed significant correlations with osmotic potential at the turgor loss and bulk modulus of elasticity but not with FA. Neither the size nor the mass per area was correlated between leaves and flowers, indicating that flower and leaf economic traits evolved independently. Therefore, our findings demonstrate a clear relationship between FL and the capacity to maintain water status in the flower. These economic constraints also indicate that extending the flower life span can have a high physiological cost in Paphiopedilum.
Márcio Silva de Souza
Full Text Available In the present work, cacauhy's (Theobroma speciosum floral biology was studied. Flower buds split their sepals at 14h reaching its maximum at 22h, but all flowers were fully opened at 6:00 h of the following morning. Stigmatic branches showed exudates, reaching maximum between 6:00 h and 10:00 h at the same day. Ligules and petal hoods were the floral parts with highest intensity of odour. Flowers were receptive along all the morning and noon of the anthesis day. Approximately 65% of the flowers were naturally pollinated, but only 0.85% of them set a fruit. Abscission occurred on its higher frequency at 6:00 h of the second day after anthesis. Controlled pollinations showed that cacauhy was self-incompatible species.Neste trabalho foi estudada a biologia floral do cacaui (Theobroma speciosum. Os botões florais romperam a suas sépalas às 14h com a maior freqüência às 22h, estando completamente abertas às 6 h da manhã seguinte. Os braços estigmáticos apresentaram exsudato, com o nível máximo entre 06 e 10 horas da manhã do mesmo dia. As lígulas mais as cógulas foram as partes florais com odor mais intenso. As flores estavam receptivas durante toda a manhã e à tarde do dia da antese. Aproximadamente 65% das flores foram naturalmente polinizadas, mas somente 0,85% formou fruto. A abscisão ocorreu com maior frequência às 6 h do segundo dia após a antese. Polinizações controladas mostraram que o cacauí é uma espécie auto-incompatível.
An attempt was made to understand the 'floral bud distortion' (FBD), an unexplored disorder prevailing in soybean. Cyto- logical behaviour of floral reproductive organs and in silico characterization of differentially expressed transcript-derived fragments (TDFs) in symptomatic and asymptomatic soybean plants were carried ...
Jun 8, 2011 ... Floral morphology. The data of floral morphology traits were from three study populations on October 2009, from which 30 flowers were taken from different individuals at random. .... structure or size of pollen grains from AM, AL and MI. ..... based on three chloroplast dna regions: patterns in the evolution of.
Floral bud distortion in soybean and incidence in Central India. V Jadhav Pravin, SS Mane, RS Nandanwar, PB Kale, MS Dudhare, MP Moharil, RG Dani. Abstract. We describe a peculiar and often harmful budding disorder in soybean, leading to huge yield loss in India. To determine the prevalence of floral distortion in ...
Eucalyptus nitens requires a sufficiently cold winter to produce flower buds. In areas in South Africa where E. nitens commercial plantations as well as breeding and production seed orchards are located, winter chilling is often insufficient for floral bud initiation. Hence, under such conditions, E. nitens floral bud and seed ...
Fuentes, Jose D.; Chamecki, Marcelo; Roulston, T.'ai; Chen, Bicheng; Pratt, Kenneth R.
Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.
Guzmán, B; Gómez, J M; Vargas, P
The association between plants and flower visitors has been historically proposed as a main factor driving the evolutionary change of both flower and pollinator phenotypes. The considerable diversity in floral morphology within the tribe Antirrhineae has been traditionally related to pollinator types. We used empirical data on the flower visitors from 59 Antirrhineae taxa from the literature and our own field surveys, which provide an opportunity to test whether flower phenotypes are reliable predictors of visitors and pollinator niches. The degree of adjustment between eight key floral traits and actual visitors was explored by testing the predictive value of inferred pollinator syndromes (i.e. suites of floral traits that characterise groups of plant species related to pollination). Actual visitors and inferred pollinator niches (categorisation of visitors' association using a modularity algorithm) were also explored using Linear Discriminant Analysis (LDA). The bee pollinator niche is correctly classified for flowers with dull corolla colour, without nectar guides, as the most important predictor. Both predictive value and statistical classification prove useful in classifying Antirrhineae taxa and the bee pollinator niche, mostly as a consequence of the high proportion of genera and taxa with occluded corollas primarily visited by bees. Our predictive approach rendered a high Positive Predictive Value (PPV) of floral traits in the diagnosis of visitors/pollinator niches. In particular, a high PPV was found for bees as both visitors and forming pollinator niches. In addition, LDA showed that four pollinator niches are well defined based on floral traits. The large number of species visited by bees irrespective of pollinator syndromes leads us to hypothesise their generalist pollinator role, despite the phenotypically specialised flowers of Antirrhineae. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.
Bowden, T A; Mansberger, A R; Lykins, L E
Over an 18-year period 16 patients with pseudomembraneous enterocolitis were treated by restoration of floral homeostasis by administration of fecal enemas when standard accepted forms of therapy had failed to resolve the disease. Thirteen of the patients responded dramatically, with decreases in diarrhea, temperature, white blood cell counts, and a rapid convalesence. Of the three patients who died, two did not have the pseudomembrane at death, and one had involvement of the small bowel. No ill effects from the fecal enemas were noted. The observation of the pseudomembrane involving only the right half of the colon in a patient with a diverting transverse colostomy indicates that the disease is a contact mucositis.
Jinn, T L; Stone, J M; Walker, J C
Abcission, the natural shedding of leaves, flowers and fruits, is a fundamental component of plant development. Abscission is a highly regulated process that occurs at distinct zones of cells that undergo enlargement and subsequent separation. Although some components of abscission, including accumulation of the hormone ethylene and cell wall-degrading enzymes, have been described, the regulatory pathways remain largely unknown. In this paper we describe a critical component required for floral organ abscission in Arabidopsis thaliana, the receptor-like protein kinase HAESA. Histochemical analysis of transgenic plants harboring a HAESA promoter:: beta-glucuronidase reporter gene and in situ RNA hybridization experiments show HAESA expression in the abscission zones where the sepals, petals, and stamens attach to the receptacle, at the base of pedicels, and at the base of petioles where leaves attach to the stem. Immunodetection, immunoprecipitation, and protein kinase activity assays reveal HAESA is a plasma membrane serine/threonine protein kinase. The reduction of function of HAESA in transgenic plants harboring an antisense construct results in delayed abscission of floral organs, and the severity of the phenotype is directly correlated with the level of HAESA protein. These results demonstrate that HAESA functions in developmentally regulated floral organ abscission.
Sakaguchi, Masakiyo; Murata, Hitoshi; Yamamoto, Ken-ichi; Ono, Tomoyuki; Sakaguchi, Yoshihiko; Motoyama, Akira; Hibino, Toshihiko; Kataoka, Ken; Huh, Nam-ho
The receptor for advanced glycation end products (RAGE) is thought to be involved in the pathogenesis of a broad range of inflammatory, degenerative and hyperproliferative diseases. It binds to diverse ligands and activates multiple intracellular signaling pathways. Despite these pivotal functions, molecular events just downstream of ligand-activated RAGE have been surprisingly unknown. Here we show that the cytoplasmic domain of RAGE is phosphorylated at Ser391 by PKCζ upon binding of ligands. TIRAP and MyD88, which are known to be adaptor proteins for Toll-like receptor-2 and -4 (TLR2/4), bound to the phosphorylated RAGE and transduced a signal to downstream molecules. Blocking of the function of TIRAP and MyD88 largely abrogated intracellular signaling from ligand-activated RAGE. Our findings indicate that functional interaction between RAGE and TLRs coordinately regulates inflammation, immune response and other cellular functions. PMID:21829704
Schaletzki, Yvonne; Kromrey, Marie-Luise; Bröderdorf, Susanne; Hammer, Elke; Grube, Markus; Hagen, Paul; Sucic, Sonja; Freissmuth, Michael; Völker, Uwe; Greinacher, Andreas; Rauch, Bernhard H; Kroemer, Heyo K; Jedlitschky, Gabriele
The multidrug resistance protein 4 (MRP4/ABCC4) has been identified as an important transporter for signalling molecules including cyclic nucleotides and several lipid mediators in platelets and may thus represent a novel target to interfere with platelet function. Besides its localisation in the plasma membrane, MRP4 has been also detected in the membrane of dense granules in resting platelets. In polarised cells it is localised at the basolateral or apical plasma membrane. To date, the mechanism of MRP4 trafficking has not been elucidated; protein interactions may regulate both the localisation and function of this transporter. We approached this issue by searching for interacting proteins by in vitro binding assays, followed by immunoblotting and mass spectrometry, and by visualising their co-localisation in platelets and haematopoietic cells. We identified the PDZ domain containing scaffold proteins ezrin-binding protein 50 (EBP50/NHERF1), postsynaptic density protein 95 (PSD95), and sorting nexin 27 (SNX27), but also the adaptor protein complex 3 subunit β3A (AP3B1) and the heat shock protein HSP90 as putative interaction partners of MRP4. The knock-down of SNX27, PSD95, and AP3B1 by siRNA in megakaryoblastic leukaemia cells led to a redistribution of MRP4 from intracellular structures to the plasma membrane. Inhibition of HSP90 led to a diminished expression and retention of MRP4 in the endoplasmic reticulum. These results indicate that MRP4 localisation and function are regulated by multiple protein interactions. Changes in the adaptor proteins can hence lead to altered localisation and function of the transporter.
Meindl, George A; Ashman, Tia-Lynn
Hyperaccumulation is the phenomenon whereby plants take up and sequester in high concentrations elements that generally are excluded from above-ground tissues. It largely is unknown whether the metals taken up by these plants are transferred to floral rewards (i.e., nectar and pollen) and, if so, whether floral visitation is affected. We grew Streptanthus polygaloides, a nickel (Ni) hyperaccumulator, in short-term Ni supplemented soils and control soils to determine whether Ni is accumulated in floral rewards and whether floral visitation is affected by growth in Ni-rich soils. We found that while supplementation of soils with Ni did not alter floral morphology or reward quantity (i.e., anther size or nectar volume), Ni did accumulate in the nectar and pollen-filled anthers-providing the first demonstration that Ni is accumulated in pollinator rewards. Further, S. polygaloides grown in Ni-supplemented soils received fewer visits per flower per hour from both bees and flies (both naïve to Ni-rich floral resources in the study area) relative to plants grown in control soils, although the probability a plant was visited initially was unaffected by Ni treatment. Our findings show that while Ni-rich floral rewards decrease floral visitation, floral visitors are not completely deterred, so some floral visitors may collect and ingest potentially toxic resources from metal-hyperaccumulating plants. In addition to broadening our understanding of the effects of metal accumulation on ecological interactions in natural populations, these results have implications for the use of insect-pollinated plants in phytoremediation.
Cardoso-Gustavson, Poliana; Campbell, Lisa M; Mazzoni-Viveiros, Solange C; de Barros, Fábio
The term colleter is applied to trichomes or emergences positioned close to developing vegetative and floral meristems that secrete a sticky, mucilaginous, and/or lipophilic exudate. Several ecological functions are attributed to these glands, but none are exclusive to colleters. Patterns of morphology and distribution of colleters may be valuable for systematics and phylogeny, especially concerning problematic and large groups such as the subtribe Pleurothallidinae, and are also essential to understand the evolution of these glands in Orchidaceae as a whole. We used scanning electron and light microscopy to examine the structure and occurrence of trichomes on bracts and sepals and in the invaginations of the external ovary wall (IEOW) in flowers in several developmental stages from species in seven genera. The exudate was composed of polysaccharides, lipophilic, and phenolic compounds. Colleters were secretory only during the development of floral organs, except for the glands in the IEOW that were also active in flowers at anthesis. After the secretory phase, fungal hyphae were found penetrating senescent trichomes. Trichome-like colleters seem to be a widespread character in Epidendroideae, and digitiform colleters are possibly the common type in this subfamily. Mucilage from IEOW colleters may aid in the establishment of symbiotic fungi necessary for seed germination. The presence of colleters in the IEOW may be a case of homeoheterotopy, in which extrafloral nectaries that produce simple sugar-based secretions (as in other orchid species) have changed to glands that produce secretions with complex polysaccharides, as in Pleurothallidinae.
Renaud, Gabriel; Stenzel, Udo; Kelso, Janet
The sequencing of libraries containing molecules shorter than the read length, such as in ancient or forensic applications, may result in the production of reads that include the adaptor, and in paired reads that overlap one another. Challenges for the processing of such reads are the accurate identification of the adaptor sequence and accurate reconstruction of the original sequence most likely to have given rise to the observed read(s). We introduce an algorithm that removes the adaptors and reconstructs the original DNA sequences using a Bayesian maximum a posteriori probability approach. Our algorithm is faster, and provides a more accurate reconstruction of the original sequence for both simulated and ancient DNA data sets, than other approaches. leeHom is released under the GPLv3 and is freely available from: https://bioinf.eva.mpg.de/leehom/ © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.
Full Text Available Plants produce nectar in their flowers as a reward for their pollinators and most of our crops depend on insect pollination, but little is known on the physiological control of nectar secretion. Jasmonates are well-known for their effects on senescence, the development and opening of flowers and on plant defences such as extrafloral nectar. Their role in floral nectar secretion has, however, not been explored so far. We investigated whether jasmonates have an influence on floral nectar secretion in oil-seed rape, Brassica napus. The floral tissues of this plant produced jasmonic acid (JA endogenously, and JA concentrations peaked shortly before nectar secretion was highest. Exogenous application of JA to flowers induced nectar secretion, which was suppressed by treatment with phenidone, an inhibitor of JA synthesis. This effect could be reversed by additional application of JA. Jasmonoyl-isoleucine and its structural mimic coronalon also increased nectar secretion. Herbivory or addition of JA to the leaves did not have an effect on floral nectar secretion, demonstrating a functional separation of systemic defence signalling from reproductive nectar secretion. Jasmonates, which have been intensively studied in the context of herbivore defences and flower development, have a profound effect on floral nectar secretion and, thus, pollination efficiency in B. napus. Our results link floral nectar secretion to jasmonate signalling and thereby integrate the floral nectar secretion into the complex network of oxylipid-mediated developmental processes of plants.
Full Text Available Toll-like receptor 7 (TLR7 plays a vital role in the immune response to ssRNA viruses such as human rhinovirus (HRV and Influenza, against which there are currently no treatments or vaccines with long term efficacy available. Clearly, a more comprehensive understanding of the TLR7 signaling axis will contribute to its molecular targeting. TRIF related adaptor molecule (TRAM plays a vital role in TLR4 signaling by recruiting TRIF to TLR4, followed by endosomal trafficking of the complex and initiation of IRF3 dependent type I interferon production as well as NF-κB dependent pro-inflammatory cytokine production. Towards understanding the molecular mechanisms that regulate TLR7 functionality, we found that TRAM(-/- murine macrophages exhibited a transcriptional and translational impairment in TLR7 mediated RANTES, but not TNFα, production. Suppression of TRAM expression in human macrophages also resulted in an impairment in TLR7 mediated CCL5 and IFN-β, but not TNFα, gene induction. Furthermore, suppression of endogenous human TRAM expression in human macrophages significantly impaired RV16 induced CCL5 and IFNβ, but not TNFα gene induction. Additionally, TRAM-G2A dose-dependently inhibited TLR7 mediated activation of CCL5, IFNβ and IFNα reporter genes. TLR7-mediated phosphorylation and nuclear translocation of IRF3 was impaired in TRAM(-/- cells. Finally, co-immunoprecipitation studies indicated that TRAM physically interacts with MyD88 upon TLR7 stimulation, but not under basal conditions. Our results clearly demonstrate that TRAM plays a, hitherto unappreciated, role in TLR7 signaling through a novel signaling axis containing, but not limited to, MyD88, TRAM and IRF3 towards the activation of anti-viral immunity.
Meindl, George A; Ashman, Tia-Lynn
• For plant species that occur in heavy-metal-rich soil, floral metal accumulation may produce an "elemental filter" that reduces pollinator visitation rate and species richness and changes pollinator species composition relative to closely related species growing on normal soils. Consequently, metal hyperaccumulation may contribute to pollinator-mediated reproductive isolation between closely related plant species that differ in metal accumulation.• To test these ideas, we characterized plant-pollinator interactions in a sympatric pair of species that differ in metal accumulation (Streptanthus polygaloides, a nickel (Ni) hyperaccumulator, and S. tortuosus, a nonaccumulator). To test the elemental filter hypothesis, we presented arrays of S. polygaloides that were grown in either Ni-treated or control soils to insects at both S. polygaloides and S. tortuosus sites and recorded visitation.• Naturally occurring S. polygaloides hyperaccumulated Ni in anthers and accumulated Ni in nectar, while S. tortuosus did not. Floral visitation rates in natural populations were higher to S. tortuosus than S. polygaloides. In addition, while floral visitor richness was similar, few pollinator taxa were shared between the two plant species. Nickel-treatment of S. polygaloides reduced visits by bees, but only for arrays presented at S. tortuosus sites.• We show that the Ni hyperaccumulator S. polygaloides hosts a distinct floral visitor community, indicating that metal accumulation creates a filter for pollinators, similar to that documented for herbivores. Our study highlights a novel mechanism by which the abiotic environment can alter plant-pollinator interactions, and consequently plant reproduction and speciation. © 2015 Botanical Society of America, Inc.
Picone, Joanne M; Clery, Robin A; Watanabe, Naoharu; MacTavish, Hazel S; Turnbull, Colin G N
The control of rhythmic emission of floral volatiles emitted from Rosa damascena semperflorens cv. 'Quatre Saisons' throughout floral development under various light regimes was studied. 2-Phenylethanol was the major volatile emitted in addition to monoterpenols, oxidised monoterpenols, monoterpenes and aromatic compounds. All detected volatiles were emitted rhythmically, with maximum peaks coinciding 8-10 h into a 12-h photoperiod. For some compounds a secondary, nocturnal peak was apparent. The primary and secondary maxima both occurred at approximately 24-h intervals. Rhythms appeared to be regulated endogenously: rhythmic emission continued upon exposure to continuous light or continuous darkness, and a phase shift in emission was induced upon inversion of the photoperiod. Additionally, emission continued after flower excision. A similar profile of free volatiles was stored within the floral tissue, together with glycosidic forms of 2-phenylethanol (>99% beta-D-glucoside), benzyl alcohol, citronellol and geraniol. Regression analysis indicated a significant decrease in glycosylated 2-phenylethanol through the photoperiod. These results suggest that glycosylated volatiles stored within petals may be a source of rhythmically emitted volatiles.
Kellenberger, Roman T; Schlüter, Philipp M; Schiestl, Florian P
Plants have to fine-tune their signals to optimise the trade-off between herbivore deterrence and pollinator attraction. An important mechanism in mediating plant-insect interactions is the regulation of gene expression via DNA methylation. However, the effect of herbivore-induced DNA methylation changes on pollinator-relevant plant signalling has not been systematically investigated. Here, we assessed the impact of foliar herbivory on DNA methylation and floral traits in the model crop plant Brassica rapa. Methylation-sensitive amplified fragment length polymorphism (MSAP) analysis showed that leaf damage by the caterpillar Pieris brassicae was associated with genome-wide methylation changes in both leaves and flowers of B. rapa as well as a downturn in flower number, morphology and scent. A comparison to plants with jasmonic acid-induced defence showed similar demethylation patterns in leaves, but both the floral methylome and phenotype differed significantly from P. brassicae infested plants. Standardised genome-wide demethylation with 5-azacytidine in five different B. rapa full-sib groups further resulted in a genotype-specific downturn of floral morphology and scent, which significantly reduced the attractiveness of the plants to the pollinator bee Bombus terrestris. These results suggest that DNA methylation plays an important role in adjusting plant signalling in response to changing insect communities.
Gross, Karin; Sun, Mimi; Schiestl, Florian P
Geographically structured phenotypic selection can lead to adaptive divergence. However, in flowering plants, such divergent selection has rarely been shown, and selection on floral signals is generally little understood. In this study, we measured phenotypic selection on display size, floral color, and floral scent in four lowland and four mountain populations of the nectar-rewarding terrestrial orchid Gymnadenia odoratissima in two years. We also quantified population differences in these traits and pollinator community composition. Our results show positive selection on display size and positive, negative, or absence of selection on different scent compounds and floral color. Selection on the main scent compounds was consistently stronger in the lowlands than in the mountains, and lowland plants emitted higher amounts of most of these compounds. Pollinator community composition also differed between regions, suggesting different pollinators select for differences in floral volatiles. Overall, our study is the first to document consistent regional differences in selection on floral scent, suggesting this pattern of selection is one of the evolutionary forces contributing to regional divergence in floral chemical signaling.
Braynen, Janeen; Yang, Yan; Wei, Fang; Cao, Gangqiang; Shi, Gongyao; Tian, Baoming; Zhang, Xiaowei; Jia, Hao; Wei, Xiaochun; Wei, Zhenzhen
Polyploidy is a fundamental process in plant evolution. Understanding the polyploidy-associated effects on plant reproduction is essential for polyploid breeding program. In the present study, our cytological analysis firstly demonstrated that an overall course of meiosis was apparently distorted in the synthetic polyploid Brassica rapa in comparison with its diploid progenitor. To elucidate genetic basis of this irregular meiosis at a molecular level, the comparative RNA-seq analysis was further used to investigate differential genetic regulation of developing floral buds identified at meiosis between autotetraploid and diploid B. rapa. In total, compared to its diploid counterparts, among all 40,927 expressed genes revealed, 4,601 differentially expressed genes (DEGs) were identified in the floral buds of autotetraploid B. rapa, among which 288 DEGs annotated were involved in meiosis. Notably, DMC1 identified as one previously known meiosis-specific gene involved in inter-homologous chromosome dependent repair of DNA double stranded breaks (DSBs), was significantly down-regulated in autotetraploid B. rapa, which presumably contributed to abnormal progression during meiosis I. Although certain DEGs associated with RNA helicase, cell cycling, and somatic DNA repair were up-regulated after genome duplication, genes associated with meiotic DSB repair were significantly down-regulated. Furthermore, the expression of randomly selected DEGs by RNA-seq analysis was confirmed by quantitative real-time PCR analysis in both B. rapa and Arabidopsis thaliana. Our results firstly account for adverse effects of polyploidy on an entire course of meiosis at both cytological and transcriptomic levels, and allow for a comprehensive understanding of the uniformity and differences in the transcriptome of floral buds at meiosis between diploid and polyploid B. rapa as well.
Lee, M.J.; Crous, P.W.; Wingfield, M.J.
Eight pestalotioid fungi were isolated from the Restionaceae growing in the Cape Floral Kingdom of South Africa. Sarcostroma restionis, Truncatella megaspora, T. restionacearum and T. spadicea are newly described. New records include Pestalotiopsis matildae, Sarcostroma lomatiae, Truncatella betulae
Lee, S.; Crous, P.W.; Wingfield, M.J.
Eight pestalotioid fungi were isolated from the Restionaceae growing in the Cape Floral Kingdom of South Africa. Sarcostroma restionis, Truncatella megaspora, T. restionacearum and T. spadicea are newly described. New records include Pestalotiopsis matildae, Sarcostroma lomatiae, Truncatella betulae
Sedonia D Sipes
Full Text Available Floral scent is likely important to the pollination of parasitic plants, despite that it has not been well-studied. We studied the pollination ecology of the North American stem holoparasite Pilostyles thurberi (Apodanthaceae at two field sites in Texas. To identify effective pollinators, we collected floral visitors to P. thurberi flowers, observed their foraging behavior, and looked for P. thurberi pollen on their bodies. Augochloropsis metallica bees (Halictidae and eumenine potter wasps (Vespidae were pollinators. P. thurberi flowers are visually inconspicuous but produce a strong fruity fragrance. GC/MS analysis of whole floral extracts and dynamic headspace samples revealed the fragrance to be an unusually simple bouquet of raspberry ketone and several eugenols. Comparison of scent profiles to those from uninfected host plants (Dalea formosa allowed putative separation of parasite and host volatiles. This is the first report of the constituents of floral fragrance in Apodanthaceae.
Full Text Available ll LA. FEBS Lett. 2005 Jun 13;579(15):3330-5. Epub 2005 Apr 26. (.png) (.svg) (.html) (.csml) Show Adaptor u...05 Jun 13;579(15):3330-5. Epub 2005 Apr 26. Pathway - PNG File (.png) SVG File (.svg) HTML File (.html) CSML
Meijer, A.H.; Krens, SF Gabby; Rodriguez, IA Medina; He, S; Bitter, W.; Snaar-Jagalska, B Ewa; Spaink, H.P.
The zebrafish genomic sequence database was analysed for the presence of genes encoding members of the Toll-like receptors (TLR) and interleukin receptors (IL-R) and associated adaptor proteins containing a TIR domain. The resulting predictions show the presence of one or more counterparts for the
Azpeitia, Eugenio; Davila-Velderrain, José; Villarreal, Carlos; Alvarez-Buylla, Elena R
Understanding how genotypes map unto phenotypes implies an integrative understanding of the processes regulating cell differentiation and morphogenesis, which comprise development. Such a task requires the use of theoretical and computational approaches to integrate and follow the concerted action of multiple genetic and nongenetic components that hold highly nonlinear interactions. Gene regulatory network (GRN) models have been proposed to approach such task. GRN models have become very useful to understand how such types of interactions restrict the multi-gene expression patterns that characterize different cell-fates. More recently, such temporal single-cell models have been extended to recover the temporal and spatial components of morphogenesis. Since the complete genomic GRN is still unknown and intractable for any organism, and some clear developmental modules have been identified, we focus here on the analysis of well-curated and experimentally grounded small GRN modules. One of the first experimentally grounded GRN that was proposed and validated corresponds to the regulatory module involved in floral organ determination. In this chapter we use this GRN as an example of the methodologies involved in: (1) formalizing and integrating molecular genetic data into the logical functions (Boolean functions) that rule gene interactions and dynamics in a Boolean GRN; (2) the algorithms and computational approaches used to recover the steady-states that correspond to each cell type, as well as the set of initial GRN configurations that lead to each one of such states (i.e., basins of attraction); (3) the approaches used to validate a GRN model using wild type and mutant or overexpression data, or to test the robustness of the GRN being proposed; (4) some of the methods that have been used to incorporate random fluctuations in the GRN Boolean functions and enable stochastic GRN models to address the temporal sequence with which gene configurations and cell fates are
Since the first human tucked a flower in their hair, blooms have been a part of human adornment. Each epoch saw new interpretations of the floral in jewellery. The Romans had their ivy circlets, the Tudors long necklaces of clusters of tiny blossoms, the Victorians their detailed panoply of symbolic blooms, Art Nouveau its sinuous floral forms and twentieth-century costume pieces sprays of foliage and flowers. Despite this, the contemporary studio jewellery movement for many years rejected t...
Andersson, Susanna; Dobson, Heidi E M
Floral color has been shown to influence flower selection by butterflies, but few studies have investigated the role of floral scent. In this study, adults of Heliconius melpomene L. (Lepidoptera: Nymphalidae: Heliconiinae) were tested in two-choice bioassays to investigate their ability to distinguish floral scent of the butterfly pollinated plant Lantana camara L. (Verbenaceae) from other plant scents. The relative importance of floral scent vs. color was also studied. Butterfly foraging behavior was measured as probing with proboscis. This probing, on floral models varying in scent and color, was timed. When given a choice of floral and vegetative scents of L. camara, newly emerged butterflies preferred floral scent, indicating an innate response to floral scents. When butterflies were conditioned to L. camara floral scent by offering the scent with yellow color and sugar water, yellow color elicited stronger feeding responses than did the floral scent. However, the floral scent of L. camara was preferred to that of the novel species Philadelphus coronarius L. (Hydrangiaceae). The floral scent of L. camara was dominated by tepenoid compounds, while that of P. coronarius by fatty acid derivatives, thus demonstrating totally different compositions. It is concluded that, while H. melpomene butterflies often use visual floral traits when selecting which flowers to visit, floral scents elicit behavioral responses that initiate and maintain foraging on flowers.
Engelhorn, Julia; Moreau, Fanny; Fletcher, Jennifer C; Carles, Cristel C
The morphological variability of the flower in angiosperms, combined with its relatively simple structure, makes it an excellent model to study cell specification and the establishment of morphogenetic patterns. Flowers are the products of floral meristems, which are determinate structures that generate four different types of floral organs before terminating. The precise organization of the flower in whorls, each defined by the identity and number of organs it contains, is controlled by a multi-layered network involving numerous transcriptional regulators. In particular, the AGAMOUS (AG) MADS domain-containing transcription factor plays a major role in controlling floral determinacy in Arabidopsis thaliana in addition to specifying reproductive organ identity. This study aims to characterize the genetic interactions between the ULTRAPETALA1 (ULT1) and LEAFY (LFY) transcriptional regulators during flower morphogenesis, with a focus on AG regulation. Genetic and molecular approaches were used to address the question of redundancy and reciprocal interdependency for the establishment of flower meristem initiation, identity and termination. In particular, the effects of loss of both ULT1 and LFY function were determined by analysing flower developmental phenotypes of double-mutant plants. The dependency of each factor on the other for activating developmental genes was also investigated in gain-of-function experiments. The ULT1 and LFY pathways, while both activating AG expression in the centre of the flower meristem, functioned independently in floral meristem determinacy. Ectopic transcriptional activation by ULT1 of AG and AP3, another gene encoding a MADS domain-containing flower architect, did not depend on LFY function. Similarly, LFY did not require ULT1 function to ectopically determine floral fate. The results indicate that the ULT1 and LFY pathways act separately in regulating identity and determinacy at the floral meristem. In particular, they independently
Mario Augusto Gonçalves Jardim
Full Text Available Neste artigo são apresentadas informações sobre a biologia floral de Virola surinamensis (Rol. Warb. (Myristicaceae, espécie florestal dióica de relevante importância econômica na região amazônica. O estudo foi realizado em uma área de várzea próximo à bacia do igarapé Murutucum, lado direito do rio Guamá, localizada no Campus da Faculdade de Ciências Agrárias do Pará, na cidade de Belém, Estado do Pará, no período de janeiro a dezembro de 2001. Avaliou-se a biologia floral desde o aparecimento dos botões florais até a senescência das flores estaminadas, bem como a formação de frutos nas flores pistiladas. Testes bioquímicos foram aplicados para verificação de odor, pigmentos, osmóforos e receptividade do estigma. A observação no comportamento dos visitantes florais foi realizada durante o período diurno, registrando-se os horários de visitas, tempo de permanência na flor e freqüência; alguns indivíduos foram coletados com rede entomológica e identificados no Departamento de Zoologia do Museu Paraense Emílio Goeldi. A antese ocorreu entre 6 e 16 h nas flores estaminadas e entre 8 e 16 h nas flores pistiladas; a presença de odor foi constatada apenas nas flores estaminadas, enquanto os pigmentos e osmóforos foram encontrados em ambas as flores; o estigma mostrou-se receptivo no período entre 12 e 14 h. Os insetos da ordem diptera foram os visitantes mais freqüentes nas flores estaminadas e pistiladas e as espécies Copestylum sp. e Erystalys sp., as responsáveis pela polinização.Information was obtained on the floral biology of Virola surinamensis (Rol. Warb. (Myristicaceae, a dioecious arboreal species of great importance for the Amazon region economy. The study was carried out in the floodplain area near the Murucutu stream, on the right side of the Guamá River, at the Universidade Federal Rural da Amazônia-UFRA, Belém-Pará , from January to December 2001. Floral biology was assessed from
Pawełkowicz, Magdalena Ewa; Skarzyńska, Agnieszka; Cebula, Justyna; Hincha, Dirck; ZiÄ bska, Karolina; PlÄ der, Wojciech; Przybecki, Zbigniew
The application of genomic approaches may serve as an initial step in understanding the complexity of biochemical network and cellular processes responsible for regulation and execution of many developmental tasks. The molecular mechanism of sex expression in cucumber is still not elucidated. A study of differential expression was conducted to identify genes involved in sex determination and floral organ morphogenesis. Herein, we present generation of expression sequence tags (EST) obtained by differential hybridization (DH) and subtraction technique (cDNA-DSC) and their characteristic features such as molecular function, involvement in biology processes, expression and mapping position on the genome.
MARISOL AMAYA MÁRQUEZ
Full Text Available Los polinizadores altamente especializados en su dieta, no hacen escogencias florales, ellos visitan un recurso específico siguiendo el dictado de la información almacenada en sus genes. En contraste, para la abeja social Apis mellifera una escogencia floral implica, la toma de una decisión, usualmente con criterio económico, basada en información aprendida y almacenada en alguna forma de memoria. Aunque existen numerosos estudios y modelos sobre la escogencia floral en abejas, la gran mayoría de éstos, han derivado sus conclusiones a partir de condiciones temporalmente fijas de la interacción. Muy pocos estudios han abordado la dinámica propia del contexto ecológico, en el cual el mercado floral de las abejas cambia con las estaciones del año y con los patrones diarios de antesis floral. Este cambio en la disponibilidad de especies florales enfrenta a los polinizadores, a realizar escogencias secuenciales acerca del alimento a explotar. En este trabajo abordo el tema del forrajeo secuencial en parches florales heterospecíficos, enfocándome en el uso que la abeja melífera hace de la información previamente aprendida en un contexto, cuando se enfrenta a la explotación de alimento en un contexto ecológicamente diferente. He realizado experimentos sobre escogencia floral simulando las condiciones de cambio del paisaje floral, exponiendo abejas individuales de A. mellifera a decidir sobre cuales especies forrajear en cada parche. Los resultados indican que la abeja invierte en procesos de aprendizaje en un muestreo inicial, pero una vez almacenada la información, utiliza una pieza de la información previamente aprendida (color para explotar parches florales heteroespecíficos siguiendo una imagen de búsqueda de color. En esta revisión discuto situaciones biológicas de la interacción planta-abeja, las cuales apoyan la idea que en la naturaleza el uso de imágenes de búsqueda de color por parte de abejas sociales puede ser m
Full Text Available Abstract Background We have further characterized floral organ-localized gene expression in the inflorescence of Arabidopsis thaliana by comparison of massively parallel signature sequencing (MPSS data. Six libraries of RNA sequence tags from immature inflorescence tissues were constructed and matched to their respective loci in the annotated Arabidopsis genome. These signature libraries survey the floral transcriptome of wild-type tissue as well as the floral homeotic mutants, apetala1, apetala3, agamous, a superman/apetala1 double mutant, and differentiated ovules dissected from the gynoecia of wild-type inflorescences. Comparing and contrasting these MPSS floral expression libraries enabled demarcation of transcripts enriched in the petals, stamens, stigma-style, gynoecia, and those with predicted enrichment within the sepal/sepal-petals, petal-stamens, or gynoecia-stamens. Results By comparison of expression libraries, a total of 572 genes were found to have organ-enriched expression within the inflorescence. The bulk of characterized organ-enriched transcript diversity was noted in the gynoecia and stamens, whereas fewer genes demonstrated sepal or petal-localized expression. Validation of the computational analyses was performed by comparison with previously published expression data, in situ hybridizations, promoter-reporter fusions, and reverse transcription PCR. A number of well-characterized genes were accurately delineated within our system of transcript filtration. Moreover, empirical validations confirm MPSS predictions for several genes with previously uncharacterized expression patterns. Conclusion This extensive MPSS analysis confirms and supplements prior microarray floral expression studies and illustrates the utility of sequence survey-based expression analysis in functional genomics. Spatial floral expression data accrued by MPSS and similar methods will be advantageous in the elucidation of more comprehensive genetic
López-González, Leticia; Mouriz, Alfonso; Narro-Diego, Laura; Bustos, Regla; Martínez-Zapater, José Miguel; Jarillo, Jose A; Piñeiro, Manuel
The interplay among histone modifications modulates the expression of master regulatory genes in development. Chromatin effector proteins bind histone modifications and translate the epigenetic status into gene expression patterns that control development. Here, we show that two Arabidopsis thaliana paralogs encoding plant-specific proteins with a plant homeodomain (PHD) motif, SHORT LIFE (SHL) and EARLY BOLTING IN SHORT DAYS (EBS), function in the chromatin-mediated repression of floral initiation and play independent roles in the control of genes regulating flowering. Previous results showed that repression of the floral integrator FLOWERING LOCUS T (FT) requires EBS. We establish that SHL is necessary to negatively regulate the expression of SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1), another floral integrator. SHL and EBS recognize di- and trimethylated histone H3 at lysine 4 and bind regulatory regions of SOC1 and FT, respectively. These PHD proteins maintain an inactive chromatin conformation in SOC1 and FT by preventing high levels of H3 acetylation, bind HISTONE DEACETYLASE6, and play a central role in regulating flowering time. SHL and EBS are widely conserved in plants but are absent in other eukaryotes, suggesting that the regulatory module mediated by these proteins could represent a distinct mechanism for gene expression control in plants. © 2014 American Society of Plant Biologists. All rights reserved.
López-González, Leticia; Mouriz, Alfonso; Narro-Diego, Laura; Bustos, Regla; Martínez-Zapater, José Miguel; Jarillo, Jose A.; Piñeiro, Manuel
The interplay among histone modifications modulates the expression of master regulatory genes in development. Chromatin effector proteins bind histone modifications and translate the epigenetic status into gene expression patterns that control development. Here, we show that two Arabidopsis thaliana paralogs encoding plant-specific proteins with a plant homeodomain (PHD) motif, SHORT LIFE (SHL) and EARLY BOLTING IN SHORT DAYS (EBS), function in the chromatin-mediated repression of floral initiation and play independent roles in the control of genes regulating flowering. Previous results showed that repression of the floral integrator FLOWERING LOCUS T (FT) requires EBS. We establish that SHL is necessary to negatively regulate the expression of SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1), another floral integrator. SHL and EBS recognize di- and trimethylated histone H3 at lysine 4 and bind regulatory regions of SOC1 and FT, respectively. These PHD proteins maintain an inactive chromatin conformation in SOC1 and FT by preventing high levels of H3 acetylation, bind HISTONE DEACETYLASE6, and play a central role in regulating flowering time. SHL and EBS are widely conserved in plants but are absent in other eukaryotes, suggesting that the regulatory module mediated by these proteins could represent a distinct mechanism for gene expression control in plants. PMID:25281686
Full Text Available RESUMEN
Los polinizadores altamente especializados en su dieta, no hacen escogencias florales, ellos visitan un recurso específico siguiendo el dictado de la información almacenada en sus genes. En contraste, para la abeja social Apis mellifera una escogencia floral implica, la toma de una decisión, usualmente con criterio económico, basada en información aprendida y almacenada en alguna forma de memoria. Aunque existen numerosos estudios y modelos sobre la escogencia floral en abejas, la gran mayoría de éstos, han derivado sus conclusiones a partir de condiciones temporalmente fijas de la interacción. Muy pocos estudios han abordado la dinámica propia del contexto ecológico, en el cual el mercado floral de las abejas cambia con las estaciones del año y con los patrones diarios de antesis floral. Este cambio en la disponibilidad de especies florales enfrenta a los polinizadores, a realizar escogencias secuenciales acerca del alimento a explotar. En este trabajo abordo el tema del forrajeo secuencial en parches florales heterospecíficos, enfocándome en el uso que la abeja melífera hace de la información previamente aprendida en un contexto, cuando se enfrenta a la explotación de alimento en un contexto ecológicamente diferente. He realizado experimentos sobre escogencia floral simulando las condiciones de cambio del paisaje floral, exponiendo abejas individuales de A. mellifera a decidir sobre cuales especies forrajear en cada parche. Los resultados indican que la abeja invierte en procesos de aprendizaje en un muestreo inicial, pero una vez almacenada la información, utiliza una pieza de la información previamente aprendida (color para explotar parches florales heteroespecíficos siguiendo una imagen de búsqueda de color. En esta revisión discuto situaciones biológicas de la interacción planta-abeja, las cuales apoyan la idea que en la naturaleza el uso de imágenes de búsqueda de color por parte de abejas
Full Text Available RESUMEN Los polinizadores altamente especializados en su dieta, no hacen escogencias florales, ellos visitan un recurso específico siguiendo el dictado de la información almacenada en sus genes. En contraste, para la abeja social Apis mellifera una escogencia floral implica, la toma de una decisión, usualmente con criterio económico, basada en información aprendida y almacenada en alguna forma de memoria. Aunque existen numerosos estudios y modelos sobre la escogencia floral en abejas, la gran mayoría de éstos, han derivado sus conclusiones a partir de condiciones temporalmente fijas de la interacción. Muy pocos estudios han abordado la dinámica propia del contexto ecológico, en el cual el mercado floral de las abejas cambia con las estaciones del año y con los patrones diarios de antesis floral. Este cambio en la disponibilidad de especies florales enfrenta a los polinizadores, a realizar escogencias secuenciales acerca del alimento a explotar. En este trabajo abordo el tema del forrajeo secuencial en parches florales heterospecíficos, enfocándome en el uso que la abeja melífera hace de la información previamente aprendida en un contexto, cuando se enfrenta a la explotación de alimento en un contexto ecológicamente diferente. He realizado experimentos sobre escogencia floral simulando las condiciones de cambio del paisaje floral, exponiendo abejas individuales de A. mellifera a decidir sobre cuales especies forrajear en cada parche. Los resultados indican que la abeja invierte en procesos de aprendizaje en un muestreo inicial, pero una vez almacenada la información, utiliza una pieza de la información previamente aprendida (color para explotar parches florales heteroespecíficos siguiendo una imagen de búsqueda de color. En esta revisión discuto situaciones biológicas de la interacción planta-abeja, las cuales apoyan la idea que en la naturaleza el uso de imágenes de búsqueda de color por parte de abejas sociales puede
Lim Chee Liew
Full Text Available Epigenetics has been recognised to play vital roles in many plant developmental processes, including floral initiation through the epigenetic regulation of gene expression. The histone modifying proteins that mediate these modifications involve the SET domain-containing histone methyltransferases, JmjC domain-containing demethylase, acetylases and deacetylases. In addition, RNA interference (RNAi-associated genes are also involved in epigenetic regulation via RNA-directed DNA methylation and post-transcriptional gene silencing. Soybean, a major crop legume, requires a short day to induce flowering. How histone modifications regulate the plant response to external cues that initiate flowering is still largely unknown. Here, we used RNA-seq to address the dynamics of transcripts that are potentially involved in the epigenetic programming and RNAi mediated gene silencing during the floral initiation of soybean. Soybean is a paleopolyploid that has been subjected to at least two rounds of whole genome duplication events. We report that the expanded genomic repertoire of histone modifiers and RNA silencing genes in soybean includes 14 histone acetyltransferases, 24 histone deacetylases, 47 histone methyltransferases, 15 protein arginine methyltransferases, 24 JmjC domain-containing demethylases and 47 RNAi-associated genes. To investigate the role of these histone modifiers and RNA silencing genes during floral initiation, we compared the transcriptional dynamics of the leaf and shoot apical meristem at different time points after a short-day treatment. Our data reveal that the extensive activation of genes that are usually involved in the epigenetic programming and RNAi gene silencing in the soybean shoot apical meristem are reprogrammed for floral development following an exposure to inductive conditions.
Kelly, Bernard T; Graham, Stephen C; Liska, Nicole; Dannhauser, Philip N; Höning, Stefan; Ungewickell, Ernst J; Owen, David J
Clathrin-mediated endocytosis (CME) is vital for the internalization of most cell-surface proteins. In CME, plasma membrane-binding clathrin adaptors recruit and polymerize clathrin to form clathrin-coated pits into which cargo is sorted. Assembly polypeptide 2 (AP2) is the most abundant adaptor and is pivotal to CME. Here, we determined a structure of AP2 that includes the clathrin-binding β2 hinge and developed an AP2-dependent budding assay. Our findings suggest that an autoinhibitory mechanism prevents clathrin recruitment by cytosolic AP2. A large-scale conformational change driven by the plasma membrane phosphoinositide phosphatidylinositol 4,5-bisphosphate and cargo relieves this autoinhibition, triggering clathrin recruitment and hence clathrin-coated bud formation. This molecular switching mechanism can couple AP2's membrane recruitment to its key functions of cargo and clathrin binding. Copyright © 2014, American Association for the Advancement of Science.
Tin, M M Y; Rheindt, F E; Cros, E; Mikheyev, A S
RAD-tag is a powerful tool for high-throughput genotyping. It relies on PCR amplification of the starting material, following enzymatic digestion and sequencing adaptor ligation. Amplification introduces duplicate reads into the data, which arise from the same template molecule and are statistically nonindependent, potentially introducing errors into genotype calling. In shotgun sequencing, data duplicates are removed by filtering reads starting at the same position in the alignment. However, restriction enzymes target specific locations within the genome, causing reads to start in the same place, and making it difficult to estimate the extent of PCR duplication. Here, we introduce a slight change to the Illumina sequencing adaptor chemistry, appending a unique four-base tag to the first index read, which allows duplicate discrimination in aligned data. This approach was validated on the Illumina MiSeq platform, using double-digest libraries of ants (Wasmannia auropunctata) and yeast (Saccharomyces cerevisiae) with known genotypes, producing modest though statistically significant gains in the odds of calling a genotype accurately. More importantly, removing duplicates also corrected for strong sample-to-sample variability of genotype calling accuracy seen in the ant samples. For libraries prepared from low-input degraded museum bird samples (Mixornis gularis), which had low complexity, having been generated from relatively few starting molecules, adaptor tags show that virtually all of the genotypes were called with inflated confidence as a result of PCR duplicates. Quantification of library complexity by adaptor tagging does not significantly increase the difficulty of the overall workflow or its cost, but corrects for differences in quality between samples and permits analysis of low-input material. © 2014 John Wiley & Sons Ltd.
Alario, Anthony F; Pirie, Christopher G
The purpose of this study was to describe fluorescein gonioangiography (FGA) of the normal canine eye using a digital single lens reflex (dSLR) camera adaptor. Dogs were anesthetized using intravenous propofol. Imaging was performed using a Lovac Barkan goniolens, dSLR camera, dSLR camera adaptor, camera lens, and accessory flash. Twelve dogs with a mean age of 2.0 +/- 0.8 years were imaged. No characteristic angiographic phases were observed. Leakage from the peri-limbal capillary network was a common finding and occurred 7.7 +/- 2.2 s post injection in 9 (75%) dogs. In 3 (25%) dogs, filling of the circumferential ciliary artery was observed 10.3 +/- 2.8 s post injection. Dye leakage within the iris base and into the aqueous humor was demonstrated in 4 (33%) and 6 dogs (50%) respectively. No adverse events were noted. This study demonstrates FGA findings in normal canine eyes using a cost effective dSLR camera adaptor. Copyright © 2015 Elsevier Ltd. All rights reserved.
Daud, N; Taha, R M
Intact immature flower buds of African violet (Saintpaulia ionantha H. Wendl.) were used as explant sources for in vitro studies. The effect of exogenous hormones, NAA and BAP on the indirect organogenesis of this species was observed. Callus was formed on the cut end (base) of pedicels of floral buds where they were in contact with the medium. When maintained on the same medium, callus was differentiated into adventitious shoots after 10 weeks in culture. MS media supplemented with 2.0 mg L(-1) NAA and 1.0 mg L(-1) BAP gave the highest number of sterile or vegetative floral buds from the surface of callus of the explants, but these buds failed to develop further. The floral buds were expanded as abnormal flowers. The floral structures were smaller in size compared to intact flowers. Petals (corolla) were white to purple in colour but did not form any reproductive organs, i.e., stamens or pistils. All sterile or vegetative floral buds and abnormal flowers survived for 3 months in culture but failed to reach anthesis.
Xu, Fengxia; Ronse De Craene, Louis
Annonaceae are one of the largest families of Magnoliales. This study investigates the comparative floral development of 15 species to understand the basis for evolutionary changes in the perianth, androecium and carpels and to provide additional characters for phylogenetic investigation. Floral ontogeny of 15 species from 12 genera is examined and described using scanning electron microscopy. Initiation of the three perianth whorls is either helical or unidirectional. Merism is mostly trimerous, occasionally tetramerous and the members of the inner perianth whorl may be missing or are in double position. The androecium and the gynoecium were found to be variable in organ numbers (from highly polymerous to a fixed number, six in the androecium and one or two in the gynoecium). Initiation of the androecium starts invariably with three pairs of stamen primordia along the sides of the hexagonal floral apex. Although inner staminodes were not observed, they were reported in other genera and other families of Magnoliales, except Magnoliaceae and Myristicaceae. Initiation of further organs is centripetal. Androecia with relatively low stamen numbers have a whorled phyllotaxis throughout, while phyllotaxis becomes irregular with higher stamen numbers. The limits between stamens and carpels are unstable and carpels continue the sequence of stamens with a similar variability. It was found that merism of flowers is often variable in some species with fluctuations between trimery and tetramery. Doubling of inner perianth parts is caused by (unequal) splitting of primordia, contrary to the androecium, and is independent of changes of merism. Derived features, such as a variable merism, absence of the inner perianth and inner staminodes, fixed numbers of stamen and carpels, and capitate or elongate styles are distributed in different clades and evolved independently. The evolution of the androecium is discussed in the context of basal angiosperms: paired outer stamens are the
Effmert,U.; Saschenbrecker, S.; Ross, J.; Negre, F.; Fraser, C.; Noel, J.; Dudareva, N.; Piechulla, B.
Benzenoid carboxyl methyltransferases synthesize methyl esters (e.g., methyl benzoate and methyl salicylate), which are constituents of aromas and scents of many plant species and play important roles in plant communication with the surrounding environment. Within the past five years, eleven such carboxyl methyltransferases were isolated and most of them were comprehensively investigated at the biochemical, molecular and structural level. Two types of enzymes can be distinguished according to their substrate preferences: the SAMT-type enzymes isolated from Clarkia breweri, Stephanotis floribunda, Antirrhinum majus, Hoya carnosa, and Petunia hybrida, which have a higher catalytic efficiency and preference for salicylic acid, while BAMT-type enzymes from A. majus, Arabidopsis thaliana, Arabidopsis lyrata, and Nicotiana suaveolens prefer benzoic acid. The elucidation of C. breweri SAMT's three-dimensional structure allowed a detailed modelling of the active sites of the carboxyl methyltransferases and revealed that the SAM binding pocket is highly conserved among these enzymes while the methyl acceptor binding site exhibits some variability, allowing a classification into SAMT-type and BAMT-type enzymes. The analysis of expression patterns coupled with biochemical characterization showed that these carboxyl methyltransferases are involved either in floral scent biosynthesis or in plant defense responses. While the latter can be induced by biotic or abiotic stress, the genes responsible for floral scent synthesis exhibit developmental and rhythmic expression pattern. The nature of the product and efficiency of its formation in plants depend on the availability of substrates, the catalytic efficiency of the enzyme toward benzoic acid and/or salicylic acid, and the transcriptional, translational, and post-translational regulation at the enzyme level. The biochemical properties of benzenoid carboxyl methyltransferases suggest that the genes involved in plant defenses
Kelly, Bernard T; Graham, Stephen C; Owen, David J
Selenomethionine incorporation is a powerful technique for assigning sequence to regions of electron density at low resolution. Genetic introduction of methionine point mutations and the subsequent preparation and crystallization of selenomethionyl derivatives permits unambiguous sequence assignment by enabling the placement of the anomalous scatterers (Se atoms) thus introduced. Here, the use of this approach in the assignment of sequence in a part of the AP2 clathrin adaptor complex that is responsible for clathrin binding is described. AP2 plays a pivotal role in clathrin-mediated endocytosis, a tightly regulated process in which cell-surface transmembrane proteins are internalized from the plasma membrane by incorporation into lipid-enclosed transport vesicles. AP2 binds cargo destined for internalization and recruits clathrin, a large trimeric protein that helps to deform the membrane to produce the transport vesicle. By selenomethionine labelling of point mutants, it was shown that the clathrin-binding site is buried within a deep cleft of the AP2 complex. A membrane-stimulated conformational change in AP2 releases the clathrin-binding site from autoinhibition, thereby linking clathrin recruitment to membrane localization.
Tian, Yuan; Chang, Jerry C; Fan, Emily Y; Flajolet, Marc; Greengard, Paul
The hallmarks of Alzheimer's disease (AD) are the aggregates of amyloid-β (Aβ) peptides and tau protein. Autophagy is a major cellular pathway leading to the removal of aggregated proteins. We have reported recently that autophagy was responsible for amyloid precursor protein cleaved C-terminal fragment (APP-CTF) degradation and amyloid β clearance in an Atg5-dependent manner. Here we aimed to elucidate the molecular mechanism by which autophagy mediates the degradation of APP-CTF and the clearance of amyloid β. Through affinity purification followed by mass spectrum analysis, we identified adaptor protein (AP) 2 together with phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (PICALM) as binding proteins of microtubule-associated protein 1 light chain 3 (LC3). Further analysis showed that AP2 regulated the cellular levels of APP-CTF. Knockdown of AP2 reduced autophagy-mediated APP-CTF degradation. Immunoprecipitation and live imaging analysis demonstrated that AP2 and PICALM cross-link LC3 with APP-CTF. These data suggest that the AP-2/PICALM complex functions as an autophagic cargo receptor for the recognition and shipment of APP-CTF from the endocytic pathway to the LC3-marked autophagic degradation pathway. This molecular mechanism linking AP2/PICALM and AD is consistent with genetic evidence indicating a role for PICALM as a risk factor for AD.
Xue, Jingqi; Li, Yunhui; Tan, Hui; Yang, Feng; Ma, Nan; Gao, Junping
Ethylene production, as well as the expression of ethylene biosynthetic (Rh-ACS1-4 and Rh-ACO1) and receptor (Rh-ETR1-5) genes, was determined in five different floral tissues (sepals, petals, stamens, gynoecia, and receptacles) of cut rose (Rosa hybrida cv. Samantha upon treatment with ethylene or the ethylene inhibitor 1-methylcyclopropene (1-MCP). Ethylene-enhanced ethylene production occurred only in gynoecia, petals, and receptacles, with gynoecia showing the greatest enhancement in the early stage of ethylene treatment. However, 1-MCP did not suppress ethylene production in these three tissues. In sepals, ethylene production was highly decreased by ethylene treatment, and increased dramatically by 1-MCP. Ethylene production in stamens remained unchanged after ethylene or 1-MCP treatment. Induction of certain ethylene biosynthetic genes by ethylene in different floral tissues was positively correlated with the ethylene production, and this induction was also not suppressed by 1-MCP. The expression of Rh-ACS2 and Rh-ACS3 was quickly induced by ethylene in gynoecia, but neither Rh-ACS1 nor Rh-ACS4 was induced by ethylene in any of the five tissues. In addition, Rh-ACO1 was induced by ethylene in all floral tissues except sepals. The induced expression of ethylene receptor genes by ethylene was much faster in gynoecia than in petals, and the expression of Rh-ETR3 was strongly suppressed by 1-MCP in all floral tissues. These results indicate that ethylene biosynthesis in gynoecia is regulated developmentally, rather than autocatalytically. The response of rose flowers to ethylene occurs initially in gynoecia, and ethylene may regulate flower opening mainly through the Rh-ETR3 gene in gynoecia.
Full Text Available El propósito de este trabajo fue caracterizar las fases fenológicas florales y determinar los visitantes florales en una población natural de Drimys granadensis (nombre común: canelo; Winteraceae ubicada en Altos de Yerbabuena ( 2.850 m , cerros orientales de la Sabana de Bogotá, (Colombia. El desarrollo fenológico floral duró 9,5 días cuando la floración ocurrió en época soleada, 12,5 días en época lluviosa y 16 días cuando se excluyeron a los visitantes florales mediante embolsado. Se realizaron observaciones del recurso utilizado, fase fenólogica de la flor visitada y cargas polínicas en los visitante florales, los cuales correspondieron a seis órdenes, 21 familias y 29 morfoespecies de insectos. Cuatro especies de coleópteros y dos de dípteros fueron considerados posibles polinizadores por su abundancia y carga de polen. Los resultados obtenidos se discuten en relación con aquellos reportados en otras especies del género Drimys y de la familia Winteraceae.The purpose of this research was to characterize the flowering phenological phases and to determine the flower visitors in a natural population of Drimys granadensis (common name: canelo; Winteraceae in Altos de Yerbabuena, eastern mountains of Sabana de Bogotá ( Colombia . Floral phenology development lasted 9.5 days when flowering occurred under sunny conditions, 12.5 days under rainy conditions and 16 days when flower visitors were excluded using cloth bags. It was done observations related with the resources used, the phenological phases of visited flowers and the pollen load on the flower visitors. Visitors corresponded with 29 morphospecies, 6 orders y 21 families of insects. Four species of coleoptera and two species of diptera were considered as possible pollinators taking in account abundance and pollen load. The results are analyzed in relation with those reported for other species in the genus Drimys and in the family Winteraceae.
Julieta Grajales-Conesa; Virginia Meléndez-Ramírez; Leopoldo Cruz-López
Las plantas emplean diversas señales visuales y olfativas con la finalidad de atraer a los polinizadores que en su mayoría son insectos. Algunas plantas han desarrollado mecanismos, basándose en mensajes olfativos que los hacen únicos para sus polinizadores específicos. Estos mecanismos, así como las variaciones intra- e interespecíficas en el perfil de los aromas florales han evolucionado para determinadas especies. Los aromas florales son un conjunto de compuestos volátiles orgánicos y para...
MARISOL AMAYA MÁRQUEZ
Full Text Available Los polinizadores altamente especializados en su dieta, no hacen escogencias florales, ellos visitan un recurso específico siguiendo el dictado de la información almacenada en sus genes. En contraste, para la abeja social Apis mellifera una escogencia floral implica, la toma de una decisión, usualmente con criterio económico, basada en información aprendida y almacenada en alguna forma de memoria. Aunque existen numerosos estudios y modelos sobre la escogencia floral en abejas, la gran mayoría de éstos, han derivado sus conclusiones a partir de condiciones temporalmente fijas de la interacción. Muy pocos estudios han abordado la dinámica propia del contexto ecológico, en el cual el mercado floral de las abejas cambia con las estaciones del año y con los patrones diarios de antesis floral. Este cambio en la disponibilidad de especies florales enfrenta a los polinizadores, a realizar escogencias secuenciales acerca del alimento a explotar. En este trabajo abordo el tema del forrajeo secuencial en parches florales heterospecíficos, enfocándome en el uso que la abeja melífera hace de la información previamente aprendida en un contexto, cuando se enfrenta a la explotación de alimento en un contexto ecológicamente diferente. He realizado experimentos sobre escogencia floral simulando las condiciones de cambio del paisaje floral, exponiendo abejas individuales de A. mellifera a decidir sobre cuales especies forrajear en cada parche. Los resultados indican que la abeja invierte en procesos de aprendizaje en un muestreo inicial, pero una vez almacenada la información, utiliza una pieza de la información previamente aprendida (color para explotar parches florales heteroespecíficos siguiendo una imagen de búsqueda de color. En esta revisión discuto situaciones biológicas de la interacción planta-abeja, las cuales apoyan la idea que en la naturaleza el uso de imágenes de búsqueda de color por parte de abejas sociales puede ser m
Full Text Available MyD88, a Toll/interleukin-1 receptor homology (TIR domain-containing adaptor protein, mediates signals from the Toll-like receptors (TLR or IL-1/IL-18 receptors to downstream kinases. In MyD88-dependent TLR4 signaling, the function of MyD88 is enhanced by another TIR domain-containing adaptor, Mal/TIRAP, which brings MyD88 to the plasma membrane and promotes its interaction with the cytosolic region of TLR4. Hence, Mal is recognized as the "sorting adaptor" for MyD88. In this study, a direct interaction between MyD88-TIR and another membrane-sorting adaptor, TRAM/TICAM-2, was demonstrated in vitro. Cell-based assays including RNA interference experiments and TRAM deficient mice revealed that the interplay between MyD88 and TRAM in cells is important in mediating IL-18 signal transduction. Live cell imaging further demonstrated the co-localized accumulation of MyD88 and TRAM in the membrane regions in HEK293 cells. These findings suggest that TRAM serves as the sorting adaptor for MyD88 in IL-18 signaling, which then facilitates the signal transduction. The binding sites for TRAM are located in the TIR domain of MyD88 and actually overlap with the binding sites for Mal. MyD88, the multifunctional signaling adaptor that works together with most of the TLR members and with the IL-1/IL-18 receptors, can interact with two distinct sorting adaptors, TRAM and Mal, in a conserved manner in a distinct context.
Full Text Available U1 Adaptor is a recently discovered oligonucleotide-based gene-silencing technology with a unique mechanism of action that targets nuclear pre-mRNA processing. U1 Adaptors have two distinct functional domains, both of which must be present on the same oligonucleotide to exert their gene-silencing function. Here, we present the first in vivo use of U1 Adaptors by targeting two different human genes implicated in melanomagenesis, B-cell lymphoma 2 (BCL2 and metabotropic glutamate receptor 1 (GRM1, in a human melanoma cell xenograft mouse model system. Using a newly developed dendrimer delivery system, anti-BCL2 U1 Adaptors were very potent and suppressed tumor growth at doses as low as 34 µg/kg with twice weekly intravenous (iv administration. Anti-GRM1 U1 Adaptors suppressed tumor xenograft growth with similar potency. Mechanism of action was demonstrated by showing target gene suppression in tumors and by observing that negative control U1 Adaptors with just one functional domain show no tumor suppression activity. The anti-BCL2 and anti-GRM1 treatments were equally effective against cell lines harboring either wild-type or a mutant V600E B-RAF allele, the most common mutation in melanoma. Treatment of normal immune-competent mice (C57BL6 indicated no organ toxicity or immune stimulation. These proof-of-concept studies represent an in-depth (over 800 mice in ~108 treatment groups validation that U1 Adaptors are a highly potent gene-silencing therapeutic and open the way for their further development to treat other human diseases.
This paper reports on a molecular analysis study conducted on Date palm flowers from the Deglet Nour cultivar to investigate putative genetic variability related to the in vitro floral hermaphrodism induction. Natural male and female as well as hermaphrodite ones that were produced in vitro through the hormonal treatment of ...
Jun 3, 2009 ... 4Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular, Sciences, University Putra. Malaysia. 5Malaysian Agriculture Research and Development Institute (MARDI). Accepted 18 May, 2009. Nine Differentially Expressed Genes (DEGs) were detected in the five floral organs ...
Impatiens walleriana is currently among the most valuable and widely cultivated floriculture crops in the world. Highly floriferous cultivars are a primary goal for breeders of I. walleriana. Although breeders have selected for floriferousness, little consideration has been given to floral longevity...
This experiment was designed to study the floral structure, pollen morphology and the potential pollen viability of five Musa genotypes obtained from the Musa field ... Three different types of pollen were encountered viz, big, moderate and small pollens with corresponding big, moderate and small apertures and pores.
Laura A. Burkle; Justin B. Runyon
The effects of climate change on species interactions are poorly understood. Investigating the mechanisms by which species interactions may shift under altered environmental conditions will help form a more predictive understanding of such shifts. In particular, components of climate change have the potential to strongly influence floral volatile organic...
Dubois, Annick; Remay, Arnaud; Raymond, Olivier; Balzergue, Sandrine; Chauvet, Aurélie; Maene, Marion; Pécrix, Yann; Yang, Shu-Hua; Jeauffre, Julien; Thouroude, Tatiana; Boltz, Véronique; Martin-Magniette, Marie-Laure; Janczarski, Stéphane; Legeai, Fabrice; Renou, Jean-Pierre; Vergne, Philippe; Le Bris, Manuel; Foucher, Fabrice; Bendahmane, Mohammed
Cultivated for centuries, the varieties of rose have been selected based on a number of flower traits. Understanding the genetic and molecular basis that contributes to these traits will impact on future improvements for this economically important ornamental plant. In this study, we used scanning electron microscopy and sections of meristems and flowers to establish a precise morphological calendar from early rose flower development stages to senescing flowers. Global gene expression was investigated from floral meristem initiation up to flower senescence in three rose genotypes exhibiting contrasted floral traits including continuous versus once flowering and simple versus double flower architecture, using a newly developed Affymetrix microarray (Rosa1_Affyarray) tool containing sequences representing 4765 unigenes expressed during flower development. Data analyses permitted the identification of genes associated with floral transition, floral organs initiation up to flower senescence. Quantitative real time PCR analyses validated the mRNA accumulation changes observed in microarray hybridizations for a selection of 24 genes expressed at either high or low levels. Our data describe the early flower development stages in Rosa sp, the production of a rose microarray and demonstrate its usefulness and reliability to study gene expression during extensive development phases, from the vegetative meristem to the senescent flower.
A study of the floral morphology of the 32 Polystachya Hook. species in Nigeria, all occurring in the wild, was undertaken in search of simple, non-technical characters for their identification. The study has revealed that each lip is distinctive and can be recognized on the basis of their macroscopical and microscopical ...
Soler, C.; Gil, M.I.; Garcia-Viguera, C.; Tomás-Barberán, F.A.
The flavonoid profiles of 12 different unifloral French honey samples were analysed by HPLC to evaluate if these substances could be used as markers of the floral origin of honey. In this analysis, the characteristic flavonoids from propolis and/or beeswax (chrysin, galangin, tectochrysin,
Gupta, Alok K; Schauvinhold, Ines; Pichersky, Eran; Schiestl, Florian P
Floral signaling, especially through floral scent, is often highly complex, and little is known about the molecular mechanisms and evolutionary causes of this complexity. In this study, we focused on the evolution of "floral scent genes" and the associated changes in their functions in three closely related orchid species of the genus Gymnadenia. We developed a benchmark repertoire of 2,571 expressed sequence tags (ESTs) in Gymnadenia odoratissima. For the functional characterization and evolutionary analysis, we focused on eugenol synthase, as eugenol is a widespread and important scent compound. We obtained complete coding complementary DNAs (cDNAs) of two copies of putative eugenol synthase genes in each of the three species. The proteins encoded by these cDNAs were characterized by expression and testing for activity in Escherichia coli. While G. odoratissima and Gymnadenia conopsea enzymes were found to catalyze the formation of eugenol only, the Gymnadenia densiflora proteins synthesize eugenol, as well as a smaller amount of isoeugenol. Finally, we showed that the eugenol and isoeugenol producing gene copies of G. densiflora are evolutionarily derived from the ancestral genes of the other species producing only eugenol. The evolutionary switch from production of one to two compounds evolved under relaxed purifying selection. In conclusion, our study shows the molecular bases of eugenol and isoeugenol production and suggests that an evolutionary transition in a single gene can lead to an increased complexity in floral scent emitted by plants.
The spikelet has an indeterminate rachilla with distichously arranged glumes, and the floral ontogenetic pattern is similar to that of other Cyperoideae. The diagnostic laterally compressed nutlets can be observed in the ontogenetic phase, where the dorsiventrally orientated stigma primordia give rise to a laterally flattened ...
Benedito, V.A.; Angenent, G.C.; Tuyl, van J.M.; Krens, F.A.
Because lily (Lilium longiflorum Thunb.) is an important cut-flower crop, molecular characterisation of genes that are involved in flower morphology could help breeders to develop novel floral architectures in this species. The early ABC model for flower development emerged more than 10 years ago
Senna (Cassia) corymbosa is an ornamental plant with asymmetric flower in which petals and stamens are also involved in floral asymmetry. The pollen number of abaxial lateral stamen (AL), abaxial median stamen (AM) and middle stamen (MI) are descended in sequence. In field, the insects of visiting flowers are ...
Goslin, Kevin; Zheng, Beibei; Serrano-Mislata, Antonio; Rae, Liina; Ryan, Patrick T; Kwaśniewska, Kamila; Thomson, Bennett; Ó'Maoiléidigh, Diarmuid S; Madueño, Francisco; Wellmer, Frank; Graciet, Emmanuelle
The transcription factors LEAFY (LFY) and APETALA1 (AP1), together with the AP1 paralog CAULIFLOWER (CAL), control the onset of flower development in a partially redundant manner. This redundancy is thought to be mediated, at least in part, through the regulation of a shared set of target genes. However, whether these genes are independently or cooperatively regulated by LFY and AP1/CAL is currently unknown. To better understand the regulatory relationship between LFY and AP1/CAL and to obtain deeper insights into the control of floral initiation, we monitored the activity of LFY in the absence of AP1/CAL function. We found that the regulation of several known LFY target genes is unaffected by AP1/CAL perturbation, while others appear to require AP1/CAL activity. Furthermore, we obtained evidence that LFY and AP1/CAL control the expression of some genes in an antagonistic manner. Notably, these include key regulators of floral initiation such as TERMINAL FLOWER1 ( TFL1 ), which had been previously reported to be directly repressed by both LFY and AP1. We show here that TFL1 expression is suppressed by AP1 but promoted by LFY. We further demonstrate that LFY has an inhibitory effect on flower formation in the absence of AP1/CAL activity. We propose that LFY and AP1/CAL act as part of an incoherent feed-forward loop, a network motif where two interconnected pathways or transcription factors act in opposite directions on a target gene, to control the establishment of a stable developmental program for the formation of flowers. © 2017 American Society of Plant Biologists. All Rights Reserved.
Full Text Available Foram encontrados três morfos florais em Valeriana scandens L.: flor perfeita, flor pistilada 1 e flor pistilada 2. A perfeita possui corola maior que a dos demais morfos, com lobos reflexos na antese, giba proeminente e localizada na porção proximal do tubo floral; anteras maiores que as dos demais morfos, com pólen viável; estilete curto e estigma incluso, o menor ovário e saco embrionário estruturalmente normal, semelhante ao dos demais morfos. A pistilada 1 possui a giba menos proeminente, corola de tamanho intermediário em relação aos demais morfos, lobos radiais na antese; anteras pequenas, sem pólen e estilete longo e estigma exserto. A pistilada 2 possui lobos radiais na antese, anteras de comprimento semelhante às da perfeita, mas de menor largura, com pólen inviável; estilete mais curto, tal como o da flor perfeita, e estigma exserto, tal como o da flor pistilada 1. Nos três morfos, o nectário é formado por tricomas secretores unicelulares situados na epiderme da face interna da giba, e suas sementes são viáveis. As flores pistilada 2 e perfeita apresentam um septo que isola a giba do restante do tubo floral, formando uma câmara nectarífera. V. scandens L. é ginomonóica-ginodióica, expressão sexual inédita em Valerianaceae.Three floral morphs were found in Valeriana scandens L.: perfect, pistillate 1, and pistillate 2. In perfect flowers, the corolla is longer than in the other morphs, with reflexed lobes at anthesis and a prominent gibbus at the tube base; anthers are longer and contain viable pollen grains; the pistil has a short included style/stigma and the smallest ovary, but a structurally normal embryo sac similar to that of the other morphs. In pistillate 1 flowers, the corolla is intermediate in size, and has radially displayed lobes at anthesis, and a softly prominent gibbus; anthers are small and devoid of pollen; the pistil shows a long exerted style/stigma. In pistillate 2 flowers, the corolla
Full Text Available siRNA and microRNA are promising therapeutic agents, which are engaged in a natural mechanism called RNA interference that modulates gene expression posttranscriptionally. For intracellular delivery of such nucleic acid triggers, we use sequence-defined cationic polymers manufactured through solid phase chemistry. They consist of an oligoethanamino amide core for siRNA complexation and optional domains for nanoparticle shielding and cell targeting. Due to the small size of siRNA, electrostatic complexes with polycations are less stable, and consequently intracellular delivery is less efficient. Here we use DNA oligomers as adaptors to increase size and charge of cargo siRNA, resulting in increased polyplex stability, which in turn boosts transfection efficiency. Extending a single siRNA with a 181-nucleotide DNA adaptor is sufficient to provide maximum gene silencing aided by cationic polymers. Interestingly, this simple strategy was far more effective than merging defined numbers (4–10 of siRNA units into one DNA scaffolded construct. For DNA attachment, the 3′ end of the siRNA passenger strand was beneficial over the 5′ end. The impact of the attachment site however was resolved by introducing bioreducible disulfides at the connection point. We also show that DNA adaptors provide the opportunity to readily link additional functional domains to siRNA. Exemplified by the covalent conjugation of the endosomolytic influenza peptide INF-7 to siRNA via a DNA backbone strand and complexing this construct with a targeting polymer, we could form a highly functional polyethylene glycol–shielded polyplex to downregulate a luciferase gene in folate receptor–positive cells.
Alario, Anthony F; Pirie, Christopher G; Pizzirani, Stefano
To describe anterior segment fluorescein angiography (ASFA) of the normal feline eye using a digital single-lens reflex (dSLR) camera adaptor. Ten cats free of ocular and systemic disease were evaluated. All cats received maropitant citrate (1.0 mg/kg SQ) and diphenhydramine (2.0 mg/kg SQ) 20 min prior to anesthesia using propofol (4 mg/kg IV bolus, 0.2 mg/kg/min CRI). Standard color and red-free images were obtained prior to the administration of 10% sodium fluorescein (20 mg/kg IV). Imaging was performed using a dSLR camera (Canon 7D), dSLR camera adaptor, camera lens (Canon EF-S 60 mm f/2.8 macro), and an accessory flash (Canon 580EXII). Imaging occurred at a rate of 1/second immediately following IV bolus of sodium fluorescein for a total of 30 s, then at 1, 2, 3, 4, 5, and 10 min. Ten cats with an average age of 3.7 ± 0.9 years and various iris colors were imaged. Arterial, capillary, and venous phases occurred 4.6, 7.8, and 8.9 s postinjection, respectively. Visibility of the vasculature was not impaired by the degree of iris pigmentation. Patency of a persistent pupillary membrane was noted in one cat. Vessel leakage was common, as well as, leakage into the aqueous humor. Proper patient positioning and restricted ocular movements were critical. No adverse events were noted. This study demonstrates ASFA findings in normal feline eyes using a cost-effective dSLR camera adaptor. Fluorescein leakage from vessels and into the aqueous humor was a common finding. Visibility of iris vasculature was not impaired by the degree of iris pigmentation. © 2012 American College of Veterinary Ophthalmologists.
Alario, Anthony F; Pirie, Christopher G; Pizzirani, Stefano
To describe anterior segment fluorescein angiography (ASFA) of the normal canine eye using two different sedation/anesthetic protocols and a digital single lens-reflex (dSLR) camera adaptor. Dogs free of ocular and systemic disease were used for this study. Dogs received maropitant citrate (1.0 mg/kg SQ) and diphenhydramine (2.0mg/kg SQ) 20min prior to butorphanol [n = 6] (0.2 mg/kg IV) or propofol [n=6] (4 mg/kg IV bolus, 0.2 mg/kg/min CRI). Standard color and red-free images were obtained prior to administration of 10% sodium fluorescein (20 mg/kg IV). Image acquisition was performed using a dSLR camera (Canon 7D), dSLR camera adaptor, camera lens (Canon EF-S 60 mm f/2.8 macro), and an accessory flash (Canon 580EXII). Imaging occurred at a rate of 1/s immediately following bolus for a total of 30 s, then at 1, 2, 3, 4, 5, and 10 min. Twelve dogs with a combined mean age of 5.1 years and various iris colors were imaged. Arterial, capillary, and venous phases were identified and time sequences recorded. Visibility of the vascular pattern was inversely related to iris pigmentation. Complete masking of blood flow was noted with heavily pigmented irises. Vessel leakage was noted in some eyes. Proper patient positioning and restricted ocular movements were critical in acquiring quality images. No adverse events were noted. This study demonstrated that quality high resolution ASFA images were obtainable using a novel dSLR camera adaptor. ASFA of the normal canine eye is limited to irises, which are moderately to poorly pigmented. Use of general anesthesia produced higher quality images and is recommended for ASFA in the dog. © 2012 American College of Veterinary Ophthalmologists.
Oda, Atsushi; Higuchi, Yohei; Hisamatsu, Tamotsu
A wide variety of physiological processes including flowering are controlled by the circadian clock in plants. In Arabidopsis, LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) constitute the central oscillator, and their gain of function and loss of function disrupt the circadian clock and affect flowering time through FLOWERING LOCUS T (FT), a gene encoding a florigen. Chrysanthemum is a typical short-day (SD) plant and responds to shortening of day length by the transition from the vegetative to reproductive phase. We identified FLOWERING LOCUS T-LIKE 3 (FTL3) and ANTI-FLORIGENIC FT/TFL1 FAMILY PROTEIN (AFT) as a florigen and antiflorigen, respectively, in a wild diploid chrysanthemum (Chrysanthemum seticuspe f. boreale). CsFTL3 and CsAFT are induced under SD or a noninductive photoperiod, respectively, and their balance determines the floral transition and anthesis. Meanwhile, the time-keeping mechanism that regulates the photoperiodic flowering in chrysanthemum is poorly understood. Here, we focused on a LHY/CCA1-like gene called CsLHY in chrysanthemum. We fused CsLHY to a gene encoding short transcriptional repressor domain (SRDX) and constitutively expressed it in chrysanthemum. Although the transcription of clock-related genes was conditionally affected, circadian rhythm was not completely disrupted in CsLHY-SRDX transgenic plants. These plants formed almost the same number of leaves before floral transition under SD and long-day conditions. Thus, CsLHY-SRDX chrysanthemum showed photoperiod-insensitive floral transition, but further development of the capitulum was arrested, and anthesis was not observed. Simultaneously with the flowering phenotype, CsFTL3 and CsAFT were downregulated in CsLHY-SRDX transgenic plants. These results suggest that CsLHY-SRDX affects CsFTL3 and CsAFT expression and causes photoperiod-insensitive floral transition without a severe defect in the circadian clock. Copyright © 2017 Elsevier B.V. All rights
Patel, Shivali M; Leon-Villapalos, Jorge
There has been much media attention in recent years on laptops and their accessories overheating and even causing fires. Here, the authors report a case of a laptop power adaptor causing a full thickness burn requiring surgical intervention in a young, fit man. The total contact time was less than 1 h. Initial surgical management involved debridement and allografting of the wound due to a concomitant cellulitis. A week later, once the cellulitis had resolved, an autograft was applied. The graft take was satisfactory (100%) and the patient had a good postoperative outcome.
Jaligot, Estelle; Adler, Sophie; Debladis, Émilie; Beulé, Thierry; Richaud, Frédérique; Ilbert, Pascal; Finnegan, E Jean; Rival, Alain
The large-scale clonal propagation of oil palm (Elaeis guineensis) is being stalled by the occurrence of the mantled somaclonal variation. Indeed, this abnormality which presents a homeotic-like conversion of male floral organs into carpelloid structures, hampers oil production since the supernumerary female organs are either sterile or produce fruits with poor oil yields. In the last 15 years, the prevailing point of view on the origin of the mantled floral phenotype has evolved from a random mutation event triggered by in vitro culture to a hormone-dependent dysfunction of gene regulation processes. In this review, we retrace the history of the research on the mantled variation in the light of the parallel advances made in the understanding of plant development regulation in model systems and more specifically in the role of epigenetic mechanisms. An overview of the current state of oil palm genomic and transcriptomic resources, which are key to any comparison with model organisms, is given. We show that, while displaying original characteristics, the mantled phenotype of oil palm is morphologically, and possibly molecularly, related to MADS-box genes mutants described in model plants. We also discuss the occurrence of comparable floral phenotypes in other palm species. Beyond its primary interest in the search for discriminating markers against an economically crippling phenotype, the study of the mantled abnormality also provides a unique opportunity to investigate the regulation of reproductive development in a perennial tropical palm. On the basis of recent results, we propose that future efforts should concentrate on the epigenetic regulation targeting MADS-box genes and transposable elements of oil palm, since both types of sequences are most likely to be involved in the mantled variant phenotype.
Rosas-Guerrero, Víctor; Quesada, Mauricio; Armbruster, W Scott; Pérez-Barrales, Rocío; Smith, Stacey DeWitt
Natural selection should reduce phenotypic variation and increase integration of floral traits involved in placement of pollen grains on stigmas. In this study, we examine the role of pollinators and breeding system on the evolution of floral traits by comparing the patterns of floral phenotypic variances and covariances in 20 Ipomoea species that differ in their level of pollination specialization and pollinator dependence incorporating phylogenetic relatedness. Plants with specialized pollination (i.e., those pollinated by one functional group or by few morphospecies) displayed less phenotypic variation and greater floral integration than generalist plants. Self-compatible species also displayed greater floral integration than self-incompatible species. Floral traits involved in pollen placement and pick up showed less variation and greater integration than floral traits involved in pollinator attraction. Analytical models indicate that both breeding system and the number of morphospecies had significant effects on floral integration patterns although only differences in the former were significant after accounting for phylogeny. These results suggest that specialist/self-compatible plants experience more consistent selection on floral traits than generalist/self-incompatible plants. Furthermore, pollinators and breeding system promote integration of floral traits involved in pollen placement and pick up rather than integration of the whole flower. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.
Naudin, Cécile; Chevalier, Clément; Roche, Serge
Protein phosphorylation on tyrosine (Tyr) residues has evolved as an important mechanism to coordinate cell communication in multicellular organisms. The importance of this process has been revealed by the discovery of the prominent oncogenic properties of tyrosine kinases (TK) upon deregulation of their physiological activities, often due to protein overexpression and/or somatic mutation. Recent reports suggest that TK oncogenic signaling is also under the control of small adaptor proteins. These cytosolic proteins lack intrinsic catalytic activity and signal by linking two functional members of a catalytic pathway. While most adaptors display positive regulatory functions, a small group of this family exerts negative regulatory functions by targeting several components of the TK signaling cascade. Here, we review how these less studied adaptor proteins negatively control TK activities and how their loss of function induces abnormal TK signaling, promoting tumor formation. We also discuss the therapeutic consequences of this novel regulatory mechanism in human oncology. PMID:26788993
Naudin, Cécile; Chevalier, Clément; Roche, Serge
Protein phosphorylation on tyrosine (Tyr) residues has evolved as an important mechanism to coordinate cell communication in multicellular organisms. The importance of this process has been revealed by the discovery of the prominent oncogenic properties of tyrosine kinases (TK) upon deregulation of their physiological activities, often due to protein overexpression and/or somatic mutation. Recent reports suggest that TK oncogenic signaling is also under the control of small adaptor proteins. These cytosolic proteins lack intrinsic catalytic activity and signal by linking two functional members of a catalytic pathway. While most adaptors display positive regulatory functions, a small group of this family exerts negative regulatory functions by targeting several components of the TK signaling cascade. Here, we review how these less studied adaptor proteins negatively control TK activities and how their loss of function induces abnormal TK signaling, promoting tumor formation. We also discuss the therapeutic consequences of this novel regulatory mechanism in human oncology.
Full Text Available Here, we report on the results of an experimental study that assessed the visitation frequency of wild bees to conspecific flowers with different sized floral guides. UV absorbent floral guides are ubiquitous in Angiosperms, yet surprisingly little is known about conspecific variation in these guides and very few studies have evaluated pollinator response to UV guide manipulation. This is true despite our rich understanding about learning and color preferences in bees. Historical dogma indicates that flower color serves as an important long-range visual signal allowing pollinators to detect the flowers, while floral guides function as close-range signals that direct pollinators to a reward. We initiated the work presented here by first assessing the population level variation in UV absorbent floral guides for conspecific flowers. We assessed two species, Rudbeckia hirta and R. fulgida. We then used several petal cut-and-paste experiments to test whether UV floral guides can also function to attract visitors. We manipulated floral guide size and evaluated visitation frequency. In all experiments, pollinator visitation rates were clearly associated with floral guide size. Diminished floral guides recruited relatively few insect visitors. Exaggerated floral guides recruited more visitors than smaller or average sized guides. Thus, UV floral guides play an important role in pollinator recruitment and in determining the relative attractiveness of conspecific flower heads. Consideration of floral guides is therefore important when evaluating the overall conspicuousness of flower heads relative to background coloration. This work raises the issue of whether floral guides serve as honest indicators of reward, since guide size varies in nature for conspecific flowers at the same developmental stage and since preferences for larger guides were found. To our knowledge, these are the first cut-and-paste experiments conducted to examine whether UV absorbent
Zhao, Baoyu; Shu, Chang; Gao, Xinsheng; Sankaran, Banumathi; Du, Fenglei; Shelton, Catherine L; Herr, Andrew B; Ji, Jun-Yuan; Li, Pingwei
Type I IFNs are key cytokines mediating innate antiviral immunity. cGMP-AMP synthase, ritinoic acid-inducible protein 1 (RIG-I)-like receptors, and Toll-like receptors recognize microbial double-stranded (ds)DNA, dsRNA, and LPS to induce the expression of type I IFNs. These signaling pathways converge at the recruitment and activation of the transcription factor IRF-3 (IFN regulatory factor 3). The adaptor proteins STING (stimulator of IFN genes), MAVS (mitochondrial antiviral signaling), and TRIF (TIR domain-containing adaptor inducing IFN-β) mediate the recruitment of IRF-3 through a conserved pLxIS motif. Here we show that the pLxIS motif of phosphorylated STING, MAVS, and TRIF binds to IRF-3 in a similar manner, whereas residues upstream of the motif confer specificity. The structure of the IRF-3 phosphomimetic mutant S386/396E bound to the cAMP response element binding protein (CREB)-binding protein reveals that the pLxIS motif also mediates IRF-3 dimerization and activation. Moreover, rotavirus NSP1 (nonstructural protein 1) employs a pLxIS motif to target IRF-3 for degradation, but phosphorylation of NSP1 is not required for its activity. These results suggest a concerted mechanism for the recruitment and activation of IRF-3 that can be subverted by viral proteins to evade innate immune responses.
High-throughput generation of bispecific molecules promises to expedite the discovery of new molecular therapeutics and guide engineering of novel multifunctional constructs. However, high synthesis complexity and cost have hampered the discovery of bispecific molecules in drug development and biomedical research. Herein we describe a simple solid-phase bioconjugation procedure for preparation of Protein A(G,L)-PEG-Streptavidin heterobifunctional adaptors (with 1:1:1 stoichiometry), which enable self-assembly of unmodified antibodies and biotinylated molecules into bispecific targeting ligands in a versatile mix-and-use manner. Utility of such adaptors is demonstrated by assembly of anti-CD3 and anti-Her2 antibodies into bispecific CD3xHer2 targeting ligands, which efficiently drive T-cell-mediated lysis of Her2-positive cancer cells. In comparison to bioconjugation in solution, the solid-phase procedure described here offers precise stoichiometry control, ease of purification, and high yield of functional conjugates. Simplicity and versatility should prove this methodology instrumental for preparation of bispecific ligands, as well as for high-throughput screening of bispecific combinations, before proceeding to synthesis of lead candidates via recombinant engineering or chemical cross-linking. PMID:25010411
Bergamin, E.; Hallock, P; Burden, S; Hubbard, S
Formation of the vertebrate neuromuscular junction requires, among others proteins, Agrin, a neuronally derived ligand, and the following muscle proteins: LRP4, the receptor for Agrin; MuSK, a receptor tyrosine kinase (RTK); and Dok7 (or Dok-7), a cytoplasmic adaptor protein. Dok7 comprises a pleckstrin-homology (PH) domain, a phosphotyrosine-binding (PTB) domain, and C-terminal sites of tyrosine phosphorylation. Unique among adaptor proteins recruited to RTKs, Dok7 is not only a substrate of MuSK, but also an activator of MuSK's kinase activity. Here, we present the crystal structure of the Dok7 PH-PTB domains in complex with a phosphopeptide representing the Dok7-binding site on MuSK. The structure and biochemical data reveal a dimeric arrangement of Dok7 PH-PTB that facilitates trans-autophosphorylation of the kinase activation loop. The structure provides the molecular basis for MuSK activation by Dok7 and for rationalizing several Dok7 loss-of-function mutations found in patients with congenital myasthenic syndromes.
Barres, Romain; Gonzalez, Teresa; Le Marchand-Brustel, Yannick
APS (adaptor protein with PH and SH2 domains) is an adaptor protein phosphorylated by several tyrosine kinase receptors including the insulin receptor. To identify novel binding partners of APS, we performed yeast two-hybrid screening. We identified Enigma, a PDZ and LIM domain-containing protein...... that was previously shown to be associated with the actin cytoskeleton. In HEK 293 cells, Enigma interacted specifically with APS, but not with the APS-related protein SH2-B. This interaction required the NPTY motif of APS and the LIM domains of Enigma. In NIH-3T3 cells that express the insulin receptor, Enigma...... and APS were partially co-localised with F-actin in small ruffling structures. Insulin increased the complex formation between APS and Enigma and their co-localisation in large F-actin containing ruffles. While in NIH-3T3 and HeLa cells the co-expression of both Enigma and APS did not modify the actin...
Diaz, Fernando; Gravotta, Diego; Deora, Ami; Schreiner, Ryan; Schoggins, John; Falck-Pedersen, Erik; Rodriguez-Boulan, Enrique
Adenoviruses invading the organism via normal digestive or respiratory routes require the Coxsackie-adenovirus receptor (CAR) to infect the epithelial barrier cells. Because CAR is a component of tight junctions and the basolateral membrane and is normally excluded from the apical membrane, most epithelia are resistant to adenoviruses. However, we discovered that a specialized epithelium, the retinal pigment epithelium (RPE), anomalously expressed CAR at the apical surface and was highly susceptible to adenovirus infection. These properties of RPE cells correlated with the absence of the epithelial-specific clathrin adaptor AP1B. Furthermore, knockdown of this basolateral sorting adaptor in adenovirus-resistant MDCK cells promoted apical localization of CAR and increased dramatically Adenovirus infectivity. Targeting assays showed that AP1B is required for accurate basolateral recycling of CAR after internalization. AP1B knock down MDCK cells missorted CAR from recycling endosomes to the apical surface. In summary, we have characterized the cellular machinery responsible for normal sorting of an adenovirus receptor and illustrated how tissue-specific variations in such machinery result in drastic changes in tissue-susceptibility to adenoviruses.
Anselm H.C. Horn
Full Text Available The efficiency of many cellular processes relies on the defined interaction among different proteins within the same metabolic or signaling pathway. Consequently, a spatial colocalization of functionally interacting proteins has frequently emerged during evolution. This concept has been adapted within the synthetic biology community for the purpose of creating artificial scaffolds. A recent advancement of this concept is the use of peptide motifs and their cognate adaptor domains. SH2, SH3, GBD, and PDZ domains have been used most often in research studies to date. The approach has been successfully applied to the synthesis of a variety of target molecules including catechin, D-glucaric acid, H2, hydrochinone, resveratrol, butyrate, gamma-aminobutyric acid, and mevalonate. Increased production levels of up to 77-fold have been observed compared to non-scaffolded systems. A recent extension of this concept is the creation of a covalent linkage between peptide motifs and adaptor domains, which leads to a more stable association of the scaffolded systems and thus bears the potential to further enhance metabolic productivity.
Hailey, M.; Bayuse, T.
Fluid Isolation in the medication vial: Air/ fluid isolation maneuvers were used to move the medication to the septum end of vial. This isolation may be achieved in multiple ways based on the experience of the astronaut with fluid management in microgravity. If vial adaptors/blunt cannula or syringe assembly is inserted into the to vial before fluid isolation commences, the stability of this assembly should be considered in an effort to limit the risk of "slinging off" of the vial during isolation. Alternatively, fluid isolation can be performed prior to attaching the syringe/vial adaptor assembly. Terrestrial practices for medication withdrawal from a nonvented vial require injection of an equivalent amount of air as the expected medication volume prior to withdrawing liquid. In microgravity, this action is still valid, however the injection of additional air into the vial creates a multitude of micro bubbles and increases the volume of medication mixed with air that then must be withdrawn to achieve the desired drug volume in syringe. This practice is more likely to be required when using vials >30ml in size and injection volumes >10mL. It is felt that based on the microgravity flight, the practice of air injection is more of a hindrance than help.
Full Text Available Las plantas emplean diversas señales visuales y olfativas con la finalidad de atraer a los polinizadores que en su mayoría son insectos. Algunas plantas han desarrollado mecanismos, basándose en mensajes olfativos que los hacen únicos para sus polinizadores específicos. Estos mecanismos, así como las variaciones intra- e interespecíficas en el perfil de los aromas florales han evolucionado para determinadas especies. Los aromas florales son un conjunto de compuestos volátiles orgánicos y para su estudio hay varios métodos que requieren de técnicas que cada vez son más eficientes. El uso de estos aromas podría ser una opción en determinados sistemas de polinización, utilizándolos como atrayente de polinizadores o de depredadores y/o herbívoro para incrementar la producción y disminuir los daños por plagas. En este trabajo se revisan las distintas interacciones de los insectos y los aromas florales, los sistemas específicos planta-polinizador, los métodos de análisis, así como algunos patrones o tendencias de estas interacciones y su aplicación e importancia.Plants use visual and olfactory cues to attract pollinators and to allow them to detect the presence of flowers, which most of them are insects. Some plants have evolved with their pollinators, based on the olfactory messages, which make them unique for their specific pollinators. These mechanisms have evolved in certain plants in relation to their pollinators, and there are also inter and intra-specific variation in fragrance cues which show specific chemical profile for each plant species, so insects attracted are specific to them. Most of the floral scents are organic compounds identified with techniques and methodologies which become more specific and efficient along the time. The application of floral scent could be used as a tool in pollination and pest management. In these studies, insect interaction with floral scent is reviewed and specificity of plant
Phongsisay, Vongsavanh; Iizasa, Ei'ichi; Hara, Hiromitsu; Yoshida, Hiroki
Activation of the innate immunity by adjuvants, such as pertussis toxin (PTX), in the presence of autoreactive lymphocytes and antigen mimicry is sufficient to trigger autoimmunity. Toll-like, C-type lectin, and immunglobulin-like receptors play an important role in the innate immunity by sensing a variety of microbial products through several adaptor proteins, including MyD88, DAP12, and FcRγ. This study investigated the interaction between PTX and innate immune components. The direct interactions between coated PTX and receptor-fusion proteins were examined using ELISA-based binding assays. Functionally, PTX-binding receptors could be classified into two groups: inhibition (DAP12-coupled TREM2, ITIM-bearing SIRPα, SIGNR1/SIGNR3/DCSIGN) and activation (MyD88-associated TLR4, DAP12-coupled LMIR5/CD300b, FcRγ-coupled LMIR8/CD300c, CLEC9A, MGL-1). DAP12, MyD88, and FcRγ were selected for further investigation. A comprehensive analysis of gene transcription showed that PTX up-regulated the expression of various inflammatory mediators. DAP12 deficiency resulted in reduction or enhancement of inflammatory responses in a cytokine-specific manner. PTX was able to activate the TREM2-DAP12 signalling pathway. PTX induced lower expression of inflammatory mediators in the absence of FcRγ alone and substantially lost its inflammatory capacity in the absence of both FcRγ and MyD88. PTX was able to activate the MyD88-NF-κB signalling pathway in the presence of TLR2 or TLR4. The inflammatory activity of PTX was completely lost by heating. These results demonstrate that PTX targets the innate immunity through DAP12, FcRγ, and MyD88 providing new insights into the immunobiology of PTX. Copyright © 2016 Elsevier GmbH. All rights reserved.
Engelhorn, Julia; Wellmer, Frank; Carles, Cristel C
Covalent histone modifications and their effects on chromatin state and accessibility play a key role in the regulation of gene expression in eukaryotes. To gain insights into their functions during plant growth and development, the distribution of histone modifications can be analyzed at a genome-wide scale through chromatin immunoprecipitation assays followed by sequencing of the isolated genomic DNA. Here, we present a protocol for systematic analysis of the distribution and dynamic changes of selected histone modifications, during flower development in the model plant Arabidopsis thaliana. This protocol utilizes a previously established floral induction system to synchronize flower development, which allows the collection of sufficient plant material for analysis by genomic technologies. In this chapter, we describe how to use this system to study, from the same set of samples, chromatin and transcriptome dynamics during early stages of flower formation.
Full Text Available ABSTRACT Species of Apocynaceae stand out among angiosperms in having very complex flowers, especially those of asclepiads, which belong to the most derived subfamily (Asclepiadoideae. These flowers are known to represent the highest degree of floral synorganization of the eudicots, and are comparable only to orchids. This morphological complexity may also be understood by observing their glands. Asclepiads have several protective and nuptial secretory structures. Their highly specific and specialized pollination systems are associated with the great diversity of glands found in their flowers. This review gathers data regarding all types of floral glands described for asclepiads and adds three new types (glandular trichome, secretory idioblast and obturator, for a total of 13 types of glands. Some of the species reported here may have dozens of glands of up to 11 types on a single flower, corresponding to the largest diversity of glands recorded to date for a single structure.
Wright, G A; Baker, D D; Palmer, M J; Stabler, D; Mustard, J A; Power, E F; Borland, A M; Stevenson, P C
Plant defense compounds occur in floral nectar, but their ecological role is not well understood. We provide evidence that plant compounds pharmacologically alter pollinator behavior by enhancing their memory of reward. Honeybees rewarded with caffeine, which occurs naturally in nectar of Coffea and Citrus species, were three times as likely to remember a learned floral scent as were honeybees rewarded with sucrose alone. Caffeine potentiated responses of mushroom body neurons involved in olfactory learning and memory by acting as an adenosine receptor antagonist. Caffeine concentrations in nectar did not exceed the bees' bitter taste threshold, implying that pollinators impose selection for nectar that is pharmacologically active but not repellent. By using a drug to enhance memories of reward, plants secure pollinator fidelity and improve reproductive success.
Itoh, Hironori; Izawa, Takeshi
The photoperiodic control of flowering time is essential for the adaptation of plants to variable environments and for successful reproduction. The identification of genes encoding florigens, which had been elusive but were supposedly synthesized in leaves and then transmitted to shoot apices to induce floral transitions, has greatly advanced our understanding of the photoperiodic regulation of flowering. Studies on the photoperiodism of Arabidopsis, a model long-day plant, revealed the molecular mechanisms regulating the expression of the Arabidopsis florigen gene FT, which is gradually induced in response to increase in day length. By contrast, in rice, a model short-day plant, the expression of the florigen gene Hd3a (an FT ortholog in rice) is regulated in an on/off fashion, with strong induction under short-day conditions and repression under long-day conditions. This critical day length dependence of Hd3a expression enables rice to recognize a slight change in the photoperiod as a trigger to initiate floral induction. Rice possesses a second florigen gene, RFT1, which can be expressed to induce floral transition under non-inductive long-day conditions. The complex transcriptional regulation of florigen genes and the resulting precise control over flowering time provides rice with the adaptability required for a crop species of increasing global importance.
Timing of the floral transition and inflorescence development strongly affect yield in barley (Hordeum vulgare). Therefore, we examined the effects of daylength and the photoperiod response gene PHOTOPERIOD1 (Ppd-H1) on barley development and analyzed gene expression changes in the developing leaves and main shoot apices (MSAs) of barley by RNA sequencing. The daylength sensitivity of MSA development had two phases, floret primordia initiated under long and short days, whereas successful inflorescence development occurred only under long days. The transcripts associated with floral transition were largely regulated independently of photoperiod and allelic variation at Ppd-H1. The photoperiod- and Ppd-H1-dependent differences in inflorescence development and flower fertility were associated with the induction of barley FLOWERING LOCUS T orthologs: FT1 in leaves and FT2 in MSAs. FT1 expression was coregulated with transcripts involved in nutrient transport, carbohydrate metabolism, and cell cycle regulation, suggesting that FT1 might alter source-sink relationships. Successful inflorescence development correlated with upregulation of FT2 and transcripts related to floral organ development, phytohormones, and cell cycle regulation. Identification of photoperiod and stage-specific transcripts gives insights into the regulation of reproductive development in barley and provides a resource for investigation of the complexities of development and yield in temperate grasses. PMID:26307377
Gururaj, Sushmitha; Evely, Katherine M; Pryce, Kerri D; Li, Jun; Qu, Jun; Bhattacharjee, Arin
The sodium-activated potassium (K Na ) channel Kcnt1 (Slack) is abundantly expressed in nociceptor (pain-sensing) neurons of the dorsal root ganglion (DRG), where they transmit the large outward conductance I KNa and arbitrate membrane excitability. Slack channel expression at the DRG membrane is necessary for their characteristic firing accommodation during maintained stimulation, and reduced membrane channel density causes hyperexcitability. We have previously shown that in a pro-inflammatory state, a decrease in membrane channel expression leading to reduced Slack-mediated I KNa expression underlies DRG neuronal sensitization. An important component of the inflammatory milieu, PKA internalizes Slack channels from the DRG membrane, reduces I KNa , and produces DRG neuronal hyperexcitability when activated in cultured primary DRG neurons. Here, we show that this PKA-induced retrograde trafficking of Slack channels also occurs in intact spinal cord slices and that it is carried out by adaptor protein-2 (AP-2) via clathrin-mediated endocytosis. We provide mass spectrometric and biochemical evidence of an association of native neuronal AP-2 adaptor proteins with Slack channels, facilitated by a dileucine motif housed in the cytoplasmic Slack C terminus that binds AP-2. By creating a competitive peptide blocker of AP-2-Slack binding, we demonstrated that this interaction is essential for clathrin recruitment to the DRG membrane, Slack channel endocytosis, and DRG neuronal hyperexcitability after PKA activation. Together, these findings uncover AP-2 and clathrin as players in Slack channel regulation. Given the significant role of Slack in nociceptive neuronal excitability, the AP-2 clathrin-mediated endocytosis trafficking mechanism may enable targeting of peripheral and possibly, central neuronal sensitization. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Kuang, Yulan; Li, Qifang; Ning, Wangyun
Cut flower production in Yunnan accounts for 80% nationwide. In order to expand the Yunnan Flower sales channels, the promotion of the development of e-commerce is necessary. In 2012 China's online shopping users reached 247 million people, but e-commerce of fresh flowers lagged behind due to the constraints of preservation facilities and logistics cost. The analysis of the factors restricting the development of floral e-commerce and the proposition of solutions to this problem can promote fa...
Full Text Available Penelitian ini menarik untuk dilakukan karena sangat bervariasinya suku Leguminosae dimana salah satu subsukunya adalah Lotoideae. Struktur morfologi bunga dari anggota subsuku digunakan sebagai karakter state dalam membedakan anggota-anggotanya. Tujuan dari penelitian ini adalah untuk mengetahui variasi morfologi floral vegetatif anggota subsuku Lotoideae serta untuk mengetahui variasi morfologi floral generatif anggota subsuku Lotoideae. Metode yang digunakan adalah eksplorasi ke Yogjakarta dan sekitarnya untuk mencari bunga tanaman anggota subsuku Lotoideae, kemudian dilakukan pengamatan terhadap struktur morfologi floralnya, baik vegetatif maupun generatif. Selain itu juga dilakukan pengamatan terhadap morfologi serbuk sari yang sebelumnya telah dibuat preparat dengan menggunaan metode asetolisis. Data yang diperoleh berupa hasil pengukuran berbagai parameter bunga seperti petala, sepala, benangsari, serbuk sari, androecium, gynaecium, dan data hasil pengukuran serbuk sari dianalisis secara deskriptif.Hasil dari penelitian ini adalah Variasi morfologi floral vegetatif anggota sub-suku Lotoideae yaitu memiliki kelopak yang berbeda pada ukurannya sedangkan persamaannya berjumlah 5, aestivationya berlekatan. Perbedaan mahkotanya adalah pada warna dan ukuran dari masing-masing bagian bunga,sedangkan persamaannya terdiri atas 5 petala, bentuknya menyerupai kupu-kupu, Bentuk mahkotanya terbagi 3 yaitu, bendera di bagian terluar merupakan bagian yang terlebar, sayap dengan ujung runcing dan lunas yang saling berlekatan berbentuk seperti sekoci. Variasi morfologi floral generatif anggota subsuku Lotoideae yaitu memiliki perbedaan pada jumlah berkas. Persamaan benangsarinya berjumlah 10, dan tersusun dalam berkas. Gynaecium perbedaannya adalah pada ukuran dan warna, sedangkan persamaannya adalah posisi ovarium menumpang, jumlah carpel 1, plasentasi marginal, Aestivatio bebas. Ciri pada serbuksarinya berbeda dalam ukuran, aperture
Endress, Peter K.
In basal angiosperms (including ANITA grade, magnoliids, Choranthaceae, Ceratophyllaceae) almost all bisexual flowers are dichogamous (with male and female functions more or less separated in time), and nearly 100 per cent of those are protogynous (with female function before male function). Movements of floral parts and differential early abscission of stamens in the male phase are variously associated with protogyny. Evolution of synchronous dichogamy based on the day/night rhythm and anthesis lasting 2 days is common. In a few clades in Magnoliales and Laurales heterodichogamy has also evolved. Beetles, flies and thrips are the major pollinators, with various degrees of specialization up to large beetles and special flies in some large-flowered Nymphaeaceae, Magnoliaceae, Annonaceae and Aristolochiaceae. Unusual structural specializations are involved in floral biological adaptations (calyptras, inner staminodes, synandria and food bodies, and secretory structures on tepals, stamens and staminodes). Numerous specializations that are common in monocots and eudicots are absent in basal angiosperms. Several families are poorly known in their floral biology. PMID:20047868
Minaei, Saeid; Shafiee, Sahameh; Polder, Gerrit; Moghadam-Charkari, Nasrolah; van Ruth, Saskia; Barzegar, Mohsen; Zahiri, Javad; Alewijn, Martin; Kuś, Piotr M.
Nondestructive methods are of utmost importance for honey characterization. This study investigates the potential application of VIS-NIR hyperspectral imaging for detection of honey flower origin using machine learning techniques. Hyperspectral images of 52 honey samples were taken in transmittance mode in the visible/near infrared (VIS-NIR) range (400-1000 nm). Three different machine learning algorithms were implemented to predict honey floral origin using honey spectral images. These methods, included radial basis function (RBF) network, support vector machine (SVM), and random forest (RF). Principal component analysis (PCA) was also exploited for dimensionality reduction. According to the obtained results, the best classifier (RBF) achieved a precision of 94% in a fivefold cross validation experiment using only the first two PCs. Mapping of the classifier results to the test set images showed 90% accuracy for honey images. Three types of honey including buckwheat, rapeseed and heather were classified with 100% accuracy. The proposed approach has great potential for honey floral origin detection. As some other honey properties can also be predicted using image features, in addition to floral origin detection, this method may be applied to predict other honey characteristics.
Gocal, G.F.W.; King, R.W.; Blundell, C.A.
Flowering (inflorescence formation) of the grass Lolium temulentum is strictly regulated, occurring rapidly on exposure to a single long day (LD). During floral induction, L. temulentum differs significantly from dicot species such as Arabidopsis in the expression, at the shoot apex, of two APETALA...... are consecutively activated early during flower formation. LtMADS2, when expressed in transgenic Arabidopsis plants under the control of the AP1 promoter, could partially complement the organ number defect of the severe ap1-15 mutant allele, confirming a close relationship between LtMADS2 and AP1....
Hepworth, Shelley R; Klenz, Jennifer E; Haughn, George W
The UNUSUAL FLORAL ORGANS (UFO) gene of Arabidopsis encodes an F-box protein required for the determination of floral-organ and floral-meristem identity. Mutation of UFO leads to dramatic changes in floral-organ type which are well-characterized whereas inflorescence defects are more subtle and less understood. These defects include an increase in the number of secondary inflorescences, nodes that alternate between forming flowers and secondary inflorescences, and nodes in which a single flower is subtended by a bract. Here, we show how inflorescence defects correlate with the abnormal development of floral primordia and establish a temporal requirement for UFO in this process. At the inflorescence apex of ufo mutants, newly formed primordia are initially bract-like. Expression of the floral-meristem identity genes LFY and AP1 are confined to a relatively small adaxial region of these primordia with expression of the bract-identity marker FIL observed in cells that comprise the balance of the primordia. Proliferation of cells in the adaxial region of these early primordia is delayed by several nodes such that primordia appear "chimeric" at several nodes, having visible floral and bract components. However, by late stage 2 of floral development, growth of the bract generally ceases and is overtaken by development of the floral primordium. This abnormal pattern of floral meristem development is not rescued by expression of UFO from the AP1 promoter, indicating that UFO is required prior to AP1 activation for normal development of floral primordia. We propose that UFO and LFY are jointly required in the inflorescence meristem to both promote floral meristem development and inhibit, in a non-cell autonomous manner, growth of the bract.
Wessinger, Carolyn A.; Hileman, Lena C.; Rausher, Mark D.
Distinct floral pollination syndromes have emerged multiple times during the diversification of flowering plants. For example, in western North America, a hummingbird pollination syndrome has evolved more than 100 times, generally from within insect-pollinated lineages. The hummingbird syndrome is characterized by a suite of floral traits that attracts and facilitates pollen movement by hummingbirds, while at the same time discourages bee visitation. These floral traits generally include larg...
Mark W. Chase; Norris H. Williams; Aparacida Donisete de Faria; Kurt M. Neubig; Maria do Carmo E. Amaral; W. Mark Whitten
• Background Floral morphology, particularly the angle of lip attachment to the column, has historically been the fundamental character used in establishing generic limits in subtribe Oncidiinae (Orchidaceae...
Goodrich, Katherine R; Raguso, Robert A
Floral scent is a key component of floral display, and probably one of the first floral attractants linking insect pollinators to the radiation of Angiosperms. In this article, we investigate floral scent in two extra-tropical genera of Annonaceae. We discuss floral scent in the context of differing pollination strategies in these genera, and compare their scent to that of a close tropical relative. Floral volatiles were collected for Annona glabra, Asimina and Deeringothamnus whole flowers and dissected floral organs, using a standardized static-headspace solid phase microextraction method. Scents were analyzed using gas chromatography-mass spectrometry, and identified using known standards. The floral scents of these species are highly dynamic, varying between floral organs, sexual stages and species. Maroon-flowered species of Asimina produce 'yeasty' odors, dominated by fermentation volatiles and occasionally containing sulfurous or nitrogenous compounds. White-flowered species of Asimina and Deeringothamnus produce pleasant odors characterized by lilac compounds, benzenoids and hydrocarbons. Annona glabra produces a strong, fruity-acetonic scent dominated by 3-pentanyl acetate and 1,8-cineole. The fermented/decaying scents of maroon-flowered species of Asimina suggest mimicry-based pollination strategies similar to aroids and stapeliads, whereas the pleasant scents of white-flowered species of Asimina suggest honest, reward-based pollination strategies. The scent of Annona glabra is typical of specialized beetle pollination systems common to tropical Annonaceae.
Full Text Available Abstract Background The Floral Genome Project was initiated to bridge the genomic gap between the most broadly studied plant model systems. Arabidopsis and rice, although now completely sequenced and under intensive comparative genomic investigation, are separated by at least 125 million years of evolutionary time, and cannot in isolation provide a comprehensive perspective on structural and functional aspects of flowering plant genome dynamics. Here we discuss new genomic resources available to the scientific community, comprising cDNA libraries and Expressed Sequence Tag (EST sequences for a suite of phylogenetically basal angiosperms specifically selected to bridge the evolutionary gaps between model plants and provide insights into gene content and genome structure in the earliest flowering plants. Results Random sequencing of cDNAs from representatives of phylogenetically important eudicot, non-grass monocot, and gymnosperm lineages has so far (as of 12/1/04 generated 70,514 ESTs and 48,170 assembled unigenes. Efficient sorting of EST sequences into putative gene families based on whole Arabidopsis/rice proteome comparison has permitted ready identification of cDNA clones for finished sequencing. Preliminarily, (i proportions of functional categories among sequenced floral genes seem representative of the entire Arabidopsis transcriptome, (ii many known floral gene homologues have been captured, and (iii phylogenetic analyses of ESTs are providing new insights into the process of gene family evolution in relation to the origin and diversification of the angiosperms. Conclusion Initial comparisons illustrate the utility of the EST data sets toward discovery of the basic floral transcriptome. These first findings also afford the opportunity to address a number of conspicuous evolutionary genomic questions, including reproductive organ transcriptome overlap between angiosperms and gymnosperms, genome-wide duplication history, lineage
Vandervort, Robert E. (Inventor)
A system, method, and apparatus for a vented launch vehicle adaptor (LVA) for a manned spacecraft with a "pusher" launch abort system are disclosed. The disclosed LVA provides a structural interface between a commercial crew vehicle (CCV) crew module/service module (CM/SM) spacecraft and an expendable launch vehicle. The LVA provides structural attachment of the module to the launch vehicle. It also provides a means to control the exhaust plume from a pusher-type launch abort system that is integrated into the module. In case of an on-pad or ascent abort, which requires the module to jettison away from the launch vehicle, the launch abort system exhaust plume must be safely directed away from critical and dangerous portions of the launch vehicle in order to achieve a safe and successful jettison.
Hailey, Melinda; Bayuse, Tina
The need for a new system of injectable medications aboard the International Space Station (ISS) was identified. It is desired that this system fly medications in their original manufacturer's packaging, allowing the system to comply with United States Pharmacopeia (USP) guidelines while minimizing the resupply frequency due to medication expiration. Pre-filled syringes are desired, however, the evolving nature of the healthcare marketplace requires flexibility in the redesign. If medications must be supplied in a vial, a system is required that allows for the safe withdrawal of medication from the vial into a syringe for administration in microgravity. During two reduced gravity flights, the effectiveness of two versions of a blunt cannula and needleless vial adaptors was evaluated to facilitate the withdrawal of liquid medication from a vial into a syringe for injection. Other parameters assessed included the ability to withdraw the required amount of medication and whether this is dependent on vial size, liquid, or the total volume of fluid within the vial. Injectable medications proposed for flight on ISS were used for this evaluation. Due to differing sizes of vials and the fluid properties of the medications, the needleless vial adaptors proved to be too cumbersome to recommend for use on the ISS. The blunt cannula, specifically the plastic version, proved to be more effective at removing medication from the various sizes of vials and are the recommended hardware for ISS. Fluid isolation within the vials and syringes is an important step in preparing medication for injection regardless of the hardware used. Although isolation is a challenge in the relatively short parabolas during flight, it is not an obstacle for sustained microgravity. This presentation will provide an overview of the products tested as well as the challenges identified during the microgravity flights.
Spigler, Rachel B
Plasticity of floral traits in response to pollination can enable plants to maximize opportunities for pollen import and export under poor pollination conditions, while minimizing costs under favourable ones. Both floral longevity and display are key traits influencing pollination. While pollination-induced flower wilting is widely documented, we lack an understanding of the multifactorial complexity of this response, including the influence of other pollination components, costs of extended longevity and subsequent impacts on floral display. Plasticity of floral longevity was experimentally evaluated in Sabatia angularis in response to multiple pollination factors: pollen addition, removal, and source (self, single-donor outcross, multiple-donor outcross) and timing of pollination. Effects of pollen quantity were further evaluated by exploiting variation in autonomous self-pollen deposition. Delayed pollination costs were tested comparing seed set from early versus late pollinations. Finally, I compared floral display metrics (peak floral display, time to peak flower, flowering duration, mean flowering rate) between experimentally pollinated and control plants. Floral longevity was highly plastic in response to pollen addition and its timing, and the response was dose-dependent but insensitive to pollen source. Pollen removal tended to extend floral longevity, but only insofar as it precluded pollination-induced wilting via autonomous self-pollination. Under delayed pollination, the wilting response was faster and no cost was detected. Pollination further led to reduced peak floral displays and condensed flowering periods. Floral longevity and display plasticity could optimize fitness in S. angularis, a species prone to pollen limitation and high inbreeding depression. Under pollinator scarcity, extended floral longevities offer greater opportunities for pollen receipt and export at no cost to seed set, reproductive assurance via autonomous self-pollination and
Duan, Weike; Zhang, Huijun; Zhang, Bei; Wu, Xiaoting; Shao, Shuaixu; Li, Ying; Hou, Xilin; Liu, Tongkun
Vernalization-mediated demethylation of BrCKA2 (casein kinase II α-subunit) and BrCKB4 (casein kinase II β-subunit) shorten the period of the clock gene BrCCA1 (circadian clock associated 1) in Brassica rapa. Photoperiod and vernalization are two environmental cues involved in the regulation of floral transition, but the ways in which they interact remain unclear. DNA methylation is one of the main mechanisms involved in controlling the functional state of chromatin and gene expression in response to environmental signals. To study the interaction between photoperiod and vernalization in floral transition, we carried out a comparative genomic analysis of genome-wide DNA methylation profiles in normal (CK) and vernalized (CA) leaves from Brassica rapa using methylated-DNA immunoprecipitation sequencing (MeDIP-seq). Two subunits of casein kinase II (CK2), BrCKA2 (catalytic α-subunit of CK2) and BrCKB4 (regulatory β-subunit of CK2), exhibited gradual DNA demethylation and increased expression in vernalized B. rapa. DNA methylation-defective plants demonstrated the causal link between DNA demethylation changes and changes in gene expression. Virus-induced gene silencing (VIGS) of BrCKA2 and BrCKB4 in B. rapa resulted in no change to the period of BrCCA1 (circadian clock associated 1) and a 1-week late flowering time. Finally, we demonstrated that increased levels of BrCKA2 and BrCKB4 in vernalized B. rapa confer elevated CK2 activity, resulting in a shortened period of the clock gene BrCCA1, which plays an important role in perceiving photoperiod in plants. Thus, our results suggest that there is a direct interaction between photoperiod and vernalization through DNA methylation mechanisms.
Frumin, Suembikya; Maeir, Aren M; Kolska Horwitz, Liora; Weiss, Ehud
... of local Near Eastern haplotypes. Building on this, and combining biogeographical methods of Floral List comparisons with archaeological data, we have elucidated the Philistine impact on Southern Levantine floral ecosystem...
María T. Amela García
Full Text Available Un experimento reproductivo muestra que Passiflora foetida es autocompatible. Observaciones de las características florales y de los visitantes durante la antesis, más el análisis del polen transportado, permitieron identificar el síndrome floral (melitofilia y las funciones de cada visitante. La antesis ocurre desde las 6 hasta las 11 hs. Se identificaron 3 fases florales: 1 estigmas por encima de las anteras, 2 estigmas a la altura de las anteras, 3 estigmas por encima de las anteras; los radii, los pétalos y los sépalos se incurvan. Los estigmas están receptivos durante toda la antesis. La concentración de azúcares del néctar es 34 %. El color predominante en el espectro visible es el blanco. En el espectro UV, los estambres y el gineceo contrastan con el limen y el androginóforo; pueden ser una guía de néctar. Tres especies de himenópteros fueron los visitantes más frecuentes y constantes: Ptiloglossa tarsata (Colletidae siempre contactan las anteras y los estigmas cuando liban, transportan un alto porcentaje de polen de P. foetida y visitan flores en fase 1 y 2; pueden ser considerados los principales polinizadores. Pseudaugochloropsis sp. (Halictidae raramente contactan las anteras o los estigmas cuando perforan el limen para acceder al néctar y visitan flores en fase 2 y 3; son ladrones de néctar que raramente polinizan. Augochlorella sp. (Halictidae recolectan polen sin tocar los estigmas y visitan flores en fase 2 y 3; son hurtadores de polen.A reproductive experiment shows that Passiflora foetida is autocompatible. Observations of floral characteristics and visitors during anthesis, plus the analysis of pollen allowed identification of floral syndrome (melittophily and functions for each visitor. Anthesis occurs from 6 to 11 AM. Three floral phases were identified: 1 stigmas above anthers, 2 stigmas at anther level, 3 stigmas above anthers; radii, petals and sepals become incurved. The stigmas are receptive during the
Our previous study indicated that the tiger lily (Lilium lancifolium var. Flore Pleno) has a great ability to produce inflorescence bulbils in nature as a form of natural phenomenon of floral reversion in plants. This present research was carried out to investigate the artificial floral reversion in in vitro culture of two lilies (Asiatic ...
Nov 2, 2016 ... Our previous study indicated that the tiger lily (Lilium lancifolium var. Flore Pleno) has a great ability to produce inflorescence bulbils in nature as a form of natural phenomenon of floral reversion in plants. This present research was carried out to investigate the artificial floral reversion in in vitro culture of.
Full Text Available floral ontogeny also given. Air. J. 801. 1983,2:202?208 I Beskrywing van die blomdele word gegee. Die helrnknop ord gekenmerk deur die prominente olieklier op die punt van ie helmbindsel. Die saadhuid van die vrugbare en steriele aadknop verskil.... Slegs die epidermis van die buitenste en bin este integumente bly in die saadhuid behoue. ?n Kort eskrywing van die bearing van die blom en sy ontogenie word ok gegee. -Air. Tydskr. Pianik. 1983,2:202?208 eywords: Leptospermum Iaevigatum, flower...
Bartoš, Michael; Janeček, Stěpán
Specific pollen placement by zygomorphic flowers on pollinators is one of the key innovations of angiosperm evolution . In most phylogenetic lineages that have evolved zygomorphic flowers, reproductive organs are positioned either in the lower or upper part of the flower. Although these specific positions largely enhance pollen economy, they also represent architectural constraints such that flowers are able to place pollen only on the dorsal or ventral part of pollinators' bodies . Such constraints can lead to interspecific pollen placement in situations where phylogenetically related species with the same floral architecture share pollinators . Copyright © 2014 Elsevier Ltd. All rights reserved.
Smith, Harley M S; Ung, Nolan; Lal, Shruti; Courtier, Jennifer
In Arabidopsis floral meristems are specified on the periphery of the inflorescence meristem by the combined activities of the FLOWERING LOCUS T (FT)-FD complex and the flower meristem identity gene LEAFY. The floral specification activity of FT is dependent upon two related BELL1-like homeobox (BLH) genes PENNYWISE (PNY) and POUND-FOOLISH (PNF) which are required for floral evocation. PNY and PNF interact with a subset of KNOTTED1-LIKE homeobox proteins including SHOOT MERISTEMLESS (STM). Genetic analyses show that these BLH proteins function with STM to specify flowers and internodes during inflorescence development. In this study, experimental evidence demonstrates that the specification of flower and coflorescence meristems requires the combined activities of FT-FD and STM. FT and FD also regulate meristem maintenance during inflorescence development. In plants with reduced STM function, ectopic FT and FD promote the formation of axillary meristems during inflorescence development. Lastly, gene expression studies indicate that STM functions with FT-FD and AGAMOUS-LIKE 24 (AGL24)-SUPPRESSOR OF OVEREXPRESSION OF CONTANS1 (SOC1) complexes to up-regulate flower meristem identity genes during inflorescence development.
Wang, Xiaoyan; Zhang, Xuemei; Zhao, Lei; Guo, Zhenhua
The mechanism of floral transition in bamboo remains unclear. Dendrocalamus latiflorus (Bambusease, Bambusoideae, Poaceae) is an economically and ecologically important clumping bamboo in tropical and subtropical areas. We evaluated morphological characteristics and gene expression profiling to study floral induction and early flower development in D. latiflorus. The detailed morphological studies on vegetative buds and floral organography were completed using paraffin sectioning and scanning...
Jun Hyung Lee; Paula M. Pijut
Reproductive sterility, which can be obtained by manipulating floral organ identity genes, is an important tool for gene containment of genetically engineered trees. In Arabidopsis, AGAMOUS (AG) is the only C-class gene responsible for both floral meristem determinacy and floral organ identity, and its mutations produce...
Margeris Yanes Calderón
Full Text Available Se realizó un trabajo dirigido a los Médicos de Familia sobre la aplicación de los remedios (esencias, elíxires florales de Bach durante la etapa climatérica. Se describen los 5 elíxires florales que han tenido mayor indicación en la consulta de climaterio del Policlínico Docente "Ana Betancourt," en el municipio Playa de la Ciudad de La Habana, así como su forma de preparación y administración. Se citan algunas esencias florales de nueva generación, que por su vibración y calidad podrían indicarse en esta etapa de la vida femenina. En aquellas mujeres de edad mediana (climatéricas, donde predominen los síntomas psicológicos sobre los circulatorios, genitourinarios y generales, la terapia floral se impone como una alternativa de tratamiento para mejorar su calidad de vida.A paper directed to the family physicians on the application of Bach's floral remedies (essence oils and elixirs during the climateric period was made. The 5 floral elixirs that have been prescribed the most at the climacteric office of "Ana Betancourt" Teaching Polyclinic, in Playa municipality, Havana City, as well as their mode of preparation and administration are described. Some new generation floral essences that due to their vibration and quality may be indicated at this stage of females' life, are mentioned. In those middle-aged women (climacteric among whom the psychological symptoms prevailed over the circulatory, genitourinary and general symptoms, the floral therapy constitutes an alternative treatment to improve their quality of life.
Wang, Yong-Qiang; Melzer, Rainer; Theissen, Günter
Several lines of evidence suggest that the identity of floral organs in angiosperms is specified by multimeric transcription factor complexes composed of MADS-domain proteins. These bind to specific cis-regulatory elements ('CArG-boxes') of their target genes involving DNA-loop formation, thus constituting 'floral quartets'. Gymnosperms, angiosperms' closest relatives, contain orthologues of floral homeotic genes, but when and how the interactions constituting floral quartets were established during evolution has remained unknown. We have comprehensively studied the dimerization and DNA-binding of several classes of MADS-domain proteins from the gymnosperm Gnetum gnemon. Determination of protein-protein and protein-DNA interactions by yeast two-hybrid, in vitro pull-down and electrophoretic mobility shift assays revealed complex patterns of homo- and heterodimerization among orthologues of floral homeotic class B, class C and class E proteins and B(sister) proteins. Using DNase I footprint assays we demonstrate that both orthologues of class B with C proteins, and orthologues of class C proteins alone, but not orthologues of class B proteins alone can loop DNA in floral quartet-like complexes. This is in contrast to class B and class C proteins from angiosperms, which require other factors such as class E floral homeotic proteins to 'glue' them together in multimeric complexes. Our findings suggest that the evolutionary origin of floral quartet formation is based on the interaction of different DNA-bound homodimers, does not depend on class E proteins, and predates the origin of angiosperms. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd.
O'Maoiléidigh, Diarmuid Seosamh; Wellmer, Frank
Assessing the molecular changes that occur over the course of flower development is hampered by difficulties in isolating sufficient amounts of floral tissue at specific developmental stages. This is especially problematic when investigating molecular events at very early stages of Arabidopsis flower development, as the floral buds are minute and are initiated sequentially such that a single flower on an inflorescence is at a given developmental stage. Moreover, young floral buds are hidden by older buds, which present an additional challenge for dissection. To circumvent these issues, a floral induction system that allows the simultaneous induction of a large number of flowers on the inflorescence of a single plant was generated. To allow the plant community to avail of the full benefits of this system, we address some common problems that can be encountered when growing these plants and collecting floral buds for analysis.
Full Text Available Angiosperm flowers are usually determinate structures that may produce seeds. In some species, flowers can revert from committed flower development back to an earlier developmental phase in a process called floral reversion. The allopolyploid Arabidopsis suecica displays photoperiod-dependent floral reversion in a subset of its flowers, yet little is known about the environmental conditions enhancing this phenotype, or the morphological processes leading to reversion. We have used light and electron microscopy to further describe this phenomenon. Additionally, we have further studied the phenology of flowering and floral reversion in A. suecica. In this study we confirm and expand upon our previous findings that floral reversion in the allopolyploid A. suecica is photoperiod-dependent, and show that its frequency is correlated with the timing for the onset of flowering. Our results also suggest that floral reversion in A. suecica displays natural variation in its penetrance between geographic populations of A. suecica.
Schiestl, Florian P
Floral volatiles are complex, multi-functional signals that are often used by pollinators in combination with other signals, such as color. Floral visitors use floral scent to estimate the amount of reward present in flowers, to facilitate the identification of a specific host flower or as signals that chemically resemble those important for pollinator insects in other ecological contexts. There is good evidence that floral scent evolves under selection imposed by both mutualists and antagonists. Antagonists may often limit the amount of scent emitted by flowers, thus contributing to spatial population variation, and select for phenotypic plasticity after enemy attack. Floral scent is also an important component of pollinator-mediated reproductive isolation, as it often co-varies with color and morphology in sister species with different pollination systems. © 2015 The Author. New Phytologist © 2015 New Phytologist Trust.
Mahesh Chandra Patra
Full Text Available The toll/interleukin 1 receptor (TIR domain-containing adaptor protein (TIRAP plays an important role in the toll-like receptor (TLR 2, TLR4, TLR7, and TLR9 signaling pathways. TIRAP anchors to phosphatidylinositol (PI 4,5-bisphosphate (PIP2 on the plasma membrane and PI (3,4,5-trisphosphate (PIP3 on the endosomal membrane and assists in recruitment of the myeloid differentiation primary response 88 protein to activated TLRs. To date, the structure and mechanism of TIRAP’s membrane association are only partially understood. Here, we modeled an all-residue TIRAP dimer using homology modeling, threading, and protein–protein docking strategies. Molecular dynamics simulations revealed that PIP2 creates a stable microdomain in a dipalmitoylphosphatidylcholine bilayer, providing TIRAP with its physiologically relevant orientation. Computed binding free energy values suggest that the affinity of PI-binding domain (PBD for PIP2 is stronger than that of TIRAP as a whole for PIP2 and that the short PI-binding motif (PBM contributes to the affinity between PBD and PIP2. Four PIP2 molecules can be accommodated by distinct lysine-rich surfaces on the dimeric PBM. Along with the known PI-binding residues (K15, K16, K31, and K32, additional positively charged residues (K34, K35, and R36 showed strong affinity toward PIP2. Lysine-to-alanine mutations at the PI-binding residues abolished TIRAP’s affinity for PIP2; however, K34, K35, and R36 consistently interacted with PIP2 headgroups through hydrogen bond (H-bond and electrostatic interactions. TIRAP exhibited a PIP2-analogous intermolecular contact and binding affinity toward PIP3, aided by an H-bond network involving K34, K35, and R36. The present study extends our understanding of TIRAP’s membrane association, which could be helpful in designing peptide decoys to block TLR2-, TLR4-, TLR7-, and TLR9-mediated autoimmune diseases.
Angibaud, Julie; Baudouin, Stéphane J; Louveau, Antoine; Nerrière-Daguin, Véronique; Bonnamain, Virginie; Csaba, Zsolt; Dournaud, Pascal; Naveilhan, Philippe; Noraz, Nelly; Pellier-Monnin, Véronique; Boudin, Hélène
Immune signaling and neuroinflammatory mediators have recently emerged as influential variables that regulate neural precursor/stem cell (NPC) behavior and function. In this study, we investigated whether the signaling adaptor protein CD3ζ, a transmembrane protein involved in T cell differentiation and function and recently shown to regulate neuronal development in the central nervous system (CNS), may have a role in NPC differentiation. We analyzed the expression profile of CD3ζ in embryonic rat brain during neurogenic periods and in neurosphere-derived neural cells, and we investigated the action of CD3ζ on cell differentiation. We found that CD3ζ expression coincided with neuronal commitment, but its forced expression in NPCs prevented the production of neurons and oligodendrocytes, but not astroglial cells. This blockade of neuronal differentiation was operated through an ITAM-independent mechanism, but required the Asp36 of the CD3ζ transmembrane domain involved in membrane receptor interaction. Together, our findings show that ectopic CD3ζ expression in NPCs impaired their normal cell-fate specification and suggest that variations of CD3ζ expression in the developing CNS might result in neurodevelopmental anomalies.
Wessinger, Carolyn A; Hileman, Lena C; Rausher, Mark D
Distinct floral pollination syndromes have emerged multiple times during the diversification of flowering plants. For example, in western North America, a hummingbird pollination syndrome has evolved more than 100 times, generally from within insect-pollinated lineages. The hummingbird syndrome is characterized by a suite of floral traits that attracts and facilitates pollen movement by hummingbirds, while at the same time discourages bee visitation. These floral traits generally include large nectar volume, red flower colour, elongated and narrow corolla tubes and reproductive organs that are exerted from the corolla. A handful of studies have examined the genetic architecture of hummingbird pollination syndrome evolution. These studies find that mutations of relatively large effect often explain increased nectar volume and transition to red flower colour. In addition, they suggest that adaptive suites of floral traits may often exhibit a high degree of genetic linkage, which could facilitate their fixation during pollination syndrome evolution. Here, we explore these emerging generalities by investigating the genetic basis of floral pollination syndrome divergence between two related Penstemon species with different pollination syndromes--bee-pollinated P. neomexicanus and closely related hummingbird-pollinated P. barbatus. In an F2 mapping population derived from a cross between these two species, we characterized the effect size of genetic loci underlying floral trait divergence associated with the transition to bird pollination, as well as correlation structure of floral trait variation. We find the effect sizes of quantitative trait loci for adaptive floral traits are in line with patterns observed in previous studies, and find strong evidence that suites of floral traits are genetically linked. This linkage may be due to genetic proximity or pleiotropic effects of single causative loci. Interestingly, our data suggest that the evolution of floral traits
McCarthy, Elizabeth W; Arnold, Sarah E J; Chittka, Lars; Le Comber, Steven C; Verity, Robert; Dodsworth, Steven; Knapp, Sandra; Kelly, Laura J; Chase, Mark W; Baldwin, Ian T; Kovařík, Aleš; Mhiri, Corinne; Taylor, Lin; Leitch, Andrew R
Speciation in angiosperms can be accompanied by changes in floral colour that may influence pollinator preference and reproductive isolation. This study investigates whether changes in floral colour can accompany polyploid and homoploid hybridization, important processes in angiosperm evolution. Spectral reflectance of corolla tissue was examined for 60 Nicotiana (Solanaceae) accessions (41 taxa) based on spectral shape (corresponding to pigmentation) as well as bee and hummingbird colour perception in order to assess patterns of floral colour evolution. Polyploid and homoploid hybrid spectra were compared with those of their progenitors to evaluate whether hybridization has resulted in floral colour shifts. Floral colour categories in Nicotiana seem to have arisen multiple times independently during the evolution of the genus. Most younger polyploids displayed an unexpected floral colour, considering those of their progenitors, in the colour perception of at least one pollinator type, whereas older polyploids tended to resemble one or both of their progenitors. Floral colour evolution in Nicotiana is weakly constrained by phylogeny, and colour shifts do occur in association with both polyploid and homoploid hybrid divergence. Transgressive floral colour in N. tabacum has arisen by inheritance of anthocyanin pigmentation from its paternal progenitor while having a plastid phenotype like its maternal progenitor. Potentially, floral colour evolution has been driven by, or resulted in, pollinator shifts. However, those polyploids that are not sympatric (on a regional scale) with their progenitor lineages are typically not divergent in floral colour from them, perhaps because of a lack of competition for pollinators. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Campbell, Diane R; Powers, John M
Climate has the potential to influence evolution, but how it influences the strength or direction of natural selection is largely unknown. We quantified the strength of selection on four floral traits of the subalpine herb Ipomopsis sp. in 10 years that differed in precipitation, causing extreme temporal variation in the date of snowmelt in the Colorado Rocky Mountains. The chosen floral traits were under selection by hummingbird and hawkmoth pollinators, with hawkmoth abundance highly variable across years. Selection for flower length showed environmental sensitivity, with stronger selection in years with later snowmelt, as higher water resources can allow translation of pollination success into fitness based on seed production. Selection on corolla width also varied across years, favouring narrower corolla tubes in two unusual years with hawkmoths, and wider corollas in another late snowmelt year. Our results illustrate how changes in climate could alter natural selection even when the primary selective agent is not directly influenced. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Chuan He Liu
-seq and gene expression profiling results. Ethephon-mediated induction likely mimics the process of vernalization in the floral transition in pineapple by increasing LTI, FT and VRN1 expression and promoting the up-regulation of floral meristem identity genes involved in flower development. The candidate genes screened can be used in investigations of the molecular mechanisms of the flowering pathway and of various other biological mechanisms in pineapple.
Savada, Raghavendra P; Ozga, Jocelyn A; Jayasinghege, Charitha P A; Waduthanthri, Kosala D; Reinecke, Dennis M
Ethylene biosynthesis is regulated in reproductive tissues in response to heat stress in a manner to optimize resource allocation to pollinated fruits with developing seeds. High temperatures during reproductive development are particularly detrimental to crop fruit/seed production. Ethylene plays vital roles in plant development and abiotic stress responses; however, little is known about ethylene's role in reproductive tissues during development under heat stress. We assessed ethylene biosynthesis and signaling regulation within the reproductive and associated tissues of pea during the developmental phase that sets the stage for fruit-set and seed development under normal and heat-stress conditions. The transcript abundance profiles of PsACS [encode enzymes that convert S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylic acid (ACC)] and PsACO (encode enzymes that convert ACC to ethylene), and ethylene evolution were developmentally, environmentally, and tissue-specifically regulated in the floral/fruit/pedicel tissues of pea. Higher transcript abundance of PsACS and PsACO in the ovaries, and PsACO in the pedicels was correlated with higher ethylene evolution and ovary senescence and pedicel abscission in fruits that were not pollinated under control temperature conditions. Under heat-stress conditions, up-regulation of ethylene biosynthesis gene expression in pre-pollinated ovaries was also associated with higher ethylene evolution and lower retention of these fruits. Following successful pollination and ovule fertilization, heat-stress modified PsACS and PsACO transcript profiles in a manner that suppressed ovary ethylene evolution. The normal ethylene burst in the stigma/style and petals following pollination was also suppressed by heat-stress. Transcript abundance profiles of ethylene receptor and signaling-related genes acted as qualitative markers of tissue ethylene signaling events. These data support the hypothesis that ethylene biosynthesis is
Ajay Konapala, Mr.; Koona, Ramji, Dr.
Information systems play a key role in the modern era of Information Technology. Rapid developments in IT & global competition calls for many changes in basic CAD/CAM/CAPP/CNC manufacturing chain of operations. ‘STEP-NC’ an enhancement to STEP for operating CNC machines, creating new opportunities for collaborative, concurrent, adaptive works across the manufacturing chain of operations. Schemas and data models defined by ISO14649 in liaison with ISO10303 standards made STEP-NC file rich with feature based, rather than mere point to point information of G/M Code format. But one needs to have a suitable information system to understand and modify these files. Various STEP-NC information systems are reviewed to understand the suitability of STEP-NC for web manufacturing. Present work also deals with the development of an adaptor which imports STEP-NC file, organizes its information, allowing modifications to entity values and finally generates a new STEP-NC file to export. The system is designed and developed to work on web to avail additional benefits through the web and also to be part of a proposed ‘Web based STEP-NC manufacturing platform’ which is under development and explained as future scope.
Miller, Sharon E; Sahlender, Daniela A; Graham, Stephen C; Höning, Stefan; Robinson, Margaret S; Peden, Andrew A; Owen, David J
SNAREs provide a large part of the specificity and energy needed for membrane fusion and, to do so, must be localized to their correct membranes. Here, we show that the R-SNAREs VAMP8, VAMP3, and VAMP2, which cycle between the plasma membrane and endosomes, bind directly to the ubiquitously expressed, PtdIns4,5P(2)-binding, endocytic clathrin adaptor CALM/PICALM. X-ray crystallography shows that the N-terminal halves of their SNARE motifs bind the CALM(ANTH) domain as helices in a manner that mimics SNARE complex formation. Mutation of residues in the CALM:SNARE interface inhibits binding in vitro and prevents R-SNARE endocytosis in vivo. Thus, CALM:R-SNARE interactions ensure that R-SNAREs, required for the fusion of endocytic clathrin-coated vesicles with endosomes and also for subsequent postendosomal trafficking, are sorted into endocytic vesicles. CALM's role in directing the endocytosis of small R-SNAREs may provide insight into the association of CALM/PICALM mutations with growth retardation, cognitive defects, and Alzheimer's disease. Copyright © 2011 Elsevier Inc. All rights reserved.
Full Text Available The AP-5 adaptor protein complex is presumed to function in membrane traffic, but so far nothing is known about its pathway or its cargo. We have used CRISPR-Cas9 to knock out the AP-5 ζ subunit gene, AP5Z1, in HeLa cells, and then analysed the phenotype by subcellular fractionation profiling and quantitative mass spectrometry. The retromer complex had an altered steady-state distribution in the knockout cells, and several Golgi proteins, including GOLIM4 and GOLM1, were depleted from vesicle-enriched fractions. Immunolocalisation showed that loss of AP-5 led to impaired retrieval of the cation-independent mannose 6-phosphate receptor (CIMPR, GOLIM4, and GOLM1 from endosomes back to the Golgi region. Knocking down the retromer complex exacerbated this phenotype. Both the CIMPR and sortilin interacted with the AP-5-associated protein SPG15 in pull-down assays, and we propose that sortilin may act as a link between Golgi proteins and the AP-5/SPG11/SPG15 complex. Together, our findings suggest that AP-5 functions in a novel sorting step out of late endosomes, acting as a backup pathway for retromer. This provides a mechanistic explanation for why mutations in AP-5/SPG11/SPG15 cause cells to accumulate aberrant endolysosomes, and highlights the role of endosome/lysosome dysfunction in the pathology of hereditary spastic paraplegia and other neurodegenerative disorders.
Full Text Available Dengue is one of the most important arboviral diseases caused by infection of four serotypes of dengue virus (DEN. We found that activation of interferon regulatory factor 3 (IRF3 triggered by viral infection and by foreign DNA and RNA stimulation was blocked by DEN-encoded NS2B3 through a protease-dependent mechanism. The key adaptor protein in type I interferon pathway, human mediator of IRF3 activation (MITA but not the murine homologue MPYS, was cleaved in cells infected with DEN-1 or DEN-2 and with expression of the enzymatically active protease NS2B3. The cleavage site of MITA was mapped to LRR↓(96G and the function of MITA was suppressed by dengue protease. DEN replication was reduced with overexpression of MPYS but not with MITA, while DEN replication was enhanced by MPYS knockdown, indicating an antiviral role of MITA/MPYS against DEN infection. The involvement of MITA in DEN-triggered innate immune response was evidenced by reduction of IRF3 activation and IFN induction in cells with MITA knockdown upon DEN-2 infection. NS2B3 physically interacted with MITA, and the interaction and cleavage of MITA could be further enhanced by poly(dA:dT stimulation. Thus, we identified MITA as a novel host target of DEN protease and provide the molecular mechanism of how DEN subverts the host innate immunity.
Das, Rupali; Bassiri, Hamid; Guan, Peng; Wiener, Susan; Banerjee, Pinaki P; Zhong, Ming-Chao; Veillette, André; Orange, Jordan S; Nichols, Kim E
The adaptor molecule signaling lymphocytic activation molecule-associated protein (SAP) plays critical roles during invariant natural killer T (iNKT) cell ontogeny. As a result, SAP-deficient humans and mice lack iNKT cells. The strict developmental requirement for SAP has made it difficult to discern its possible involvement in mature iNKT cell functions. By using temporal Cre recombinase-mediated gene deletion to ablate SAP expression after completion of iNKT cell development, we demonstrate that SAP is essential for T-cell receptor (TCR)-induced iNKT cell cytotoxicity against T-cell and B-cell leukemia targets in vitro and iNKT-cell-mediated control of T-cell leukemia growth in vivo. These findings are not restricted to the murine system: silencing RNA-mediated suppression of SAP expression in human iNKT cells also significantly impairs TCR-induced cytolysis. Mechanistic studies reveal that iNKT cell killing requires the tyrosine kinase Fyn, a known SAP-binding protein. Furthermore, SAP expression is required within iNKT cells to facilitate their interaction with T-cell targets and induce reorientation of the microtubule-organizing center to the immunologic synapse (IS). Collectively, these studies highlight a novel and essential role for SAP during iNKT cell cytotoxicity and formation of a functional IS.
Lavin, Martin F; Kozlov, Sergei; Gatei, Magtouf; Kijas, Amanda W
The recognition, signalling and repair of DNA double strand breaks (DSB) involves the participation of a multitude of proteins and post-translational events that ensure maintenance of genome integrity. Amongst the proteins involved are several which when mutated give rise to genetic disorders characterised by chromosomal abnormalities, cancer predisposition, neurodegeneration and other pathologies. ATM (mutated in ataxia-telangiectasia (A-T) and members of the Mre11/Rad50/Nbs1 (MRN complex) play key roles in this process. The MRN complex rapidly recognises and locates to DNA DSB where it acts to recruit and assist in ATM activation. ATM, in the company of several other DNA damage response proteins, in turn phosphorylates all three members of the MRN complex to initiate downstream signalling. While ATM has hundreds of substrates, members of the MRN complex play a pivotal role in mediating the downstream signalling events that give rise to cell cycle control, DNA repair and ultimately cell survival or apoptosis. Here we focus on the interplay between ATM and the MRN complex in initiating signaling of breaks and more specifically on the adaptor role of the MRN complex in mediating ATM signalling to downstream substrates to control different cellular processes.
Full Text Available Canine hepacivirus (CHV was recently identified in domestic dogs and horses. The finding that CHV is genetically the virus most closely related to hepatitis C virus (HCV has raised the question of whether HCV might have evolved as the result of close contact between dogs and/or horses and humans. The aim of this study was to investigate whether the NS3/4A serine protease of CHV specifically cleaves human mitochondrial antiviral signaling protein (MAVS and Toll-IL-1 receptor domain-containing adaptor inducing interferon-beta (TRIF. The proteolytic activity of CHV NS3/4A was evaluated using a bacteriophage lambda genetic screen. Human MAVS- and TRIF-specific cleavage sites were engineered into the lambda cI repressor. Upon infection of Escherichia coli cells coexpressing these repressors and a CHV NS3/4A construct, lambda phage replicated up to 2000-fold more efficiently than in cells expressing a CHV protease variant carrying the inactivating substitution S139A. Comparable results were obtained when several HCV NS3/4A constructs of genotype 1b were assayed. This indicates that CHV can disrupt the human innate antiviral defense signaling pathway and suggests a possible evolutionary relationship between CHV and HCV.
Full Text Available Abstract Background Evolution of unisexual flowers entails one of the most extreme changes in plant development. Cultivated spinach, Spinacia oleracea L., is uniquely suited for the study of unisexual flower development as it is dioecious and it achieves unisexually by the absence of organ development, rather than by organ abortion or suppression. Male staminate flowers lack fourth whorl primordia and female pistillate flowers lack third whorl primordia. Based on theoretical considerations, early inflorescence or floral organ identity genes would likely be directly involved in sex-determination in those species in which organ initiation rather than organ maturation is regulated. In this study, we tested the hypothesis that sexual dimorphism occurs through the regulation of B class floral organ gene expression by experimentally knocking down gene expression by viral induced gene silencing. Results Suppression of B class genes in spinach resulted in the expected homeotic transformation of stamens into carpels but also affected the number of perianth parts and the presence of fourth whorl. Phenotypically normal female flowers developed on SpPI-silenced male plants. Suppression of the spinach C class floral organ identity gene, SpAG, resulted in loss of reproductive organ identity, and indeterminate flowers, but did not result in additional sex-specific characteristics or structures. Analysis of the genomic sequences of both SpAP3 and SpPI did not reveal any allelic differences between males and females. Conclusion Sexual dimorphism in spinach is not the result of homeotic transformation of established organs, but rather is the result of differential initiation and development of the third and fourth whorl primordia. SpAG is inferred to have organ identity and meristem termination functions similar to other angiosperm C class genes. In contrast, while SpPI and SpAP3 resemble other angiosperms in their essential functions in establishing stamen
Background Evolution of unisexual flowers entails one of the most extreme changes in plant development. Cultivated spinach, Spinacia oleracea L., is uniquely suited for the study of unisexual flower development as it is dioecious and it achieves unisexually by the absence of organ development, rather than by organ abortion or suppression. Male staminate flowers lack fourth whorl primordia and female pistillate flowers lack third whorl primordia. Based on theoretical considerations, early inflorescence or floral organ identity genes would likely be directly involved in sex-determination in those species in which organ initiation rather than organ maturation is regulated. In this study, we tested the hypothesis that sexual dimorphism occurs through the regulation of B class floral organ gene expression by experimentally knocking down gene expression by viral induced gene silencing. Results Suppression of B class genes in spinach resulted in the expected homeotic transformation of stamens into carpels but also affected the number of perianth parts and the presence of fourth whorl. Phenotypically normal female flowers developed on SpPI-silenced male plants. Suppression of the spinach C class floral organ identity gene, SpAG, resulted in loss of reproductive organ identity, and indeterminate flowers, but did not result in additional sex-specific characteristics or structures. Analysis of the genomic sequences of both SpAP3 and SpPI did not reveal any allelic differences between males and females. Conclusion Sexual dimorphism in spinach is not the result of homeotic transformation of established organs, but rather is the result of differential initiation and development of the third and fourth whorl primordia. SpAG is inferred to have organ identity and meristem termination functions similar to other angiosperm C class genes. In contrast, while SpPI and SpAP3 resemble other angiosperms in their essential functions in establishing stamen identity, they also appear to have
Pareja, Martin; Qvarfordt, Erika; Webster, Ben; Mayon, Patrick; Pickett, John; Birkett, Michael; Glinwood, Robert
There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.
Pattamayutanon, Praetinee; Angeli, Sergio; Thakeow, Prodpran; Abraham, John; Disayathanoowat, Terd; Chantawannakul, Panuwan
The volatile organic compounds (VOCs) of four monofloral and one multifloral of Thai honeys produced by Apis cerana, Apis dorsata and Apis mellifera were analyzed by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography and mass spectrometry (GC-MS). The floral sources were longan, sunflower, coffee, wild flowers (wild) and lychee. Honey originating from longan had more VOCs than all other floral sources. Sunflower honey had the least numbers of VOCs. cis-Linalool oxide, trans-linalool oxide, ho-trienol, and furan-2,5-dicarbaldehyde were present in all the honeys studied, independent of their floral origin. Interestingly, 2-phenylacetaldehyde was detected in all honey sample except longan honey produced by A. cerana. Thirty-two VOCs were identified as possible floral markers. After validating differences in honey volatiles from different floral sources and honeybee species, the results suggest that differences in quality and quantity of honey volatiles are influenced by both floral source and honeybee species. The group of honey volatiles detected from A. cerana was completely different from those of A. mellifera and A. dorsata. VOCs could therefore be applied as chemical markers of honeys and may reflect preferences of shared floral sources amongst different honeybee species.
Full Text Available There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.
Jacquemyn, Hans; Lenaerts, Marijke; Tyteca, Daniel; Lievens, Bart
Abstract Floral nectar of animal-pollinated plants is commonly infested with microorganisms, yet little is known about the microorganisms inhabiting the floral nectar of orchids. In this study, we investigated microbial communities occurring in the floral nectar of seven Epipactis (Orchidaceae) species. Culturable bacteria and yeasts were isolated and identified by partially sequencing the small subunit (SSU) ribosomal RNA (rRNA) gene and the D1/D2 domains of the large subunit (LSU) rRNA gene, respectively. Using three different culture media, we found that bacteria were common inhabitants of the floral nectar of Epipactis. The most widely distributed bacterial operational taxonomic units (OTUs) in nectar of Epipactis were representatives of the family of Enterobacteriaceae, with an unspecified Enterobacteriaceae bacterium as the most common. In contrast to previous studies investigating microbial communities in floral nectar, very few yeast species (mainly of the genus Cryptococcus) were observed, and most of them occurred in very low densities. Total OTU richness (i.e., the number of bacterial and yeast OTUs per orchid species) varied between 4 and 20. Cluster analysis revealed that microbial communities of allogamous species differed from those of autogamous and facultatively autogamous species. This study extends previous efforts to identify microbial communities in floral nectar and indicates that the floral nectar of the orchids investigated mainly contained bacterial communities with moderate phylogenetic diversity. PMID:23836678
Papadopulos, Alexander S T; Powell, Martyn P; Pupulin, Franco; Warner, Jorge; Hawkins, Julie A; Salamin, Nicolas; Chittka, Lars; Williams, Norris H; Whitten, W Mark; Loader, Deniz; Valente, Luis M; Chase, Mark W; Savolainen, Vincent
The great majority of plant species in the tropics require animals to achieve pollination, but the exact role of floral signals in attraction of animal pollinators is often debated. Many plants provide a floral reward to attract a guild of pollinators, and it has been proposed that floral signals of non-rewarding species may converge on those of rewarding species to exploit the relationship of the latter with their pollinators. In the orchid family (Orchidaceae), pollination is almost universally animal-mediated, but a third of species provide no floral reward, which suggests that deceptive pollination mechanisms are prevalent. Here, we examine floral colour and shape convergence in Neotropical plant communities, focusing on certain food-deceptive Oncidiinae orchids (e.g. Trichocentrum ascendens and Oncidium nebulosum) and rewarding species of Malpighiaceae. We show that the species from these two distantly related families are often more similar in floral colour and shape than expected by chance and propose that a system of multifarious floral mimicry--a form of Batesian mimicry that involves multiple models and is more complex than a simple one model-one mimic system--operates in these orchids. The same mimetic pollination system has evolved at least 14 times within the species-rich Oncidiinae throughout the Neotropics. These results help explain the extraordinary diversification of Neotropical orchids and highlight the complexity of plant-animal interactions.
Singh, Archana; Ansari, Mohammad W; Rani, Varsha; Singh, C P; Shukla, Alok; Pant, Ramesh C; Tuteja, Narendra; Bains, Gurdeep
Floral malformation is the most destructive disease in mangoes. To date, the etiology of this disease has not been resolved. There are indications that stress-stimulated ethylene production might be responsible for the disease. Putrescine mediates various physiological processes for normal functioning and cellular metabolism. Here, the effect of putrescine in concentration ranging from 10(-1) to 10(-3) M was evaluated on disease incidence during mango flowering seasons of 2012 and 2013. In a scanning electron microscopy (SEM) study, putrescine (10(-2) M)-treated malformed floral buds bloomed into opened flowers with separated sepals and/or petals like healthy, whereas the untreated (control) malformed buds remained deformed. Further, malformed flowers recovered upon putrescine treatment, displaying clearly bilobed anthers, enclosing a large number of normal pollen grains and functional ovary with broad stigmatic surface as compared to control. The present findings provide the first report to demonstrate the role of putrescine in reducing various adverse effects of stress ethylene via decelerating the higher pace of its biosynthesis. It stabilizes the normal morphology, development, and functions of malformed reproductive organs to facilitate successful pollination, fertilization, and, thereby, fruit set in mango flowers. However, putrescine-ethylene-mediated cell signaling network, involving various genes to trigger the response, which regulates a wide range of developmental and physiological processes leading to normal cell physiology, needs to be investigated further.
Stitz, Michael; Hartl, Markus; Baldwin, Ian T; Gaquerel, Emmanuel
Jasmonic acid and its derivatives (jasmonates [JAs]) play central roles in floral development and maturation. The binding of jasmonoyl-L-isoleucine (JA-Ile) to the F-box of CORONATINE INSENSITIVE1 (COI1) is required for many JA-dependent physiological responses, but its role in anthesis and pollinator attraction traits remains largely unexplored. Here, we used the wild tobacco Nicotiana attenuata, which develops sympetalous flowers with complex pollination biology, to examine the coordinating function of JA homeostasis in the distinct metabolic processes that underlie flower maturation, opening, and advertisement to pollinators. From combined transcriptomic, targeted metabolic, and allometric analyses of transgenic N. attenuata plants for which signaling deficiencies were complemented with methyl jasmonate, JA-Ile, and its functional homolog, coronatine (COR), we demonstrate that (1) JA-Ile/COR-based signaling regulates corolla limb opening and a JA-negative feedback loop; (2) production of floral volatiles (night emissions of benzylacetone) and nectar requires JA-Ile/COR perception through COI1; and (3) limb expansion involves JA-Ile-induced changes in limb fresh mass and carbohydrate metabolism. These findings demonstrate a master regulatory function of the JA-Ile/COI1 duet for the main function of a sympetalous corolla, that of advertising for and rewarding pollinator services. Flower opening, by contrast, requires JA-Ile signaling-dependent changes in primary metabolism, which are not compromised in the COI1-silenced RNA interference line used in this study. © 2014 American Society of Plant Biologists. All rights reserved.
Farré-Armengol, Gerard; Filella, Iolanda; Llusià, Joan; Niinemets, Ulo; Peñuelas, Josep
We addressed the potential effects of changes in ambient temperature on the profiles of volatile emissions from flowers and tested whether warming could induce significant quantitative and qualitative changes in floral emissions, which would potentially interfere with plant-pollinator chemical communication. We measured the temperature responses of floral emissions of various common species of Mediterranean plants using dynamic headspace sampling and used GC-MS to identify and quantify the emitted terpenes. Floral emissions increased with temperature to an optimum and thereafter decreased. The responses to temperature modeled here predicted increases in the rates of floral terpene emission of 0.03-1.4-fold, depending on the species, in response to an increase of 1 °C in the mean global ambient temperature. Under the warmest projections that predict a maximum increase of 5 °C in the mean temperature of Mediterranean climates in the Northern Hemisphere by the end of the century, our models predicted increases in the rates of floral terpene emissions of 0.34-9.1-fold, depending on the species. The species with the lowest emission rates had the highest relative increases in floral terpene emissions with temperature increases of 1-5 °C. The response of floral emissions to temperature differed among species and among different compounds within the species. Warming not only increased the rates of total emissions, but also changed the ratios among compounds that constituted the floral scents, i.e. increased the signal for pollinators, but also importantly altered the signal fidelity and probability of identification by pollinators, especially for specialists with a strong reliance on species-specific floral blends. © 2014 John Wiley & Sons Ltd.
von Arx, Martin; Goyret, Joaquín; Davidowitz, Goggy; Raguso, Robert A.
Most research on plant–pollinator communication has focused on sensory and behavioral responses to relatively static cues. Floral rewards such as nectar, however, are dynamic, and foraging animals will increase their energetic profit if they can make use of floral cues that more accurately indicate nectar availability. Here we document such a cue—transient humidity gradients—using the night blooming flowers of Oenothera cespitosa (Onagraceae). The headspace of newly opened flowers reaches levels of about 4% above ambient relative humidity due to additive evapotranspirational water loss through petals and water-saturated air from the nectar tube. Floral humidity plumes differ from ambient levels only during the first 30 min after anthesis (before nectar is depleted in wild populations), whereas other floral traits (scent, shape, and color) persist for 12–24 h. Manipulative experiments indicated that floral humidity gradients are mechanistically linked to nectar volume and therefore contain information about energy rewards to floral visitors. Behavioral assays with Hyles lineata (Sphingidae) and artificial flowers with appropriate humidity gradients suggest that these hawkmoth pollinators distinguish between subtle differences in relative humidity when other floral cues are held constant. Moths consistently approached and probed flowers with elevated humidity over those with ambient humidity levels. Because floral humidity gradients are largely produced by the evaporation of nectar itself, they represent condition-informative cues that facilitate remote sensing of floral profitability by discriminating foragers. In a xeric environment, this level of honest communication should be adaptive when plant reproductive success is pollinator limited, due to intense competition for the attention of a specialized pollinator. PMID:22645365
Rivera, Dora I.; Flores, Eugenia M.
Esta es una reinvestigación de la morfología floral de Bixa orellana. Se encontró que varios órganos como androceo y gineceo requerían una descripción nueva. Los estambres tienen anteras dobladas; la dehiscencia es lateral. El ovario es inferior y durante el desarrollo es elevado por un ginoforo. La flor tiene una complicada red de laticíferos y canales gomíferos, en todas las piezas florales. In a reinvestigation of the floral morphology of Bixa orellana, it was found that several organs ...
Full Text Available Phalaenopsis is one of the world’s most popular and important epiphytic monopodial orchids. The extraordinary floral diversity of Phalaenopsis is a reflection of its evolutionary success. As a consequence of this diversity, and of the complexity of flower color development in Phalaenopsis, this species is a valuable research material for developmental biology studies. Nevertheless, research on the molecular mechanisms underlying flower color and floral organ formation in Phalaenopsis is still in the early phases. In this study, we generated large amounts of data from Phalaenopsis flowers by combining Illumina sequencing with differentially expressed gene (DEG analysis. We obtained 37 723 and 34 020 unigenes from petals and labella, respectively. A total of 2736 DEGs were identified, and the functions of many DEGs were annotated by BLAST-searching against several public databases. We mapped 837 up-regulated DEGs (432 from petals and 405 from labella to 102 Kyoto Encyclopedia of Genes and Genomes pathways. Almost all pathways were represented in both petals (102 pathways and labella (99 pathways. DEGs involved in energy metabolism were significantly differentially distributed between labella and petals, and various DEGs related to flower color and floral differentiation were found in the two organs. Interestingly, we also identified genes encoding several key enzymes involved in carotenoid synthesis. These genes were differentially expressed between petals and labella, suggesting that carotenoids may influence Phalaenopsis flower color. We thus conclude that a combination of anthocyanins and/or carotenoids determine flower color formation in Phalaenopsis. These results broaden our understanding of the mechanisms controlling flower color and floral organ differentiation in Phalaenopsis and other orchids.
Full Text Available Obesity and type 2 diabetes are risk factors of Alzheimer's disease (AD. We reported that a high fat diet (HFD promotes amyloid precursor protein (APP cleavage by β-site APP cleaving enzyme 1 (BACE1 without increasing BACE1 levels in APP transgenic mice. However, the detailed mechanism had remained unclear. Here we demonstrate that HFD promotes BACE1/Adaptor protein-2 (AP-2/clathrin complex formation by increasing AP-2 levels in APP transgenic mice. In Swedish APP overexpressing Chinese hamster ovary (CHO cells as well as in SH-SY5Y cells, overexpression of AP-2 promoted the formation of BACE1/AP-2/clathrin complex, increasing the level of the soluble form of APP β (sAPPβ. On the other hand, mutant D495R BACE1, which inhibits formation of this trimeric complex, was shown to decrease the level of sAPPβ. Overexpression of AP-2 promoted the internalization of BACE1 from the cell surface, thus reducing the cell surface BACE1 level. As such, we concluded that HFD may induce the formation of the BACE1/AP-2/clathrin complex, which is followed by its transport of BACE1 from the cell surface to the intracellular compartments. These events might be associated with the enhancement of β-site cleavage of APP in APP transgenic mice. Here we present evidence that HFD, by regulation of subcellular trafficking of BACE1, promotes APP cleavage.
Maesako, Masato; Uemura, Maiko; Tashiro, Yoshitaka; Sasaki, Kazuki; Watanabe, Kiwamu; Noda, Yasuha; Ueda, Karin; Asada-Utsugi, Megumi; Kubota, Masakazu; Okawa, Katsuya; Ihara, Masafumi; Shimohama, Shun; Uemura, Kengo; Kinoshita, Ayae
Obesity and type 2 diabetes are risk factors of Alzheimer's disease (AD). We reported that a high fat diet (HFD) promotes amyloid precursor protein (APP) cleavage by β-site APP cleaving enzyme 1 (BACE1) without increasing BACE1 levels in APP transgenic mice. However, the detailed mechanism had remained unclear. Here we demonstrate that HFD promotes BACE1/Adaptor protein-2 (AP-2)/clathrin complex formation by increasing AP-2 levels in APP transgenic mice. In Swedish APP overexpressing Chinese hamster ovary (CHO) cells as well as in SH-SY5Y cells, overexpression of AP-2 promoted the formation of BACE1/AP-2/clathrin complex, increasing the level of the soluble form of APP β (sAPPβ). On the other hand, mutant D495R BACE1, which inhibits formation of this trimeric complex, was shown to decrease the level of sAPPβ. Overexpression of AP-2 promoted the internalization of BACE1 from the cell surface, thus reducing the cell surface BACE1 level. As such, we concluded that HFD may induce the formation of the BACE1/AP-2/clathrin complex, which is followed by its transport of BACE1 from the cell surface to the intracellular compartments. These events might be associated with the enhancement of β-site cleavage of APP in APP transgenic mice. Here we present evidence that HFD, by regulation of subcellular trafficking of BACE1, promotes APP cleavage.
Enrico De Smaele
Full Text Available Medulloblastoma is the most common pediatric malignant brain tumor, arising from aberrant cerebellar precursors' development, a process mainly controlled by Hedgehog (Hh signaling pathway. Histone deacetylase HDAC1 has been recently shown to modulate Hh signaling, deacetylating its effectors Gli1/2 and enhancing their transcriptional activity. Therefore, HDAC may represent a potential therapeutic target for Hh-dependent tumors, but still little information is available on the physiological mechanisms of HDAC regulation. The putative tumor suppressor RENKCTD11 acts through ubiquitination-dependent degradation of HDAC1, thereby affecting Hh activity and medulloblastoma growth. We identify and characterize here two RENKCTD11 homologues, defining a new family of proteins named KCASH, as “KCTD containing, Cullin3 adaptor, suppressor of Hedgehog.” Indeed, the novel genes (KCASH2KCTD21 and KCASH3KCTD6 share with RENKCTD11 a number of features, such as a BTB domain required for the formation of a Cullin3 ubiquitin ligase complex and HDAC1 ubiquitination and degradation capability, suppressing the acetylation-dependent Hh/Gli signaling. Expression of KCASH2 and -3 is observed in cerebellum, whereas epigenetic silencing and allelic deletion are observed in human medulloblastoma. Rescuing KCASHs expression reduces the Hedgehog-dependent medulloblastoma growth, suggesting that loss of members of this novel family of native HDAC inhibitors is crucial in sustaining Hh pathway-mediated tumorigenesis. Accordingly, they might represent a promising class of endogenous “agents” through which this pathway may be targeted.
Fishman, Michael A; Hadany, Lilach
Flowering plants are a major component of terrestrial ecosystems, and most of them depend on animal pollinators for reproduction. Thus, the mutualism between flowering plants and their pollinators is a keystone ecological relationship in both natural and agricultural ecosystems. Though plant-pollinator interactions have received considerable amount of attention, there are still many unanswered questions. In this paper, we use methods of evolutionary game theory to investigate the co-evolution of floral advertisement and pollinator preferences Our results indicate that competition for pollination services among plant species can in some cases lead to specialization of the pollinator population to a single plant species (oligolecty). However, collecting pollen from multiple plants - at least at the population level - is evolutionarily stable under a wider parameter range. Finally, we show that, in the presence of pollinators, plants that optimize their investment in attracting vs. rewarding visiting pollinators outcompete plants that do not. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Matsumoto, T K; Kuehnle, A R; Webb, D T
Three major obstacles must be overcome in the anatomical study of Anthurium floral structure and embryo development including presence of mucilage, hardened carpel walls, and hardened seed coat in the developing fruit and seed. Fixation in 6% glutaraldehyde and 1% cetylpyridinium chloride in 0.05 M sodium cacodylate, pH 6.8, effectively fixed or removed mucilage from the locules of Anthurium andraeanum Hort. in spadices. This treatment enhanced infiltration of the embedding medium through the hardened carpel wall into the locule space and decreased the quantity and size of holes in the embedding block during sectioning. Specimens 16 weeks after pollination could be fixed, infiltrated, and observed without physical removal of the seed coat. Embryos may be excised from the seed at later stages without compromising embryo structure.
Wetzstein, Hazel Y; Porter, Justin A; Janick, Jules; Ferreira, Jorge F S
• Artemisia annua produces phytochemicals possessing antimalarial, antitumor, anti-inflammatory, and anthelmintic activities. The main active ingredient, artemisinin, is extremely effective against malaria. Breeding to develop cultivars producing high levels of artemisinin can help meet worldwide demand for artemisinin and its derivatives. However, fundamental reproductive processes, such as the sequence of flowering and fertility, are not well understood and impair breeding and seed propagation programs.• Capitulum structure and floral sequence were studied using light and scanning electron microscopy to describe inflorescence architecture, floret opening, and seed set.• Florets are minute and born in capitula containing pistillate ray florets and hermaphroditic disk florets. Ray florets have elongated stigmatic arms that extend prior to disk floret opening. Disk florets exhibit protandry. During the staminate phase, pollen is released within a staminate tube and actively presented with projections at the tip of stigmas as the pistil elongates. During the pistillate phase, stigmatic arms bifurcate and reflex. Stigmas are of the dry type and stain positively for polysaccharides, lipids, and an intact cuticle. Floret numbers vary with genotype, and capitula are predominantly composed of disk florets. Both ray and disk florets produce filled seed.• Gynomonoecy, early opening of ray florets, and dichogamy of disk florets promote outcrossing in A. annua For breeding and seed development, flowering in genotypes can be synchronized under short days according to the floral developmental stages defined. Floret number and percentage seed fill vary with genotype and may be a beneficial selection criterion. © 2014 Botanical Society of America, Inc.
Ogi, Kazuhiro; Nakashima, Kenji; Chihara, Kazuyasu; Takeuchi, Kenji; Horiguchi, Tomoko; Fujieda, Shigeharu; Sada, Kiyonao
Tyrosine phosphorylation of adaptor protein c-Abl-Src homology 3 (SH3) domain-binding protein-2 (3BP2, also referred to SH3BP2) positively regulates the B-cell antigen receptor (BCR)-mediated signal transduction, leading to the activation of nuclear factor of activated T cells (NFAT). Here we showed the effect of the proline to arginine substitution of 3BP2 in which is the most common mutation in patients with cherubism (P418R) on B-cell receptor signaling. Comparing to the wild type, overexpression of the mutant form of 3BP2 (3BP2-P416R, corresponding to P418R in human protein) enhanced BCR-mediated activation of NFAT. 3BP2-P416R increased the signaling complex formation with Syk, phospholipase C-γ2 (PLC-γ2), and Vav1. In contrast, 3BP2-P416R could not change the association with the negative regulator 14-3-3. Loss of the association mutant that was incapable to associate with 14-3-3 could not mimic BCR-mediated NFAT activation in Syk-deficient cells. Moreover, BCR-mediated phosphorylation of extracellular signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was not affected by P416R mutation. These results showed that P416R mutation of 3BP2 causes the gain of function in B cells by increasing the interaction with specific signaling molecules. © 2011 The Authors. Journal compilation © 2011 by the Molecular Biology Society of Japan/Blackwell Publishing Ltd.
Werkmeister, Elisabeth; Saliou, Jean-Michel; Huot, Ludovic; Sindikubwabo, Fabien; Hakimi, Mohamed Ali; Langsley, Gordon
Toxoplasma gondii possesses a highly polarized secretory system, which efficiently assembles de novo micronemes and rhoptries during parasite replication. These apical secretory organelles release their contents into host cells promoting parasite invasion and survival. Using a CreLox-based inducible knock-out strategy and the ddFKBP over-expression system, we unraveled novel functions of the clathrin adaptor complex TgAP1. First, our data indicate that AP1 in T. gondii likely functions as a conserved heterotetrameric complex composed of the four subunits γ, β, μ1, σ1 and interacts with known regulators of clathrin-mediated vesicular budding such as the unique ENTH-domain containing protein, which we named Epsin-like protein (TgEpsL). Disruption of the μ1 subunit resulted in the mis-sorting of microneme proteins at the level of the Trans-Golgi-Network (TGN). Furthermore, we demonstrated that TgAP1 regulates rhoptry biogenesis by activating rhoptry protein exit from the TGN, but also participates in the post-Golgi maturation process of preROP compartments into apically anchored club-shaped mature organelles. For this latter activity, our data indicate a specific functional relationship between TgAP1 and the Rab5A-positive endosome-like compartment. In addition, we unraveled an original role for TgAP1 in the regulation of parasite division. APμ1-depleted parasites undergo normal daughter cell budding and basal complex assembly but fail to segregate at the end of cytokinesis. PMID:28430827
Raman, Dayanidhi; Sai, Jiqing; Hawkins, Oriana; Richmond, Ann
The chemokine receptor CXCR2 is vital for inflammation, wound healing, angiogenesis, cancer progression and metastasis. Adaptor protein 2 (AP2), a clathrin binding heterotetrameric protein comprised of α, β2, μ2 and σ2 subunits, facilitates clathrin-mediated endocytosis. Mutation of the LLKIL motif in the CXCR2 carboxyl-terminal domain (CTD) results in loss of AP2 binding to the receptor and loss of ligand-mediated receptor internalization and chemotaxis. AP2 knockdown also results in diminished ligand-mediated CXCR2 internalization, polarization and chemotaxis. Using knockdown/rescue approaches with AP2-μ2 mutants, the binding domains were characterized in reference to CXCR2 internalization and chemotaxis. When in an open conformation, μ2 Patch 1 and Patch 2 domains bind tightly to membrane PIP2 phospholipids. When AP2-μ2, is replaced with μ2 mutated in Patch 1 and/or Patch 2 domains, ligand-mediated receptor binding and internalization are not lost. However, chemotaxis requires AP2-μ2 Patch 1, but not Patch 2. AP2-σ2 has been demonstrated to bind dileucine motifs to facilitate internalization. Expression of AP2-σ2 V88D and V98S dominant negative mutants resulted in loss of CXCR2 mediated chemotaxis. Thus, AP2 binding to both membrane phosphatidylinositol phospholipids and dileucine motifs is crucial for directional migration or chemotaxis. Moreover, AP2-mediated receptor internalization can be dissociated from AP2-mediated chemotaxis. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Turner, M. A.
Because of a lack of centralized planning and no widely-adopted standards among hydrological modeling research groups, research communities, and the data management teams meant to support research, there is chaos when it comes to data formats, spatio-temporal resolutions, ontologies, and data availability. All this makes true scientific reproducibility and collaborative integrated modeling impossible without some glue to piece it all together. Our Virtual Watershed Integrated Modeling System provides the tools and modeling framework hydrologists need to accelerate and fortify new scientific investigations by tracking provenance and providing adaptors for integrated, collaborative hydrologic modeling and data management. Under global warming trends where water resources are under increasing stress, reproducible hydrological modeling will be increasingly important to improve transparency and understanding of the scientific facts revealed through modeling. The Virtual Watershed Data Engine is capable of ingesting a wide variety of heterogeneous model inputs, outputs, model configurations, and metadata. We will demonstrate one example, starting from real-time raw weather station data packaged with station metadata. Our integrated modeling system will then create gridded input data via geostatistical methods along with error and uncertainty estimates. These gridded data are then used as input to hydrological models, all of which are available as web services wherever feasible. Models may be integrated in a data-centric way where the outputs too are tracked and used as inputs to "downstream" models. This work is part of an ongoing collaborative Tri-state (New Mexico, Nevada, Idaho) NSF EPSCoR Project, WC-WAVE, comprised of researchers from multiple universities in each of the three states. The tools produced and presented here have been developed collaboratively alongside watershed scientists to address specific modeling problems with an eye on the bigger picture of
Naug, Dhruba; Arathi, H S
Mechanistic models of animal signals posit the occurrence of biases on the part of receivers that could be potentially exploited by signallers. Such biases are most obvious when animals are confronted with exaggerated versions of signals they normally encounter. Signalling systems operating in plant-pollinator interactions are among the most highly coevolved, with plants using a variety of floral signals to attract pollinators. A number of observations suggest that pollinators preferentially visit larger floral displays although the benefit of this to either the plant or the pollinator is not always clear. We use a standard dual-choice experimental protocol to show that honeybees display a receiver bias for exaggerated size and colour contrast--two important components of floral signals--even when such signals do not indicate quality. We discuss the implications of this receiver bias for the evolution of floral displays and its possible exploitation by invading alien plants.
Wu, Zhaobin; Chen, Lanzhen; Wu, Liming; Xue, Xiaofeng; Zhao, Jing; Li, Yi; Ye, Zhihua; Lin, Guanghui
The objective of this study is to test the feasibility of multi-isotopic and elemental analyses combined with chemometric techniques for differentiating the botanical origins of major honey products in China. The stable isotope and elemental compositions of 57 honey samples from four major floral origins in China (i.e., rape honey, acacia honey, vitex honey, and jujube honey) were analyzed using stable isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The results showed that hydrogen and oxygen isotopes could be more suitable than the carbon isotope for discriminating the floral origins of major honeys in China. There were significant differences in the contents of most elements between or among different floral origins. The combination of IRMS and ICP-MS methods provides the most effective and accurate approach (in most cases close to 100% accuracy) for classifying Chinese honeys according to their floral origins.
Pellegrino, Giuseppe; Bellusci, Francesca; Palermo, Anna Maria
... . We estimated male and female reproductive success of three treatment groups, disassembly of floral tube, cutting of lip, and painting of the callus surface, in terms of pollinaria removed/deposited and fruit production...
Hodgins, Kathryn A; Barrett, Spencer C. H
...., Vancouver, British Columbia V6T 1Z4 Canada Narcissus triandrus is a tristylous daffodil from the Iberian Peninsula that has striking geographical variation in floral morphology and style-morph ratios...
Galimba, Kelsey D; Di Stilio, Verónica S
Gene duplications result in paralogs that may be maintained due to the gain of novel functions (neo-functionalization) or the partitioning of ancestral function (sub-functionalization). Plant genomes are especially prone to duplication; paralogs are particularly widespread in the floral MADS box transcription factors that control organ identity through the ABC model of flower development. C class genes establish stamen and carpel identity and control floral meristem determinacy, and are largely conserved across the angiosperm phylogeny. Originally, an additional D class had been identified as controlling ovule identity; yet subsequent studies indicated that both C and D lineage genes more commonly control ovule development redundantly. The ranunculid Thalictrum thalictroides has two orthologs of the Arabidopsis thaliana C class gene AGAMOUS (AG), ThtAG1 and ThtAG2 (Thalictrum thalictroides AGAMOUS1/2). We previously showed that ThtAG1 exhibits typical C class function; here we examine the role of its paralog, ThtAG2. Our phylogenetic analysis shows that ThtAG2 falls within the C lineage, together with ThtAG1, and is consistent with previous findings of a Ranunculales-specific duplication in this clade. However, ThtAG2 is not expressed in stamens, but rather solely in carpels and ovules. This female-specific expression pattern is consistent with D lineage genes, and with other C lineage genes known to be involved in ovule identity. Given the divergent expression of ThtAG2, we tested the hypothesis that it has acquired ovule identity function. Molecular evolution analyses showed evidence of positive selection on ThtAG2-a pattern that supports divergence of function by sub-functionalization. Down-regulation of ThtAG2 by virus-induced gene silencing resulted in homeotic conversions of ovules into carpel-like structures. Taken together, our results suggest that, although ThtAG2 falls within the C lineage, it has diverged to acquire "D function" as an ovule identity gene
Miller, Jill S; Venable, D Lawrence
Plants of Lycium californicum, L. exsertum, and L. fremontii produce flowers that are either male-sterile (female) or hermaphroditic, and populations are morphologically gynodioecious. As is commonly found in gynodioecious species, flowers on female plants are smaller than those on hermaphrodites for a number of floral traits. Floral size dimorphism has often been hypothesized to be the result of either a reduction in female flower size that allows reallocation to greater fruit and seed production, or an increase in hermaphroditic flower size due to the increased importance of pollinator attraction and pollen export for hermaphroditic flowers. We provide a test of these two alternatives by measuring 11 floral characters in eight species of Lycium and using a phylogeny to reconstruct the floral size shifts associated with the evolution of gender dimorphism. Our analyses suggest that female flowers are reduced in size relative to the ancestral condition, whereas flowers on hermaphrodites have changed only slightly in size. Female and hermaphroditic flowers have also diverged both from one another and from ancestral cosexual species in several shape characteristics. We expected sexual dimorphism to be similar among the three dimorphic taxa, as gender dimorphism evolved only a single time in the ancestor of the American dimorphic lineage. While the floral sexual dimorphism is broadly similar among the three dimorphic species, there are some species-specific differences. For example, L. exsertum has the greatest floral size dimorphism, whereas L. fremontii had the greatest size-independent dimorphism in pistil characters. To determine the degree to which phylogenetic uncertainty affected reconstruction of ancestral character states, we performed a sensitivity analysis by reconstructing ancestral character states on alternative topologies. We argue that investigations such as this one, that examine floral evolution from an explicitly phylogenetic perspective, provide new
Vasconcelos, Thais N C; Lucas, Eve J; Faria, Jair E Q; Prenner, Gerhard
Comparative floral ontogeny represents a valuable tool to understand angiosperm evolution. Such an approach may elucidate subtle changes in development that discretely modify floral architecture and underlie reproductive lability in groups with superficial homogeneous morphology. This study presents a comparative survey of floral development in Eugenia (Myrtaceae), one of the largest genera of angiosperms, and shows how previously undocumented ontogenetic trends help to explain the evolution of its megadiversity in contrast to its apparent flower uniformity. Using scanning electron microscopy, selected steps of the floral ontogeny of a model species (Eugenia punicifolia) are described and compared with 20 further species representing all ten major clades in the Eugenia phylogenetic tree. Additional floral trait data are contrasted for correlation analysis and character reconstructions performed against the Myrtaceae phylogenetic tree. Eugenia flowers show similar organ arrangement patterns: radially symmetrical, (most commonly) tetramerous flowers with variable numbers of stamens and ovules. Despite a similar general organization, heterochrony is evident from size differences between tissues and structures at similar developmental stages. These differences underlie variable levels of investment in protection, subtle modifications to symmetry, herkogamic effects and independent androecium and gynoecium variation, producing a wide spectrum of floral display and contributing to fluctuations in fitness. During Eugenia's bud development, the hypanthium (as defined here) is completely covered by stamen primordia, unusual in other Myrtaceae. This is the likely plesiomorphic state for Myrteae and may have represented a key evolutionary novelty in the tribe. Floral evolution in Eugenia depends on heterochronic patterns rather than changes in complexity to promote flexibility in floral strategies. The successful early establishment of Myrteae, previously mainly linked to the
Delle-Vedove, Roxane; Schatz, Bertrand; Dufay, Mathilde
Among the various floral traits involved in pollinator attraction and potentially under selection mediated by pollinators, floral scent/fragrance has been less investigated than other components of floral phenotype. Whether or not pollinator-mediated selection impacts floral scents depends on the heritability of scent/fragrance and the occurrence of some variation within species. Although most studies have investigated how scent varies among species, growing amounts of data are available on variation at the intraspecific level. The results of 81 studies investigating intraspecific variation of floral scents in 132 taxa were reviewed. For each study, whether variation was found in either identity, proportion or absolute quantities of volatile organic compounds (VOCs) was recorded, as well as information with the potential to explain variation, such as methodology, plant origin or pollination biology. Variation was found for almost all investigated species, both among individuals (among and sometimes within populations) and within individuals across different temporal scales. Cases in which such variation is a possible result of pollinator-mediated selection were analysed, by discussing separately selection related to variation in pollinator identity/behaviour among populations or across time, deceit pollination and sex-specific selection. Not surprisingly, in many cases, pollinator-mediated selection alone does not explain the observed variation in floral scent. This led us to review current knowledge on less investigated factors, such as selection mediated by natural enemies, genetic drift and gene flow, environmental constraints, phylogenetic inertia, or biochemical constraints that could be invoked to explain scent variation. This review highlights the great potential of analysing floral scent variation and including it in integrated studies of floral phenotypes. We also have identified the current gaps in our understanding of this complex signal and we propose
Jeiter, Julius; Hilger, Hartmut H; Smets, Erik F; Weigend, Maximilian
Flowers of Geraniaceae and Hypseocharitaceae are generally considered as morphologically simple. However, previous studies indicated complex diversity in floral architecture including tendencies towards synorganization. Most of the species have nectar-rewarding flowers which makes the nectaries a key component of floral organization and architecture. Here, the development of the floral nectaries is studied and placed into the context of floral architecture. Seven species from Geraniaceae and one from Hypseocharitaceae were investigated using scanning electron microscopy and light microscopy. Samples were prepared and processed using standard protocols. The development of the nectary glands follows the same trajectory in all species studied. Minor differences occur in the onset of nectarostomata development. The most striking finding is the discovery that a short anthophore develops via intercalary growth at the level of the nectary glands. This anthophore lifts up the entire flower apart from the nectary gland itself and thus plays an important role in floral architecture, especially in the flowers of Pelargonium. Here, the zygomorphic flowers show a particularly extensive receptacular growth, resulting in the formation of a spur-like receptacular cavity ('inner spur'). The nectary gland is hidden at the base of the cavity. Various forms of compartmentalization, culminating in the 'revolver flower' of Geranium maderense, are described. Despite the superficial similarity of the flowers in Geraniaceae and Hypseocharitaceae, there is broad diversity in floral organization and floral architecture. While the receptacular origin of the spur-like cavity in Pelargonium had already been described, anthophore formation via intercalary growth of the receptacle in the other genera had not been previously documented. In the context of the most recent phylogenies of the families, an evolutionary series for the floral architecture is proposed, underscoring the importance of
Harkess, Richard Lee
This study examined floral initiation in Rudbeckia hirta at the biochemical, cellular, and whole plant levels. Histological and histochemical examination of floral initiation revealed that the pattern of initiation followed closely that described in other species. The primary difference was in the length of time over which initiation and differentiation occurred. When subjected to limited inductive photoperiods, R. hirta responded with a delay in flowering if the plants were re...
Zhao, Y. H.; Z.X. Ren; Lázaro, Amparo; Wang, H.; Bernhardt, P; H. D. Li; Li, D. Z.
Background How floral traits and community composition influence plant specialization is poorly understood and the existing evidence is restricted to regions where plant diversity is low. Here, we assessed whether plant specialization varied among four species-rich subalpine/alpine communities on the Yulong Mountain, SW China (elevation from 2725 to 3910?m). We analyzed two factors (floral traits and pollen vector community composition: richness and density) to determine the degree of plant s...
Gong, W-C; Chen, G; Vereecken, N J; Dunn, B L; Ma, Y-P; Sun, W-B
Traditionally, plant-pollinator interactions have been interpreted as pollination syndrome. However, the validity of pollination syndrome has been widely doubted in modern studies of pollination ecology. The pollination ecology of five Asian Buddleja species, B. asiatica, B. crispa, B. forrestii, B. macrostachya and B. myriantha, in the Sino-Himalayan region in Asia, flowering in different local seasons, with scented inflorescences were investigated during 2011 and 2012. These five species exhibited diverse floral traits, with narrow and long corolla tubes and concealed nectar. According to their floral morphology, larger bees and Lepidoptera were expected to be the major pollinators. However, field observations showed that only larger bees (honeybee/bumblebee) were the primary pollinators, ranging from 77.95% to 97.90% of total visits. In this study, floral scents of each species were also analysed using coupled gas chromatography and mass spectrometry (GC-MS). Although the five Buddleja species emitted differentiated floral scent compositions, our results showed that floral scents of the five species are dominated by substances that can serve as attractive signals to bees, including species-specific scent compounds and principal compounds with larger relative amounts. This suggests that floral scent compositions are closely associated with the principal pollinator assemblages in these five species. Therefore, we conclude that floral scent compositions rather than floral morphology traits should be used to interpret plant-pollinator interactions in these Asian Buddleja species. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.
Saunders, Richard M K
The recent publication of hypotheses explaining the homeotic control of floral organ identity together with the availability of increasingly comprehensive and well-resolved molecular phylogenies presents an ideal opportunity for reassessing current knowledge of floral diversity and evolution in the Annonaceae. This review summarizes currently available information on selected aspects of floral structure and function, including: changes in the number of perianth whorls and the number of perianth parts per whorl; the evolution of sympetaly; the diversity and evolution of pollination chambers (with a novel classification of seven main structural forms of floral chamber based on the different arrangement, size and shape of petals); the evolution of perianth glands; floral unisexuality and hypotheses explaining the unexpectedly high frequency of occurrence of androdioecy; the origin and possible function of inner and outer staminodes; the evolution of stamen connective diversity and theca septation; and the origin of 'true' syncarpy and functionally equivalent extragynoecial compita. In each case, current ideas on the origin, evolution and function are discussed. The information presented in this review enables two main conclusions to be drawn. The first is that changes in the homeotic control of floral organ identity may have had a profound impact on floral structure in several disparate lineages in the family. This is most obvious in Fenerivia, in which a centrifugal shift of floral organ identity has occurred, and in Dasymaschalon, in which a reverse (centripetal) shift has occurred. Other genera that have gained or lost entire perianth whorls are likely to have undergone similar homeotic changes. Attention is also drawn to the extensive functional convergence in Annonaceae flowers, with widespread homoplasy in many characters that have previously been emphasized in higher-level classifications.
Wuest, Samuel E; O'Maoileidigh, Diarmuid S; Rae, Liina; Kwasniewska, Kamila; Raganelli, Andrea; Hanczaryk, Katarzyna; Lohan, Amanda J; Loftus, Brendan; Graciet, Emmanuelle; Wellmer, Frank
How different organs are formed from small sets of undifferentiated precursor cells is a key question in developmental biology. To understand the molecular mechanisms underlying organ specification in plants, we studied the function of the homeotic selector genes APETALA3 (AP3) and PISTILLATA (PI), which control the formation of petals and stamens during Arabidopsis flower development. To this end, we characterized the activities of the transcription factors that AP3 and PI encode throughout flower development by using perturbation assays as well as transcript profiling and genomewide localization studies, in combination with a floral induction system that allows a stage-specific analysis of flower development by genomic technologies. We discovered considerable spatial and temporal differences in the requirement for AP3/PI activity during flower formation and show that they control different sets of genes at distinct phases of flower development. The genomewide identification of target genes revealed that AP3/PI act as bifunctional transcription factors: they activate genes involved in the control of numerous developmental processes required for organogenesis and repress key regulators of carpel formation. Our results imply considerable changes in the composition and topology of the gene network controlled by AP3/PI during the course of flower development. We discuss our results in light of a model for the mechanism underlying sex-determination in seed plants, in which AP3/PI orthologues might act as a switch between the activation of male and the repression of female development.
Zhang, J; Sun, X L; Zhang, L G; Hui, M X; Zhang, M K
Radish floral bud abortion (FBA) is an adverse biological phenomenon that occurs during reproduction. Although FBA occurs frequently, its mechanism remains unknown. To elucidate the molecular mechanism underlying FBA, we detected gene expression differences between aborted and normal buds of radish using cDNA-amplified fragment length polymorphism (AFLP) and real-time polymerase chain reaction (real-time PCR). A total of 221 differentially expressed transcript-derived fragments (TDFs) were detected by 256 cDNA-AFLP primer combinations, of which 114 were upregulated and 107 were downregulated in the aborted buds. A total of 54 TDFs were cloned and sequenced. A BLAST search revealed that all TDFs have homologous sequences and 29 of these corresponded to known genes, whose functions were mainly related to metabolism, stimulus response, transcriptional regulation, and transportation. Expressions of 6 TDFs with different functions were further analyzed by real-time PCR yielding expression profiling results consistent with the cDNA-AFLP analysis. Our results indicated that radish FBA is related to abnormalities in various physiological and biochemical plant processes.
Kostyun, Jamie L; Moyle, Leonie C
Divergence in phenotypic traits often contributes to premating isolation between lineages, but could also promote isolation at postmating stages. Phenotypic differences could directly result in mechanical isolation or hybrids with maladapted traits; alternatively, when alleles controlling these trait differences pleiotropically affect other components of development, differentiation could indirectly produce genetic incompatibilities in hybrids. Here, we determined the strength of nine postmating and intrinsic postzygotic reproductive barriers among 10 species of Jaltomata (Solanaceae), including species with highly divergent floral traits. To evaluate the relative importance of floral trait diversification for the strength of these postmating barriers, we assessed their relationship to floral divergence, genetic distance, geographical context, and ecological differences, using conventional tests and a new linear-mixed modeling approach. Despite close evolutionary relationships, all species pairs showed moderate to strong isolation. Nonetheless, floral trait divergence was not a consistent predictor of the strength of isolation; instead this was best explained by genetic distance, although we found evidence for mechanical isolation in one species, and a positive relationship between floral trait divergence and fruit set isolation across species pairs. Overall, our data indicate that intrinsic postzygotic isolation is more strongly associated with genome-wide genetic differentiation, rather than floral divergence. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.
Andrew V. Novikoff
Full Text Available Species of the tribe Delphinieae have dorsoventralized flowers; their pentamerous calyx and reduced corolla are dorsally spurred and inner spurs are nectariferous. Based on this common floral scheme, Delphinieae species exhibit a wide diversity of floral structures and morphologies. We present here the first investigation of the floral anatomy in Delphinieae. The organization of the floral vascular system has been studied in species representative of the floral morphological diversity of Delphinieae: Aconitum lasiocarpum, Delphinium elatum, and Consolida regalis. The three species show a similar vascularization of the calyx and of the reproductive organs, but exhibit distinct anatomical features in the corolla where the nectaries are borne. The sepals and the stamens have a trilacunar three-traced and a unilacunar one-traced vascularization, respectively. Three free carpels in D. elatum and A. lasiocarpum are basically supplied by six vascular bundles – three independent dorsal bundles and three fused lateral bundles. In C. regalis the single carpel is supplied by three independent vascular bundles (one dorsal and two ventral. Staminodes are not vascularized. The basic type of petal vascularization is unilacunar one-traced, but in the case of C. regalis the derived bilacunar two-traced type has been observed. This latter state arose as a result of the fusion of the two dorsal petal primordia. The results of this first comparative study of the floral anatomy of Delphinieae are discussed with the recent phylogenetic, morphological, and evo-devo findings concerning the tribe.
Kumpf, Robert P; Shi, Chun-Lin; Larrieu, Antoine; Stø, Ida Myhrer; Butenko, Melinka A; Péret, Benjamin; Riiser, Even Sannes; Bennett, Malcolm J; Aalen, Reidunn B
Throughout their life cycle, plants produce new organs, such as leaves, flowers, and lateral roots. Organs that have served their purpose may be shed after breakdown of primary cell walls between adjacent cell files at the site of detachment. In Arabidopsis, floral organs abscise after pollination, and this cell separation event is controlled by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which signals through the leucine-rich repeat receptor-like kinases HAESA (HAE) and HAESA-LIKE2 (HSL2). Emergence of new lateral root primordia, initiated deep inside the root under the influence of auxin, is similarly dependent on cell wall dissolution between cells in the overlaying endodermal, cortical, and epidermal tissues. Here we show that this process requires IDA, HAE, and HSL2. Mutation in these genes constrains the passage of the growing lateral root primordia through the overlaying layers, resulting in altered shapes of the lateral root primordia and of the overlaying cells. The HAE and HSL2 receptors are redundant in function during floral organ abscission, but during lateral root emergence they are differentially involved in regulating cell wall remodeling genes. In the root, IDA is strongly auxin-inducible and dependent on key regulators of lateral root emergence--the auxin influx carrier LIKE AUX1-3 and AUXIN RESPONSE FACTOR7. The expression levels of the receptor genes are only transiently induced by auxin, suggesting they are limiting factors for cell separation. We conclude that elements of the same cell separation signaling module have been adapted to function in different developmental programs.
Su, J; Batzer, A; Sap, J
Receptor tyrosine phosphatases (R-PTPases) have generated interest because of their suspected involvement in cellular signal transduction. The adaptor protein Grb2 has been implicated in coupling receptor tyrosine kinases to Ras. We report that a ubiquitous R-PTPase, R-PTP-alpha, is tyrosine......-phosphorylated and associated in vivo with the Grb2 protein. This association can be reproduced in stably and transiently transfected cells, as well as in vitro using recombinant Grb2 protein. Association requires the presence of an intact SH2 domain in Grb2, as well as tyrosine phosphorylation of R-PTP-alpha. This observation...
Jensen, C.S.; Salchert, K.; Nielsen, K.K.
. To investigate the regulation of meristem identity and the control of floral transition in perennial ryegrass (Lolium perenne) we isolated a ryegrass TERMINAL FLOWER1-like gene, LpTFL1, and characterized it for its function in ryegrass flower development. Perennial ryegrass requires a cold treatment of at least...... 12 weeks to induce flowering. During this period a decrease in LpTFL1 message was detected in the ryegrass apex. However, upon subsequent induction with elevated temperatures and long-day photoperiods, LpTFL1 message levels increased and reached a maximum M:hen the ryegrass apex has formed visible...... and a controller of axillary meristem identity in ryegrass....
Full Text Available Abstract Background Deletion of some Toll-like receptors (TLRs affords protection against cerebral ischemia, but disruption of their known major downstream adaptors does not. To determine whether compensation in the production of downstream effectors by one pathway when the other is disrupted can explain these findings, we examined cytokine/chemokine expression and inflammatory infiltrates in wild-type (WT, MyD88−/− and TRIF-mutant mice following permanent middle cerebral artery occlusion (pMCAO. Methods Cytokine/chemokine expression was measured with a 25-plex bead array in the serum and brains of all three groups of mice at baseline (no surgery/naïve and at 3 hours and 24 hours following pMCAO. Brain inflammatory and neutrophil infiltrates were examined 24 hours following pMCAO. Results IL-6, keratinocyte chemoattractant (KC, granulocyte colony-stimulating factor (G-CSF and IL-10 were significantly decreased in MyD88−/− mice compared to WT mice following pMCAO. Significantly, decreased levels of the neutrophil chemoattractants KC and G-CSF corresponded with a trend toward fewer neutrophils in the brains of MyD88−/− mice. IP-10 was significantly decreased when either pathway was disrupted. MIP-1α was significantly decreased in TRIF-mutant mice, consistent with TRIF-dependent production. MyD88−/− mice showed elevations of a number of Th2 cytokines, such as IL-13, at baseline, which became significantly decreased following pMCAO. Conclusions Both MyD88 and TRIF mediate pathway-specific cytokine production following focal cerebral ischemia. Our results also suggest a compensatory Th2-type skew at baseline in MyD88−/− mice and a paradoxical switch to a Th1 phenotype following focal cerebral ischemia. The MyD88 pathway directs the expression of neutrophil chemoattractants following cerebral ischemia.
Sugden, Christopher; Ross, Susan; Annesley, Sarah J; Cole, Christian; Bloomfield, Gareth; Ivens, Alasdair; Skelton, Jason; Fisher, Paul R; Barton, Geoffrey; Williams, Jeffrey G
phototaxis defect, implying that the early and late functions of LrrB are affected in different ways. These observations, coupled with its domain structure, suggest that LrrB is an SH2 adaptor protein active in diverse developmental signaling pathways. Copyright © 2011 Elsevier Inc. All rights reserved.
SUAREZ HERNANDEZ; LORENA ALEJANDRA; SUAREZ HERNANDEZ; LORENA ALEJANDRA
La evolución por selección natural es el principal mecanismo gobernando la diversidad floral entre especies y poblaciones naturales de plantas con flor. La heterogeneidad ambiental afecta fenotipos florales, identidad y conducta de polinizadores y fenología floral, configurando escenarios selectivos diferenciales y permitiendo la diferenciación de procesos evolutivos entre poblaciones. Posibles diferencias en procesos evolutivos a pequeña escala espacial han sido escasamente estudiad...
Full Text Available Plants of the Glochidion (Phyllanthaceae genus are pollinated exclusively by host-specific Epicephala (Gracillariidae moths. Floral scent has been thought to play key role in the obligate pollination mutualism between Glochidion plants and Epicephala moths, but few studies have been reported about chemical variation in floral volatiles of Glochidion species in China. Floral volatiles of male and female flowers of five Glochidion species in south China were collected by dynamic headspace absorption technique and then were chemically analyzed by using gas chromatography-mass spectrometry. A total of 69 compounds were identified from floral scents of five investigated species. Glochidion hirsutum and G. zeylanicum showed no qualitative differences in floral scent, whereas there were clear variations of floral scent among other species (G. eriocarpum, G. daltonii, and G. sphaerogynum and also they distinctly differed from these two species. Male flowers emitted significantly more scent than female flowers. Glochidion plants exhibited qualitative and quantitative differences in floral scent between two sexes of flowers. The findings suggest that the volatile variation of floral scent among Glochidion species reflects adaptations to specific pollinators. Sexual dimorphism in floral scent has evolved to signal alternative rewards provided by each sex to Epicephala moths.
Full Text Available The mechanism of floral transition in bamboo remains unclear. Dendrocalamus latiflorus (Bambusease, Bambusoideae, Poaceae is an economically and ecologically important clumping bamboo in tropical and subtropical areas. We evaluated morphological characteristics and gene expression profiling to study floral induction and early flower development in D. latiflorus. The detailed morphological studies on vegetative buds and floral organography were completed using paraffin sectioning and scanning electron microscopy. The 3 mm floral buds commence the development of stamen primordia and pistil primordium. Furthermore, homologs of floral transition-related genes, including AP1, TFL1, RFL, PpMADS1, PpMADS2, SPL9, FT, ID1, FCA, and EMF2, were detected and quantified by reverse transcriptase PCR and real-time PCR in vegetative and floral buds, respectively. Distinct expression profiles of ten putative floral initiation homologues that corresponded to the developmental stages defined by bud length were obtained and genes were characterized. Six of the genes (including DlTFL1, DlRFL, DlMADS2, DlID1, DlFCA, DlEMF2 showed statistically significant changes in expression during floral transition. DlAP1 demonstrated a sustained downward trend and could serve as a good molecular marker during floral transition in D. latiflorus. The combined analysis provided key candidate markers to track the transition from the vegetative to reproductive phase.
Wang, Xiaoyan; Zhang, Xuemei; Zhao, Lei; Guo, Zhenhua
The mechanism of floral transition in bamboo remains unclear. Dendrocalamus latiflorus (Bambusease, Bambusoideae, Poaceae) is an economically and ecologically important clumping bamboo in tropical and subtropical areas. We evaluated morphological characteristics and gene expression profiling to study floral induction and early flower development in D. latiflorus. The detailed morphological studies on vegetative buds and floral organography were completed using paraffin sectioning and scanning electron microscopy. The 3 mm floral buds commence the development of stamen primordia and pistil primordium. Furthermore, homologs of floral transition-related genes, including AP1, TFL1, RFL, PpMADS1, PpMADS2, SPL9, FT, ID1, FCA, and EMF2, were detected and quantified by reverse transcriptase PCR and real-time PCR in vegetative and floral buds, respectively. Distinct expression profiles of ten putative floral initiation homologues that corresponded to the developmental stages defined by bud length were obtained and genes were characterized. Six of the genes (including DlTFL1, DlRFL, DlMADS2, DlID1, DlFCA, DlEMF2) showed statistically significant changes in expression during floral transition. DlAP1 demonstrated a sustained downward trend and could serve as a good molecular marker during floral transition in D. latiflorus. The combined analysis provided key candidate markers to track the transition from the vegetative to reproductive phase.
Paul D. Rymer; Steven D. Johnson; Vincent Savolainen
.... Mating patterns and phenotypic selection on floral traits were characterized over two flowering seasons for sympatric corolla tube length morphs of the hawkmothpollinated iris Gladiolus longicollis...
Full Text Available Abstract Background Apple fruit develop over a period of 150 days from anthesis to fully ripe. An array representing approximately 13000 genes (15726 oligonucleotides of 45–55 bases designed from apple ESTs has been used to study gene expression over eight time points during fruit development. This analysis of gene expression lays the groundwork for a molecular understanding of fruit growth and development in apple. Results Using ANOVA analysis of the microarray data, 1955 genes showed significant changes in expression over this time course. Expression of genes is coordinated with four major patterns of expression observed: high in floral buds; high during cell division; high when starch levels and cell expansion rates peak; and high during ripening. Functional analysis associated cell cycle genes with early fruit development and three core cell cycle genes are significantly up-regulated in the early stages of fruit development. Starch metabolic genes were associated with changes in starch levels during fruit development. Comparison with microarrays of ethylene-treated apple fruit identified a group of ethylene induced genes also induced in normal fruit ripening. Comparison with fruit development microarrays in tomato has been used to identify 16 genes for which expression patterns are similar in apple and tomato and these genes may play fundamental roles in fruit development. The early phase of cell division and tissue specification that occurs in the first 35 days after pollination has been associated with up-regulation of a cluster of genes that includes core cell cycle genes. Conclusion Gene expression in apple fruit is coordinated with specific developmental stages. The array results are reproducible and comparisons with experiments in other species has been used to identify genes that may play a fundamental role in fruit development.
Full Text Available Venus kinase receptors (VKRs are invertebrate receptor tyrosine kinases (RTKs formed by an extracellular Venus Fly Trap (VFT ligand binding domain associated via a transmembrane domain with an intracellular tyrosine kinase (TK domain. Schistosoma mansoni VKRs, SmVKR1 and SmVKR2, are both implicated in reproductive activities of the parasite. In this work, we show that the SH2 domain-containing protein SmShb is a partner of the phosphorylated form of SmVKR1. Expression of these proteins in Xenopus oocytes allowed us to demonstrate that the SH2 domain of SmShb interacts with the phosphotyrosine residue (pY979 located in the juxtamembrane region of SmVKR1. This interaction leads to phosphorylation of SmShb on tyrosines and promotes SmVKR1 signaling towards the JNK pathway. SmShb transcripts are expressed in all parasite stages and they were found in ovary and testes of adult worms, suggesting a possible colocalization of SmShb and SmVKR1 proteins. Silencing of SmShb in adult S. mansoni resulted in an accumulation of mature sperm in testes, indicating a possible role of SmShb in gametogenesis.
Andersen, D.C.; Nelson, S. M.
Climate change projections for semiarid and arid North America include reductions in stream discharge that could adversely affect riparian plant species dependent on stream-derived ground water. In order to better understand this potential impact, we used a space-for-time substitution to test the hypotheses that increasing depth-to-groundwater (DGW) is inversely related to Tamarix sp. (saltcedar) flower abundance (F) and nectar production per flower (N). We also assessed whether DGW affected the richness or abundance of insects visiting flowers. We examined Tamarix floral attributes and insect visitation patterns during 2010 and 2011 at three locations along a deep DWG gradient (3.2–4.1 m) on a floodplain terrace adjacent to Las Vegas Wash, an effluent-dominated Mojave Desert stream. Flower abundance and insect visitation patterns differed between years, but no effect from DGW on either F or N was detected. An eruption of a novel non-native herbivore, the splendid tamarisk weevil (Coniatus splendidulus), likely reduced flower production in 2011.
Fishman, Michael A; Hadany, Lilach
Successful cross-fertilization in plant species that rely on animal pollinators depends not just on the number of pollinator visits, but also on these visits' duration. Furthermore, in non-deceptive pollination, a visit's duration depends on the magnitude of the reward provided to the pollinator. Accordingly, plants that rely on biotic pollination have to partition their investment in cross-fertilization assurance between attracting pollinator visits - advertisement, and rewarding visitors to assure that the visit is of productive duration. Here we analyze these processes by a combination of optimality methods and game theoretical modeling. Our results indicate that the optimality in such allocation of resources depends on the types of reward offered to the pollinators. More precisely, we show that plants that offer both food reward and mating rendezvous to pollinators will evolve to allocate a higher proportion of their cross-fertilization assurance budget to advertisement than plants that offer only food reward. That is, our results indicate that pollinators' mating habits may play a role in floral evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.
Richardson, Leif L; Adler, Lynn S; Leonard, Anne S; Andicoechea, Jonathan; Regan, Karly H; Anthony, Winston E; Manson, Jessamyn S; Irwin, Rebecca E
The synthesis of secondary metabolites is a hallmark of plant defence against herbivores. These compounds may be detrimental to consumers, but can also protect herbivores against parasites. Floral nectar commonly contains secondary metabolites, but little is known about the impacts of nectar chemistry on pollinators, including bees. We hypothesized that nectar secondary metabolites could reduce bee parasite infection. We inoculated individual bumblebees with Crithidia bombi, an intestinal parasite, and tested effects of eight naturally occurring nectar chemicals on parasite population growth. Secondary metabolites strongly reduced parasite load, with significant effects of alkaloids, terpenoids and iridoid glycosides ranging from 61 to 81%. Using microcolonies, we also investigated costs and benefits of consuming anabasine, the compound with the strongest effect on parasites, in infected and uninfected bees. Anabasine increased time to egg laying, and Crithidia reduced bee survival. However, anabasine consumption did not mitigate the negative effects of Crithidia, and Crithidia infection did not alter anabasine consumption. Our novel results highlight that although secondary metabolites may not rescue survival in infected bees, they may play a vital role in mediating Crithidia transmission within and between colonies by reducing Crithidia infection intensities. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Richardson, Leif L.; Adler, Lynn S.; Leonard, Anne S.; Andicoechea, Jonathan; Regan, Karly H.; Anthony, Winston E.; Manson, Jessamyn S.; Irwin, Rebecca E.
The synthesis of secondary metabolites is a hallmark of plant defence against herbivores. These compounds may be detrimental to consumers, but can also protect herbivores against parasites. Floral nectar commonly contains secondary metabolites, but little is known about the impacts of nectar chemistry on pollinators, including bees. We hypothesized that nectar secondary metabolites could reduce bee parasite infection. We inoculated individual bumblebees with Crithidia bombi, an intestinal parasite, and tested effects of eight naturally occurring nectar chemicals on parasite population growth. Secondary metabolites strongly reduced parasite load, with significant effects of alkaloids, terpenoids and iridoid glycosides ranging from 61 to 81%. Using microcolonies, we also investigated costs and benefits of consuming anabasine, the compound with the strongest effect on parasites, in infected and uninfected bees. Anabasine increased time to egg laying, and Crithidia reduced bee survival. However, anabasine consumption did not mitigate the negative effects of Crithidia, and Crithidia infection did not alter anabasine consumption. Our novel results highlight that although secondary metabolites may not rescue survival in infected bees, they may play a vital role in mediating Crithidia transmission within and between colonies by reducing Crithidia infection intensities. PMID:25694627
Moyroud, Edwige; Wenzel, Tobias; Middleton, Rox; Rudall, Paula J.; Banks, Hannah; Reed, Alison; Mellers, Greg; Killoran, Patrick; Westwood, M. Murphy; Steiner, Ullrich; Vignolini, Silvia; Glover, Beverley J.
Diverse forms of nanoscale architecture generate structural colour and perform signalling functions within and between species. Structural colour is the result of the interference of light from approximately regular periodic structures; some structural disorder is, however, inevitable in biological organisms. Is this disorder functional and subject to evolutionary selection, or is it simply an unavoidable outcome of biological developmental processes? Here we show that disordered nanostructures enable flowers to produce visual signals that are salient to bees. These disordered nanostructures (identified in most major lineages of angiosperms) have distinct anatomies but convergent optical properties; they all produce angle-dependent scattered light, predominantly at short wavelengths (ultraviolet and blue). We manufactured artificial flowers with nanoscale structures that possessed tailored levels of disorder in order to investigate how foraging bumblebees respond to this optical effect. We conclude that floral nanostructures have evolved, on multiple independent occasions, an effective degree of relative spatial disorder that generates a photonic signature that is highly salient to insect pollinators.
Steiner, Kim E; Kaiser, Roman; Dötterl, Stefan
Evolution involves the interplay between natural selection and phylogenetic constraint. This is particularly evident among the flowering plants where form and diversity of flowers attest to the importance of both pollinator-mediated selection and phylogenetic constraint. Although this has been studied mostly using visible floral characters, invisible volatile chemicals emitted by the flowers should be subject to these same evolutionary forces. Unfortunately, most analyses of floral volatiles have over-emphasized the importance of natural selection and underplayed phylogenetic constraint without quantifying their respective roles in the evolution and composition of floral scents. We used multivariate analyses to test the relative importance of pollinators vs. phylogeny in determining the composition of floral scents among oil-secreting orchids in southern Africa. Floral scents of 42 oil-secreting taxa/ecotypes distributed among 12 subclades in the tribe Diseae were sampled using headspace adsorption and gas chromatography-mass spectroscopy. We identified 257 scent compounds distributed over nine different compound classes, with the majority of scents dominated by aliphatic or benzenoid compounds. The only significant predictor of floral scent among these orchids above the species level was phylogeny. Nevertheless, in two of the clades there were differences in scent profiles at the species and ecotype level that corresponded to different pollinators and were thus suggestive of pollinator-mediated selection. Scent variation was greater than expected and phylogeny was more important than pollinator-mediated selection in predicting the composition of floral scents of oil-secreting orchids, despite the specialized nature of the pollinator reward system.
Ricardo Núñez Miguel
Full Text Available The Toll-like receptor 4 (TLR4 is a class I transmembrane receptor expressed on the surface of immune system cells. TLR4 is activated by exposure to lipopolysaccharides derived from the outer membrane of Gram negative bacteria and forms part of the innate immune response in mammals. Like other class 1 receptors, TLR4 is activated by ligand induced dimerization, and recent studies suggest that this causes concerted conformational changes in the receptor leading to self association of the cytoplasmic Toll/Interleukin 1 receptor (TIR signalling domain. This homodimerization event is proposed to provide a new scaffold that is able to bind downstream signalling adaptor proteins. TLR4 uses two different sets of adaptors; TRAM and TRIF, and Mal and MyD88. These adaptor pairs couple two distinct signalling pathways leading to the activation of interferon response factor 3 (IRF-3 and nuclear factor kappaB (NFkappaB respectively. In this paper we have generated a structural model of the TLR4 TIR dimer and used molecular docking to probe for potential sites of interaction between the receptor homodimer and the adaptor molecules. Remarkably, both the Mal and TRAM adaptors are strongly predicted to bind at two symmetry-related sites at the homodimer interface. This model of TLR4 activation is supported by extensive functional studies involving site directed mutagenesis, inhibition by cell permeable peptides and stable protein phosphorylation of receptor and adaptor TIR domains. Our results also suggest a molecular mechanism for two recent findings, the caspase 1 dependence of Mal signalling and the protective effects conferred by the Mal polymorphism Ser180Leu.
Full Text Available Vpx is a small virion-associated adaptor protein encoded by viruses of the HIV-2/SIVsm lineage of primate lentiviruses that enables these viruses to transduce monocyte-derived cells. This probably reflects the ability of Vpx to overcome an as yet uncharacterized block to an early event in the virus life cycle in these cells, but the underlying mechanism has remained elusive. Using biochemical and proteomic approaches, we have found that Vpx protein of the pathogenic SIVmac 239 strain associates with a ternary protein complex comprising DDB1 and VprBP subunits of Cullin 4-based E3 ubiquitin ligase, and DDA1, which has been implicated in the regulation of E3 catalytic activity, and that Vpx participates in the Cullin 4 E3 complex comprising VprBP. We further demonstrate that the ability of SIVmac as well as HIV-2 Vpx to interact with VprBP and its associated Cullin 4 complex is required for efficient reverse transcription of SIVmac RNA genome in primary macrophages. Strikingly, macrophages in which VprBP levels are depleted by RNA interference resist SIVmac infection. Thus, our observations reveal that Vpx interacts with both catalytic and regulatory components of the ubiquitin proteasome system and demonstrate that these interactions are critical for Vpx ability to enable efficient SIVmac replication in primary macrophages. Furthermore, they identify VprBP/DCAF1 substrate receptor for Cullin 4 E3 ubiquitin ligase and its associated protein complex as immediate downstream effector of Vpx for this function. Together, our findings suggest a model in which Vpx usurps VprBP-associated Cullin 4 ubiquitin ligase to enable efficient reverse transcription and thereby overcome a block to lentivirus replication in monocyte-derived cells, and thus provide novel insights into the underlying molecular mechanism.
Mariela Nuñez Florentin
Full Text Available ABSTRACT The genus Oldenlandia (Rubiaceae has a conflicting generic delimitation, with representatives that show different floral syndromes. Oldenlandia salzmannii is a marshy herb that is widespread in South America. It is heterostylous, specifically distylous, and self-compatible. Recent molecular phylogenetic studies found that this species forms a clade that is isolated from the remaining described taxa of Oldenlandia. Information about the floral anatomy and reproductive biology of genera in the Spermacoceae tribe, particularly Oldenlandia, is insufficient, especially among the neotropical species. Accordingly, the present study aimed at contributing information on the reproductive biology of Oldenlandia salzmannii by analyzing its floral morpho-anatomy, morphometrics and phenology of both floral morphs. These analyses were conducted with natural, cultivated and fixed material using optical and scanning electron microscopes. Morphologically, the species is typically heterostylous with two floral morphs, long-styled and short-styled, the main difference being the indument of the corolla. The short-styled flowers have larger anthers and pollen grains. Morphometrics show a high degree of herkogamic reciprocity. The mature ovules have a hemitropous position, which is the first record of this position for the Spermacoceae tribe. This study represents the first comprehensive morphological study of Oldenlandia salzmannii.
Laufs, Patrick; Coen, Enrico; Kronenberger, Jocelyne; Traas, Jan; Doonan, John
The UNUSUAL FLORAL ORGANS (UFO) gene is required for several aspects of floral development in Arabidopsis including specification of organ identity in the second and third whorls and the proper pattern of primordium initiation in the inner three whorls. UFO is expressed in a dynamic pattern during the early phases of flower development. Here we dissect the role of UFO by ubiquitously expressing it in ufo loss-of-function flowers at different developmental stages and for various durations using an ethanol-inducible expression system. The previously known functions of UFO could be separated and related to its expression at specific stages of development. We show that a 24- to 48-hour period of UFO expression from floral stage 2, before any floral organs are visible, is sufficient to restore normal petal and stamen development. The earliest requirement for UFO is during stage 2, when the endogenous UFO gene is transiently expressed in the centre of the wild-type flower and is required to specify the initiation patterns of petal, stamen and carpel primordia. Petal and stamen identity is determined during stages 2 or 3, when UFO is normally expressed in the presumptive second and third whorl. Although endogenous UFO expression is absent from the stamen whorl from stage 4 onwards, stamen identity can be restored by UFO activation up to stage 6. We also observed floral phenotypes not observed in loss-of-function or constitutive gain-of-function backgrounds, revealing additional roles of UFO in outgrowth of petal primordia.
Anderson, Ingrid A; Busch, Jeremiah W
Natural selection should favor the integration of floral traits that enhance pollen export and import in plant populations that rely upon pollinators. If this is true, then phenotypic correlations between floral traits should weaken in self-fertilizing groups that do not require pollinator visitation to produce seed. We tested this hypothesis in Leavenworthia, a plant genus in which there have been multiple independent losses of the sporophytic self-incompatibility system found throughout the Brassicaceae. In particular, we conducted phylogenetically independent contrasts of floral trait correlations between two pairs of self-incompatible (SI) and self-compatible (SC) sister taxa. In support of the hypothesis that pollinator-mediated selection integrates floral traits, we found that both SC Leavenworthia taxa have weaker overall floral correlations in comparison to sister taxa that rely upon pollinators. The two independently derived SC Leavenworthia flowers have significantly weaker stamen-petal or pistil-petal correlations, respectively, whereas the stamen-pistil correlation remains constant. These patterns suggest that relaxation of pollinator-mediated selection weakens the integration of traits associated with pollen export and import. The retention of high stamen-pistil correlations in the SC taxa of Leavenworthia further implies that the integration of these traits is either constrained or maintained by selection favoring the successful transfer of pollen within flowers to secure self-pollination.
Molet, Mathieu; Chittka, Lars; Raine, Nigel E.
Recruitment in social insects often involves not only inducing nestmates to leave the nest, but also communicating crucial information about finding profitable food sources. Although bumblebees transmit chemosensory information (floral scent), the transmission mechanism is unknown as mouth-to-mouth fluid transfer (as in honeybees) does not occur. Because recruiting bumblebees release a pheromone in the nest that triggers foraging in previously inactive workers, we tested whether this pheromone helps workers learn currently rewarding floral odours, as found in food social learning in rats. We exposed colonies to artificial recruitment pheromone, paired with anise scent. The pheromone did not facilitate learning of floral scent. However, we found that releasing floral scent in the air of the colony was sufficient to trigger learning and that learning performance was improved when the chemosensory cue was provided in the nectar in honeypots; probably because it guarantees a tighter link between scent and reward, and possibly because gustatory cues are involved in addition to olfaction. Scent learning was maximal when anise-scented nectar was brought into the nest by demonstrator foragers, suggesting that previously unidentified cues provided by successful foragers play an important role in nestmates learning new floral odours.
Full Text Available Luculia plants are famed ornamentals with sweetly fragrant flowers. Luculia yunnanensis Hu is an endemic plant from Yunnan Province, China. Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS was used to identify the volatile organic compounds (VOCs of the different flower development stages of L. yunnanensis for the evaluation of floral volatile polymorphism. The results showed that a total of 40 compounds were identified at four different stages. The main aroma-active compounds were 3-carene, α-cubebene, α-copaene, δ-cadinene, and isoledene. Floral scent emission had the tendency to ascend first and descend in succession, reaching its peak level at the initial-flowering stage. The richest diversity of floral volatiles was detected at the full-flowering stage. Principal component analysis (PCA indicated that the composition and its relative content of floral scent differed at the whole flower development stage. In comparison with the other two species of Luculia (L. pinceana and L. gratissima, the composition and its relative content of floral scent were also different among the tree species.
Li, Yuying; Wan, Youming; Sun, Zhenghai; Li, Taiqiang; Liu, Xiongfang; Ma, Hong; Liu, Xiuxian; He, Rui; Ma, Yan; Li, Zhenghong
Luculia plants are famed ornamentals with sweetly fragrant flowers. Luculia yunnanensis Hu is an endemic plant from Yunnan Province, China. Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to identify the volatile organic compounds (VOCs) of the different flower development stages of L. yunnanensis for the evaluation of floral volatile polymorphism. The results showed that a total of 40 compounds were identified at four different stages. The main aroma-active compounds were 3-carene, α-cubebene, α-copaene, δ-cadinene, and isoledene. Floral scent emission had the tendency to ascend first and descend in succession, reaching its peak level at the initial-flowering stage. The richest diversity of floral volatiles was detected at the full-flowering stage. Principal component analysis (PCA) indicated that the composition and its relative content of floral scent differed at the whole flower development stage. In comparison with the other two species of Luculia (L. pinceana and L. gratissima), the composition and its relative content of floral scent were also different among the tree species.
Atay Ayşe Nilgun
Full Text Available The timing of blooming in spring is highly crucial for temperate zone tree fruit production. In this study, we aimed to investigate floral development using the all parents and full-sib offsprings of two different crossing combinations (‘Kaşel 37’ × ‘Delbarestivale’ and ‘Kaşel 41’ × ‘Williams’ Pride’. Assessments of variability in floral development have been done according to a numerical assessment scheme defined by ten stages (stage 0-9. The assessments were conducted three different dates, early (21 04, intermediate (28 04, and late (05 05. The results showed significant variations for floral development among the 273 genotypes. In particular, the genotypes 326, 340, 369, 88 and 146 were found as superiors for floral development. The broad sense heritability (h2 b for floral development was reliable on the first assessment date, with no reliability on the other assessment dates. Our results would be useful to geneticists and breeders. Key words: Amasya, breeding, F1, Malus slyvestris, new cultivar, progeny, spring frost.
Gouvêa, Cantídio Fernando; Dornelas, Marcelo Carnier; Rodriguez, Adriana Pinheiro Martinelli
Background and Aims Floral development of Cedrela and Toona, the genera comprising the basal tribe Cedreleae of the sub-family Swietenioideae of Meliaceae, is described. The focus was on three endangered, ecologically and economically important species: Cedrela fissilis, Cedrela odorata and Toona ciliata. The aims of the study were to characterize the patterns of floral development in the tribe and to establish apomorphic and plesiomorphic floral characters in relation to other taxa within the family based on the current molecular phylogeny of Meliaceae. Methods A detailed floral structural and developmental study was completed using both scanning electron microscopy and visualization of microtome sections with a light microscope. Key Results Twelve floral developmental stages were identified. The initial development of the pentamerous flowers of both Toona and Cedrela is strikingly similar. The morphological differences observed between them are due to differential patterns of organ elongation and adnation/connation occurring late in development. Additionally, the formation of functionally male and female flowers was found to occur at specific positions within the inflorescence. Conclusions Due to the basal position of the tribe Cedreleae in the phylogeny of Meliaceae, functionally either male or female pentamerous flowers and the presence of (at least partially) free stamens may be considered plesiomorphic traits within the family. In contrast, sympetaly and the absence of nectaries in Cedrela species are synapomorphies. PMID:17981877
Full Text Available Identifying the processes that drive community assembly has long been a central theme in ecology. For microorganisms, a traditional prevailing hypothesis states that "everything is everywhere, but the environment selects". Although the bacterial community in floral nectar may be affected by both atmosphere (air-borne bacteria and animals as dispersal vectors, the environmental and geographic factors that shape microbial communities in floral nectar are unknown. We studied culturable bacterial communities in Asphodelus aestivus floral nectar and in its typical herbivorous bug Capsodes infuscatus, along an aridity gradient. Bacteria were sampled from floral nectar and bugs at four sites, spanning a geographical range of 200 km from Mediterranean to semi-arid conditions, under open and bagged flower treatments. In agreement with the niche assembly hypothesis, the differences in bacterial community compositions were explained by differences in abiotic environmental conditions. These results suggest that microbial model systems are useful for addressing macro-ecological questions. In addition, similar bacterial communities were found in the nectar and on the surface of the bugs that were documented visiting the flowers. These similarities imply that floral nectar bacteria dispersal is shaped not only by air borne bacteria and nectar consumers as previously reported, but also by visiting vectors like the mirid bugs.
Yan, Juan; Wang, Gang; Sui, Yi; Wang, Menglin; Zhang, Ling
Floral colour change is visual signals for pollinators to avoid old flowers and increase pollination efficiency. Quisqualis indica flowers change colour from white to pink to red may be associated with a shift from moth to butterfly pollination. To test this hypothesis, we investigated Q. indica populations in Southwest China. Flowers secreted nectar continuously from the evening of anthesis until the following morning, then decreased gradually with floral colour change. The scent compounds in the three floral colour stages were similar; however, the scent composition was different, and the scent emission rate decreased from the white to red stage. Dichogamy in Q. indica prevents self-pollination and interference of male and female functions. Controlled pollinations demonstrated that this species is self-incompatible and needs pollinators for seed production. Different pollinators were attracted in each floral colour stage; mainly moths at night and bees and butterflies during the day. Observations of open-pollinated inflorescences showed that white flowers had a higher fruit set than pink or red flowers, indicating the high contribution of moths to reproductive success. We concluded that the nectar and scent secretion are related to floral colour change in Q. indica, in order to attract different pollinators and promote reproductive fitness.
Buzatto, Cristiano Roberto; Davies, Kevin L; Singer, Rodrigo B; Pires dos Santos, Rinaldo; van den Berg, Cássio
Capanemia Barb. Rodr. comprises seven species that mostly inhabit the Brazilian Atlantic Rain Forest domain. The genus currently consists of two sections: Capanemia Cogn. and Planifolia Pabst, distinguished on the basis of leaf shape. We compare the floral morphology and anatomy of all species to determine whether separation into sections is supported by floral characters. Both fresh flowers and herbarium specimens were investigated, and column and pollinarium features, together with the presence or absence of floral rewards, recorded. Anatomical features were examined using both light microscopy and scanning electron microscopy. With the sole exception of Capanemia therezae, all species shared a distinctive set of floral characters. Flowers were mostly white or yellowish-white and fragrant, and column wings were positioned parallel to the labellum, concealing the stigmatic cavity. Pollinaria had proportionally long tegular stipes and clavate to reniform pollinia, whereas the labellum possessed a conspicuous indument of trichomes, but was devoid of nectar or any other secretion that might function as a food-reward. Capanemia therezae, however, was exceptional in having greenish, unscented flowers with short, rounded and divergent column wings and an exposed stigmatic cavity. Its pollinaria had proportionally short tegular stipes and round pollinia, whereas the labellum lacked trichomes. Droplets of nectar were evident on the adaxial surface of the labellum, adjacent to the callus. Floral features did not support the currently accepted sectional division of Capanemia. If ongoing phylogenetic studies demonstrate that both sections are indeed monophyletic, then these taxa should be distinguished solely on the basis of foliar features.
Flacher, Floriane; Raynaud, Xavier; Hansart, Amandine; Motard, Eric; Dajoz, Isabelle
Plant traits related to attractiveness to pollinators (e.g. flowers and nectar) can be sensitive to abiotic or biotic conditions. Soil nutrient availability, as well as interactions among insect-pollinated plants species, can induce changes in flower and nectar production. However, further investigations are needed to determine the impact of interactions between insect-pollinated species and abiotically pollinated species on such floral traits, especially floral rewards. We carried out a pot experiment in which three insect-pollinated plant species were grown in binary mixtures with four wind-pollinated plant species, differing in their competitive ability. Along the flowering period, we measured floral traits of the insect-pollinated species involved in attractiveness to pollinators (i.e. floral display size, flower size, daily and total 1) flower production, 2) nectar volume, 3) amount of sucrose allocated to nectar). Final plant biomass was measured to quantify competitive interactions. For two out of three insect-pollinated species, we found that the presence of a wind-pollinated species can negatively impact floral traits involved in attractiveness to pollinators. This effect was stronger with wind-pollinated species that induced stronger competitive interactions. These results stress the importance of studying the whole plant community (and not just the insect-pollinated plant community) when working on plant-pollinator interactions.
Newman, Ethan; Manning, John; Anderson, Bruce
Geographic variation in floral morphology is often assumed to reflect geographic variation in pollinator communities and associated divergence in selective pressures. We studied populations of Nerine humilis (Amaryllidaceae) to assess whether geographic variation in floral form is the result of local adaptation to different pollinator communities. We first tested for associations between floral traits and visitor communities, and found that populations with similar floral morphologies were visited by similar insect communities. Mean style length in each population was also closely associated with the mean body length of the local visitor community. A reciprocal translocation experiment demonstrated that native phenotypes set more seed than translocated phenotypes. Single visitation experiments showed that native flowers received more pollen, and set more seed per visit, than introduced phenotypes in both populations. This suggests that the effectiveness of pollinator visits is determined by the degree of mechanical fit between flowers and visitors. We provide strong evidence that the observed among-population variation in floral traits is an adaptive response to geographic variation in the pollinator community. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
Gómez, José M; Perfectti, Francisco; Lorite, Juan
Pollinator-mediated evolutionary divergence has seldom been explored in generalist clades because it is assumed that pollinators in those clades exert weak and conflicting selection. We investigate whether pollinators shape floral diversification in a pollination generalist plant genus, Erysimum. Species from this genus have flowers that appeal to broad assemblages of pollinators. Nevertheless, we recently reported that it is possible to sort plant species into pollination niches varying in the quantitative composition of pollinators. We test here whether floral characters of Erysimum have evolved as a consequence of shifts among pollination niches. For this, we quantified the evolutionary lability of the floral traits and their phylogenetic association with pollination niches. As with pollination niches, Erysimum floral traits show weak phylogenetic signal. Moreover, floral shape and color are phylogenetically associated with pollination niche. In particular, plants belonging to a pollination niche dominated by long-tongued large bees have lilac corollas with parallel petals. Further analyses suggest, however, that changes in color preceded changes in pollination niche. Pollinators seem to have driven the evolution of corolla shape, whereas the association between pollination niche and corolla color has probably arisen by lilac-flowered Erysimum moving toward certain pollination niches for other adaptive reasons. © 2015 The Author(s).
Tripp, Erin A; Manos, Paul S
Pollination systems frequently reflect adaptations to particular groups of pollinators. Such systems are indicative of evolutionary specialization and have been important in angiosperm diversification. We studied the evolution of pollination systems in the large genus Ruellia. Phylogenetic analyses, morphological ordinations, ancestral state reconstructions, and a character mapping simulation were conducted to reveal key patterns in the direction and lability of floral characters associated with pollination. We found significant floral morphological differences among species that were generally associated with different groups of floral visitors. Floral evolution has been highly labile and also directional. Some specialized systems such as hawkmoth or bat pollination are likely evolutionary dead-ends. In contrast, specialized pollination by hummingbirds is clearly not a dead-end. We found evidence for multiple reverse transitions from presumed ancestral hummingbird pollination to more derived bee or insect pollination. These repeated origins of insect pollination from hummingbird-pollinated ancestors have not evolved without historical baggage. Flowers of insect-pollinated species derived from hummingbird-pollinated ancestors are morphologically more similar to hummingbird flowers than they are to other more distantly related insect-pollinated flowers. Finally, some pollinator switches were concomitant with changes in floral morphology that are associated with those pollinators. These observations are consistent with the hypothesis that some transitions have been adaptive in the evolution of Ruellia.
Lorena I. Guevara
Full Text Available Copernicia y Washingtonia son dos de los géneros de Trachycarpeae para los cuales no ha sido propuesta una clasificación subtribal debido a la carencia de resolución en los estudios filogenéticos. La morfología y anatomía floral dentro de Coryphoideae han sido útiles para la delimitación de taxones y apoyo de relaciones. En este trabajo se presenta una descripción de la estructura morfo-anatómica de las flores de C. tectorum y W. filifera, con la finalidad de explorar caracteres reproductivos que puedan aclarar su ubicación dentro de la subfamilia y contribuir con estudios de biología floral. Se fijaron flores de especimenes cultivados de ambos taxones y frutos en desarrollo de C. tectorum, se realizaron disecciones para las descripciones morfológicas y cortes anatómicos seriados para la obtención de láminas permanentes utilizando técnicas convencionales con parafina. Todos los procedimientos fueron llevados a cabo en el Laboratorio de Morfo-Anatomía, Facultad de Agronomía de la Universidad Central de Venezuela (UCV. Ambas especies tienen flores hermafroditas. Las flores de C. tectorum tienen perianto engrosado y pubescente. Las flores de W. filifera presentan un cáliz irregularmente dentado y corola corto-acuminada. Se reportan células con drusas en el tubo estaminal de C. tectorum. Uno solo de los carpelos de C. tectorum se desarrolla en fruto y se encontró una capa de células con rafidios que podrían formar el endocarpo crustáceo en los frutos maduros. W. filifera presenta pocas capas de células de paredes engrosadas y tejido esclerenquimático en el mesofilo del perianto, gineceo con carpelos fusionados en el ápice del ovario (en su porción ventral, libres en la base y en el ápice del estilo, donde presenta suturas ventrales abiertas. Los pétalos de C. tectorum poseen una hipodermis ventral de células con paredes muy engrosadas, gineceo con carpelos fusionados en el ápice del ovario, libres y adpresos en su
Kyauk, C.; Belisle, M.; Fukami, T.
Nectar is such a sugar-rich resource that serves as a natural habitat in which microbes thrive. As a result, yeasts arrive to nectar on the bodies of pollinators such as hummingbirds and bees. Yeasts use the sugar in nectar for their own needs when introduced. This research focuses on the identification of different types of yeast that are found in the nectar of Mimulus aurantiacus (commonly known as sticky monkey-flower). Unopened Mimulus aurantiacus flower buds were tagged at Jasper Ridge and bagged three days later. Floral nectar was then extracted and plated on potato dextrose agar. Colonies on the plates were isolated and DNA was extracted from each sample using QIAGEN DNeasy Plant Mini Kit. The DNA was amplified through PCR and ran through gel electrophoresis. The PCR product was used to clone the nectar samples into an E.coli vector. Finally, a phylogenetic tree was created by BLAST searching sequences in GenBank using the Internal Transcribed Space (ITS) locus. It was found that 18 of the 50 identified species were Candida magnifica, 14 was Candida rancensis, 6 were Crytococcus albidus and there were 3 or less of the following: Starmella bombicola, Candida floricola, Aureobasidium pullulans, Pichia kluyvera, Metschnikowa cibodaserisis, Rhodotorua colostri, and Malassezia globosa. The low diversity of the yeast could have been due to several factors: time of collection, demographics of Jasper Ridge, low variety of pollinators, and sugar concentration of the nectar. The results of this study serve as a necessary first step for a recently started research project on ecological interactions between plants, pollinators, and nectar-living yeast. More generally, this research studies the use of the nectar-living yeast community as a natural microcosm for addressing basic questions about the role of dispersal and competitive and facilitative interactions in ecological succession.
Seedat, Noorina; Dinsdale, Adrian; Ong, Eng Kok; Gendall, Anthony Richard
Flowering time in the model plant Arabidopsis thaliana is regulated by both external environmental signals and internal developmental pathways. Natural variation at the FLOWERING H (FLH) locus has previously been described, with alleles present in the Cape Verde Islands accession causing early flowering, particularly after vernalization. The mechanism of FLH-induced early flowering is not understood. Here, the integration of FLH activity into the known flowering time pathways is described using molecular and genetic approaches. The identification of molecular markers that co-segregated with the FLH locus allowed the generation of multiple combinations of FLH alleles with mutations in flowering time genes in different flowering pathways. Combining an early flowering FLH allele with mutations in vernalization pathway genes that regulate FLC expression revealed that FLH appears to act in parallel to FLC. Surprisingly, the early flowering allele of FLH requires the floral integrator FD, but not FT, to accelerate flowering. This suggests a model in which some alleles of FLH are able to affect the FD-dependent activity of the floral activator complex.
Qualitative changes in floral pollen protein have been shown to be an important aspect of pollinator health. Flowering late in the season, goldenrod (Solidago spp.), provides an essential autumnal source of floral pollen for wild bee and honeybee populations prior to winter, with tall or Canada gol...
Vleugel, Mathijs; Omerzu, Manja; Groenewold, Vincent; Hadders, Michael A; Lens, Susanne M A; Kops, Geert J P L
Regulated recruitment of the kinase-adaptor complex BUB1/BUB3 to kinetochores is crucial for correcting faulty chromosome-spindle attachments and for spindle assembly checkpoint (SAC) signaling. BUB1/BUB3 localizes to kinetochores by binding phosphorylated MELT motifs (MELpT) in the kinetochore
Thiele, Jan; Hansen, Thomas Møller; Siegismund, Hans Redlef
The magnitude and variation of inbreeding depression (ID) within populations is important for the evolution and maintenance of mixed mating systems. We studied ID and its genetic variation in a range of floral and fitness traits in a small and large population of the perennial herb Silene nutans......, using controlled pollinations in a fully factorial North Carolina II design. Floral traits and early fitness traits, that is seed mass and germination rate, were not much affected by inbreeding (delta0.4). Lack of genetic correlations indicated that ID in floral, early and late traits is genetically...... decoupled. There was a trend that the smaller population was less affected by ID than the large one, although the differences were not significant for most traits. Hence, evidence for purging of deleterious alleles remains inconclusive in this study. Genetic variation in ID among paternal families...
DANIEL A.V. MONTERO
Full Text Available ABSTRACT This study describes for the first time the chemical composition and olfactive description of floral scent from Brazilian Passiflora (Passiflora edulis Sim, Passiflora alata Curtis, Passiflora cincinnata Mast., Passiflora coccinea Aubl. and Passiflora quadrangularis L.. Five species were grown in greenhouse at the Agronomic Institute (IAC, São Paulo, Brazil. Volatile compounds were collected using dynamic headspace. Analyses of scent composition were performed by gas chromatograph coupled to mass spectrometer. Identification of chemical constituents was conducted through of retention index followed by comparative analysis of mass spectra with specialized databases. The olfactive descriptions of floral scent from each species was evaluated for a professional perfumer. High interspecific diversity was found between chemical compositions of floral scent within Passiflora and different bouquets were observed amount the studied species. Mayor constituents were linalool (P. alata, geraniol (P. quadrangularis, 1,4-dimethoxybenzene (P. edulis, benzaldehyde (P. cincinnata and 2-methyl-3-pentanone (P. coccinea.
Rosas-Guerrero, Víctor; Aguilar, Ramiro; Martén-Rodríguez, Silvana; Ashworth, Lorena; Lopezaraiza-Mikel, Martha; Bastida, Jesús M; Quesada, Mauricio
The idea of pollination syndromes has been largely discussed but no formal quantitative evaluation has yet been conducted across angiosperms. We present the first systematic review of pollination syndromes that quantitatively tests whether the most effective pollinators for a species can be inferred from suites of floral traits for 417 plant species. Our results support the syndrome concept, indicating that convergent floral evolution is driven by adaptation to the most effective pollinator group. The predictability of pollination syndromes is greater in pollinator-dependent species and in plants from tropical regions. Many plant species also have secondary pollinators that generally correspond to the ancestral pollinators documented in evolutionary studies. We discuss the utility and limitations of pollination syndromes and the role of secondary pollinators to understand floral ecology and evolution. © 2014 John Wiley & Sons Ltd/CNRS.
Hegland, Stein Joar; Totland, Ørjan
Knowledge about plant-plant interactions for pollinator service at the plant community level is still scarce, although such interactions may be important to seed production and hence the population dynamics of individual plant species and the species compositions of communities. An important step towards a better understanding of pollination interactions at the community level is to assess if the variation in floral traits among plant species explain the variation in flower visitation frequency among those species. We investigated the relative importance of various floral traits for the visitation frequency of all insects, and bumblebees and flies separately, to plant species by measuring the visitation frequency to all insect-pollinated species in a community during an entire flowering season. Visitation frequency was identified to be strongly positive related to the visual display area and the date of peak flowering of plant species. Categorical variables, such as flower form and symmetry, were important to the visitation frequency of flies only. We constructed floral similarity measures based on the species' floral traits and found that the floral similarity for all species' traits combined and the continuous traits separately were positively related to individual visitation frequency. On the other hand, plant species with similar categorical floral traits did not have similar visitation frequencies. In conclusion, our results show that continuous traits, such as flower size and/or density, are more important for the variation in visitation frequency among plant species than thought earlier. Furthermore, differences in visitation frequency among pollinator groups give a poor support to the expectations derived from the classical pollination syndromes.
Full Text Available The architectural complexity of flower structures (hereafter referred to as floral complexity may be linked to pollination by specialized pollinators that can increase the probability of successful seed set. As plant-pollinator systems become fragile, a loss of such specialized pollinators could presumably result in an increased likelihood of pollination failure. This is an issue likely to be particularly evident in plants that are currently rare. Using a novel index describing floral complexity we explored whether this aspect of the structure of flowers could be used to predict vulnerability of plant species to extinction. To do this we defined plant vulnerability using the Red Data Book of Rare and Threatened Plants of Greece, a Mediterranean biodiversity hotspot. We also tested whether other intrinsic (e.g. life form, asexual reproduction or extrinsic (e.g. habitat, altitude, range-restrictedness factors could affect plant vulnerability. We found that plants with high floral complexity scores were significantly more likely to be vulnerable to extinction. Among all the floral complexity components only floral symmetry was found to have a significant effect, with radial-flower plants appearing to be less vulnerable. Life form was also a predictor of vulnerability, with woody perennial plants having significantly lower risk of extinction. Among the extrinsic factors, both habitat and maximum range were significantly associated with plant vulnerability (coastal plants and narrow-ranged plants are more likely to face higher risk. Although extrinsic and in particular anthropogenic factors determine plant extinction risk, intrinsic traits can indicate a plant's proneness to vulnerability. This raises the potential threat of declining global pollinator diversity interacting with floral complexity to increase the vulnerability of individual plant species. There is potential scope for using plant-pollinator specializations to identify plant species
Dhandapani, Savitha; Jin, Jingjing; Sridhar, Vishweshwaran; Sarojam, Rajani; Chua, Nam-Hai; Jang, In-Cheol
Magnolia champaca, commonly known as champak is a well-known tree due to its highly fragrant flowers. Champak floral scent is attributed to a complex mix of volatile organic compounds (VOCs). These aromatic flowers are widely used in flavors and fragrances industry. Despite its commercial importance, the VOC biosynthesis pathways in these flowers are largely unknown. Here, we combine metabolite and RNA sequencing (RNA-seq) analyses of fully opened champak flowers to discover the active VOC biosynthesis pathways as well as floral scent-related genes. Volatile collection by headspace method and analysis by gas chromatography-mass spectrometry (GC-MS) identified a total of 43 VOCs from fully opened champak flowers, of which 46.9% were terpenoids, 38.9% were volatile esters and 5.2% belonged to phenylpropanoids/benzenoids. Sequencing and de novo assembly of champak flower transcriptome yielded 47,688 non-redundant unigenes. Transcriptome assembly was validated using standard polymerase chain reaction (PCR) based approach for randomly selected unigenes. The detailed profiles of VOCs led to the discovery of pathways and genes involved in floral scent biosynthesis from RNA-seq data. Analysis of expression levels of many floral-scent biosynthesis-related unigenes in flowers and leaves showed that most of them were expressed higher in flowers than in leaf tissues. Moreover, our metabolite-guided transcriptomics, in vitro and in vivo enzyme assays and transgenic studies identified (R)-linalool synthase that is essential for the production of major VOCs of champak flowers, (R)-linalool and linalool oxides. As our study is the first report on transcriptome analysis of Magnolia champaca, this transcriptome dataset that serves as an important public information for functional genomics will not only facilitate better understanding of ecological functions of champak floral VOCs, but also provide biotechnological targets for sustainable production of champak floral scent.
Simon van Mourik
Full Text Available An intriguing phenomenon in plant development is the timing and positioning of lateral organ initiation, which is a fundamental aspect of plant architecture. Although important progress has been made in elucidating the role of auxin transport in the vegetative shoot to explain the phyllotaxis of leaf formation in a spiral fashion, a model study of the role of auxin transport in whorled organ patterning in the expanding floral meristem is not available yet. We present an initial simulation approach to study the mechanisms that are expected to play an important role. Starting point is a confocal imaging study of Arabidopsis floral meristems at consecutive time points during flower development. These images reveal auxin accumulation patterns at the positions of the organs, which strongly suggests that the role of auxin in the floral meristem is similar to the role it plays in the shoot apical meristem. This is the basis for a simulation study of auxin transport through a growing floral meristem, which may answer the question whether auxin transport can in itself be responsible for the typical whorled floral pattern. We combined a cellular growth model for the meristem with a polar auxin transport model. The model predicts that sepals are initiated by auxin maxima arising early during meristem outgrowth. These form a pre-pattern relative to which a series of smaller auxin maxima are positioned, which partially overlap with the anlagen of petals, stamens, and carpels. We adjusted the model parameters corresponding to properties of floral mutants and found that the model predictions agree with the observed mutant patterns. The predicted timing of the primordia outgrowth and the timing and positioning of the sepal primordia show remarkable similarities with a developing flower in nature.
Full Text Available Abstract Background Sexually deceptive orchids of the genus Ophrys attract their pollinators, male insects, on a highly specific basis through the emission of odour blends that mimic the female sex pheromone of the targeted species. In this study, we have investigated a contact site between Ophrys arachnitiformis and O. lupercalis, two sympatric orchid species that are usually reproductively isolated via the exploitation of different pollinator "niches", but occasionally hybridise despite their apparent combination of ethological and mechanical isolation barriers. In particular, we have investigated the extent to which these Ophrys hybrids generate "emergent" combinations (i.e. novel and unpredictable from the parents' phenotypes of floral traits, and how these phenotypic novelties, particularly the odour blends emitted by the flower, could facilitate the invasion of a novel pollinator "niche" and induce the rapid formation of reproductive isolation, a prerequisite for adaptive evolutionary divergence. Results Our chemical analyses of floral scents show that the Ophrys F1 hybrids investigated here produce more compounds, significantly different ratios (% of odour compounds in the total blend, as well as new compounds in their floral odour compared to their progenitors. When tested for their attractiveness to the pollinator of each parent orchid species, we found that floral scent extracts of the hybrids triggered less inspecting flights and contacts by the male bees with the scented dummy than those of the parental orchid species. However, a series of additional behavioural bioassays revealed that the novel floral scent of the hybrids was significantly more attractive than either of the two parents to a pollinator species not initially involved in the pollination of any of the parent Ophrys species. Conclusions Collectively, our results illustrate that the process of hybridisation can lead to the generation of evolutionary novelties, and that
LÚCIA HELENA PIEDADE KIILL
Full Text Available ABSTRACT Floral morphology and biology are important characteristics for plant-pollinator interactions and may influence the behavior of these agents. This study aimed to determine which floral attributes of different melon hybrids influence this interaction and, consequently, their attractiveness in simultaneous crops. The study was conducted in the region of Petrolina, State of Pernambuco (PE/Juazeiro, State of Bahia (BA and Mossoró, State of Rio Grande do Norte (RN, in areas with the following melon hybrids: Yellow type, Piel de Sapo, Cantaloupe and Galia. For studies on floral morphology and biology, hermaphrodites and male flowers of each hybrid were analyzed for their size and nectar chamber size, pollen and nectar production, anthesis time and flower lifespan. Floral visitors were observed simultaneously in hybrids of three types of melon, from 5:00 a.m. to 6:00 p.m., in the two study sites. Evaluations of the corolla diameter and flower height indicated that the hermaphrodite flowers were larger in size than male flowers in all types of melon investigated, in both study sites. As for nectar chamber, male flowers are larger in width, but smaller in height, compared to hermaphrodite flowers. Regarding the volume of nectar, differences were found between floral types for the hybrids evaluated, in the two study sites; the hermaphrodite flowers produced 2-7 times more nectar than male flowers in all studied hybrids. Observations of visits of Apis mellifera to areas with simultaneous flowering of the three types of melon demonstrated differences in the frequency of visits between hybrids, floral type and foraged resource. Flowers of the hybrids Piel de Sapo and Cantaloupe exhibited larger corolla diameter, larger dimensions of the nectar chamber and greater supply of resources for foraging, which could explain the higher number of visits of bees to their flowers in the sites studied.
Stefanaki, Anastasia; Kantsa, Aphrodite; Tscheulin, Thomas; Charitonidou, Martha; Petanidou, Theodora
The architectural complexity of flower structures (hereafter referred to as floral complexity) may be linked to pollination by specialized pollinators that can increase the probability of successful seed set. As plant-pollinator systems become fragile, a loss of such specialized pollinators could presumably result in an increased likelihood of pollination failure. This is an issue likely to be particularly evident in plants that are currently rare. Using a novel index describing floral complexity we explored whether this aspect of the structure of flowers could be used to predict vulnerability of plant species to extinction. To do this we defined plant vulnerability using the Red Data Book of Rare and Threatened Plants of Greece, a Mediterranean biodiversity hotspot. We also tested whether other intrinsic (e.g. life form, asexual reproduction) or extrinsic (e.g. habitat, altitude, range-restrictedness) factors could affect plant vulnerability. We found that plants with high floral complexity scores were significantly more likely to be vulnerable to extinction. Among all the floral complexity components only floral symmetry was found to have a significant effect, with radial-flower plants appearing to be less vulnerable. Life form was also a predictor of vulnerability, with woody perennial plants having significantly lower risk of extinction. Among the extrinsic factors, both habitat and maximum range were significantly associated with plant vulnerability (coastal plants and narrow-ranged plants are more likely to face higher risk). Although extrinsic and in particular anthropogenic factors determine plant extinction risk, intrinsic traits can indicate a plant's proneness to vulnerability. This raises the potential threat of declining global pollinator diversity interacting with floral complexity to increase the vulnerability of individual plant species. There is potential scope for using plant-pollinator specializations to identify plant species particularly at
Bunya-atichart, K.; Ketsa, S.; Doorn, van W.G.
We studied the abscission of floral buds and open flowers in cut Dendrobium inflorescences. Abscission of floral buds was high and sensitive to ethylene in all cultivars studied. Many open flowers abscised in most cultivars, but cv. Willie exhibited only small amount of floral fall and cv. Miss Teen
Full Text Available Stamen movements can be understood as a mechanism influencing pollen presentation and increasing outbreeding success of hermaphroditic flowers via optimized male function. In this study we experimentally analyzed the factors regulating autonomous and thigmonastic (triggered by flower visitors stamen movements in eight species of Loasaceae. Both types of stamen movements are positively influenced by light and temperature and come to a virtual standstill in the dark and at low temperatures (12°C. Pollen presentation is thus discontinued during periods where pollinators are not active. Overall stamen presentation increases with increasing flower age. Contrary to expectation, no geometrical correlation between the floral scale stimulated and the stamen fascicle reacting exists, indicating that the stimulus is transmitted over the receptacle and stamen maturation dictates which and how many stamens react. Thigmonastic stamen presentation is dramatically accelerated compared to autonomous movement (3-37 times, indicating that the rate of stamen maturation can be adjusted to different visitation schedules. Flowers can react relatively uniformly down to stimulation intervals of 10-15 min., consistently presenting comparable numbers of stamens in the flower c. 5 min. after the stimulus and can thus keep the amount of pollen presented relatively constant even under very high visitation frequencies of 4-6 visits/h. Thigmonastic pollen presentation dramatically reduces the overall duration of the staminate phase (to 1/3(rd in Nasa macrothyrsa. Similarly, the carpellate phase is dramatically reduced after pollination, down to 1 d from 4 d. Overall flower longevity is reduced by more than 2/3(rds under high visitation rates (<3 d versus 10 d under visitor exclusion and depleted and pollinated flowers are rapidly removed from the pool. Complex floral behaviour in Loasaceae thus permits a near-total control over pollen dispensation schedules and floral
Zhao, Yan-Hui; Ren, Zong-Xin; Lázaro, Amparo; Wang, Hong; Bernhardt, Peter; Li, Hai-Dong; Li, De-Zhu
How floral traits and community composition influence plant specialization is poorly understood and the existing evidence is restricted to regions where plant diversity is low. Here, we assessed whether plant specialization varied among four species-rich subalpine/alpine communities on the Yulong Mountain, SW China (elevation from 2725 to 3910 m). We analyzed two factors (floral traits and pollen vector community composition: richness and density) to determine the degree of plant specialization across 101 plant species in all four communities. Floral visitors were collected and pollen load analyses were conducted to identify and define pollen vectors. Plant specialization of each species was described by using both pollen vector diversity (Shannon's diversity index) and plant selectiveness (d' index), which reflected how selective a given species was relative to available pollen vectors. Pollen vector diversity tended to be higher in communities at lower elevations, while plant selectiveness was significantly lower in a community with the highest proportion of unspecialized flowers (open flowers and clusters of flowers in open inflorescences). In particular, we found that plant species with large and unspecialized flowers attracted a greater diversity of pollen vectors and showed higher selectiveness in their use of pollen vectors. Plant species with large floral displays and high flower abundance were more selective in their exploitation of pollen vectors. Moreover, there was a negative relationship between plant selectiveness and pollen vector density. These findings suggest that flower shape and flower size can increase pollen vector diversity but they also increased plant selectiveness. This indicated that those floral traits that were more attractive to insects increased the diversity of pollen vectors to plants while decreasing overlap among co-blooming plant species for the same pollen vectors. Furthermore, floral traits had a more important impact on the
Le Borgne, R; Schmidt, A; Mauxion, F; Griffiths, G; Hoflack, B
In mammalian cells, clathrin-coated vesicles mediate transport of the lysosomal enzyme receptors from the trans-Golgi network to the endocytic pathway. A critical step of this process is the recruitment of Golgi-specific adaptors onto Golgi membranes for efficient clathrin polymerization. An in vitro assay was used here to quantitate this event in streptolysin-O-permeabilized NRK cells. At 37 degrees C, these interactions are cytosol- and energy-dependent, sensitive to GTP gamma S (guanosine 5'-O-(thiotriphosphate)) and brefeldin A. We report that Golgi-specific adaptor binding is enhanced in mannose 6-phosphate/insulin-like growth factor II (IGF II) receptor-overexpressing cells and reduced in mannose 6-phosphate receptor-deficient cells. Furthermore, adaptor binding is partially inhibited after addition of soluble cytoplasmic domains of the mannose 6-phosphate/IGF II receptor. Almost complete inhibition is only observed when this domain is phosphorylated on serines 2421 and 2492, a major modification acquired during exit of the receptor from the Golgi. These results show that the mannose 6-phosphate/IGF II receptor is part of the components that recruit the Golgi-specific adaptors and that its phosphorylation is an important feature for high affinity interactions with sorting components.
Iwaki, Shoko; Spicka, Jiri; Tkaczyk, Christine
The transmembrane adaptor protein (TRAP), NTAL, is phosphorylated in mast cells following FcvarepsilonRI aggregation whereby it cooperates with LAT to induce degranulation. The Kit ligand, stem cell factor (SCF), enhances antigen-induced degranulation and this also appears to be NTAL-dependent. H...
Richard B Tunnicliffe
Full Text Available The essential herpesvirus adaptor protein HVS ORF57, which has homologs in all other herpesviruses, promotes viral mRNA export by utilizing the cellular mRNA export machinery. ORF57 protein specifically recognizes viral mRNA transcripts, and binds to proteins of the cellular transcription-export (TREX complex, in particular ALYREF. This interaction introduces viral mRNA to the NXF1 pathway, subsequently directing it to the nuclear pore for export to the cytoplasm. Here we have used a range of techniques to reveal the sites for direct contact between RNA and ORF57 in the absence and presence of ALYREF. A binding site within ORF57 was characterized which recognizes specific viral mRNA motifs. When ALYREF is present, part of this ORF57 RNA binding site, composed of an α-helix, binds preferentially to ALYREF. This competitively displaces viral RNA from the α-helix, but contact with RNA is still maintained by a flanking region. At the same time, the flexible N-terminal domain of ALYREF comes into contact with the viral RNA, which becomes engaged in an extensive network of synergistic interactions with both ALYREF and ORF57. Transfer of RNA to ALYREF in the ternary complex, and involvement of individual ORF57 residues in RNA recognition, were confirmed by UV cross-linking and mutagenesis. The atomic-resolution structure of the ORF57-ALYREF interface was determined, which noticeably differed from the homologous ICP27-ALYREF structure. Together, the data provides the first site-specific description of how viral mRNA is locked by a herpes viral adaptor protein in complex with cellular ALYREF, giving herpesvirus access to the cellular mRNA export machinery. The NMR strategy used may be more generally applicable to the study of fuzzy protein-protein-RNA complexes which involve flexible polypeptide regions.
Full Text Available The floral biology of three weeds, Ipomoea cairica, I. grandifolia and I. nil (Convolvulaceae, was studied in Botucatu and Jaboticabal, São Paulo, in southeastern Brazil. The three species are melittophilous, with a varied set of floral visitors, but with some overlapping. Cluster analysis using Jacquard similarity index indicated a greater similarity among different plant species in the same locality than among the populations at different places, in relation to floral visitor sets. The promiscuous and opportunistic features of the flowers were shown, with such type of adaptation to pollination being advantageous to weeds since pollinator availability is unpredictable at ruderal environments.A biologia floral de Ipomoea cairica, I. grandifolia e I. nil - plantas daninhas da família Convolvulaceae - foi estudada em Botucatu e Jaboticabal, Estado de São Paulo, Brasil. As três espécies são melitófilas, apresentando conjuntos de visitantes florais bastante diversificados, embora haja alguma sobreposição entre eles. Com relação aos visitantes florais, a análise de agrupamento, empregando-se o índice de similaridade de Jaccard, indicou maior similaridade entre diferentes espécies de Ipomoea ocorrentes no mesmo local do que entre populações da mesma espécie em diferentes localidades. O caráter promíscuo e oportunista da adaptação à polinização, presente nessas espécies, foi demonstrado, sendo essa adaptação vantajosa para plantas daninhas, uma vez que em ambientes ruderais a disponibilidade de polinizadores é imprevisível.
Dynactin, a large multiprotein complex, binds with the cytoplasmic dynein-1 motor and various adaptor proteins to allow recruitment and transportation of cellular cargoes toward the minus end of microtubules. The structure of the dynactin complex is built around an actin-like minifilament with a defined length, which has been visualized in a high-resolution structure of the dynactin filament determined by cryo-electron microscopy (cryo-EM). To understand the energetic basis of dynactin filament assembly, we used molecular dynamics simulation to probe the intersubunit interactions among the actin-like proteins, various capping proteins, and four extended regions of the dynactin shoulder. Our simulations revealed stronger intersubunit interactions at the barbed and pointed ends of the filament and involving the extended regions (compared with the interactions within the filament), which may energetically drive filament termination by the capping proteins and recruitment of the actin-like proteins by the extended regions, two key features of the dynactin filament assembly process. Next, we modeled the unknown binding configuration among dynactin, dynein tails, and a number of coiled-coil adaptor proteins (including several Bicaudal-D and related proteins and three HOOK proteins), and predicted a key set of charged residues involved in their electrostatic interactions. Our modeling is consistent with previous findings of conserved regions, functional sites, and disease mutations in the adaptor proteins and will provide a structural framework for future functional and mutational studies of these adaptor proteins. In sum, this study yielded rich structural and energetic information about dynactin and associated adaptor proteins that cannot be directly obtained from the cryo-EM structures with limited resolutions.
Full Text Available Mini chromosome maintenance 1, agamous, deficiens, and serum response factor (MADS-box genes are transcription factors which play fundamental roles in flower development and regulation of floral organ identity. However, till date, identification and functions of MADS-box genes remain largely unclear in Phyllostachys edulis. In view of this, we performed a whole-genome survey and identified 34 MADS-box genes in P. edulis, and based on phylogeny, they were classified as MIKCC, MIKC∗, Mα, and Mβ. The detailed analysis about gene structure and motifs, phylogenetic classification, comparison of gene divergence and duplication are provided. Interestingly, expression patterns for most genes were found similar to those of Arabidopsis and rice, indicating that the well-established ABCDE model can be applied to P. edulis. Moreover, we overexpressed PheMADS15, an AP1-like gene, in Arabidopsis, and found that the transgenic plants have early flowering phenotype, suggesting that PheMADS15 might be a regulator of flowering transition in P. edulis. Taken together, this study provides not only insightful comprehension but also useful information for understanding the functions of MADS-box genes in P. edulis.
In entomogamous plants, the presence and function of floral secretory structures, whose main role is to attract pollinators, is strictly associated with the pollination ecology and hence the reproductive success of the plant. The aims of the present paper were to analyse the micromorphology and anatomy of flower nectaries and stigmas in Viburnum opulus and V. lantana and to determine the function and microstructure of inflorescence trichomes in both taxa using light and scanning electron microscopy as well as histochemical assays. It was found that stigmas were formed by papillae, which contained lipids, polysaccharides, tannins, and pigments. Stigmatic secretion proceeded via cuticular pores. Floral nectaries formed a thick layer around the styles, and nectar was secreted through numerous nectarostomata. There were no traces of vascular bundles penetrating the nectary tissue. In turn, numerous tannin deposits were observed in the cells of the glandular parenchyma. Pedicels, hypanthia, and bracts had mainly peltate and capitate glandular trichomes as well as stellate non-glandular trichomes (in V. lantana). The trichomes were shown to contain lipids, mucilage, and tannins. Many similarities in the flower and nectaries microstructure and considerable heterogeneity were observed in the examined Viburnum species. Knowledge of the microstructural characteristics of flowers, nectaries, and trichomes may be important for the phylogenesis and taxonomy of the genus Viburnum and the family Adoxaceae. Additionally, floral and nectaries features are helpful in assessment of the relatedness between taxa and provide better understanding of the floral biology and pollination ecology.
de Viana, M L; Ortega Baes, P; Saravia, M; Badano, E I; Schlumpberger, B
Many columnar cacti are bat pollinated. It has been suggested that this kind of pollination would be more important in tropical than in temperate regions where flowers are open only one night. Thrichocereus pasacana produces big and resistant white flowers. We analyzed flower characteristics, floral cycle, stigmatic receptivity, nectar production, pollen presence and floral visitors in a T. pasacana population at National Park Los Cardones (Salta, Argentina) in November 1997. Flower features were constant between individuals of the population. Flowers start opening at evening and anthesis time is from 18 to 40 hs. The estigma was receptive throughout the floral cycle. Anther dehiscence occurs with flower opening. Nectar production was highest between 18 to 24 hs. Although T. pasacana are open during the night, floral visitors are diurnal. The most frequent was Xylocopa sp. In the study area, nectarivorous bats were not detected. The morphological features of T. pasacana flowers were similar but bigger compared to other columnar cacti. Anthesis time was also longer while nectar production was lower. T. pasacana pollination at National Park Los Cardones is done by bees.
Wäckers, F.L.; Bonifay, C.
Plants employ nectar for two distinct functions. Floral nectar has traditionally been viewed in the context of pollination. Extrafloral nectar on the other hand, can act as an indirect defense, allowing the plant to recruit predators and parasitoids. Whereas this makes for a clear-cut
Karron, Jeffrey D; Mitchell, Randall J
The number of flowers blooming simultaneously on a plant may have profound consequences for reproductive success. Large floral displays often attract more pollinator visits, increasing outcross pollen receipt. However, pollinators frequently probe more flowers in sequence on large displays, potentially increasing self-pollination and reducing pollen export per flower. To better understand how floral display size influences male and female fitness, we manipulated display phenotypes and then used paternity analysis to quantify siring success and selfing rates. To facilitate unambiguous assignment of paternity, we established four replicate (cloned) arrays of Mimulus ringens, each consisting of genets with unique combinations of homozygous marker genotypes. In each array, we trimmed displays to two, four, eight or 16 flowers. When fruits ripened, we counted the number of seeds per fruit and assigned paternity to 1935 progeny. Siring success per flower declined sharply with increasing display size, while female success per flower did not vary with display. The rate of self-fertilization increased for large floral displays, but siring losses due to geitonogamous pollen discounting were much greater than siring gains through increased self-fertilization. As display size increased, each additional seed sired through geitonogamous self-pollination was associated with a loss of 9·7 seeds sired through outcrossing. Although total fitness increased with floral display size, the marginal return on each additional flower declined steadily as display size increased. Therefore, a plant could maximize fitness by producing small displays over a long flowering period, rather than large displays over a brief flowering period.
Reproductive biology and patterns of plant-pollinator interaction are fundamental to gene flow, diversity and evolutionary success of plants. Consequently, we examined the magnitude of insect-plant interaction based on the dynamics of breeding systems and floral biology and their effects on pollination intensity, fruit and ...
Goldbach, R.; Kuo, G.
The International Symposium on Tospoviruses and Thrips of Floral and Vegetable Crops, held 7–10 November 1995 in Taiwan, attracted scientists active in virology, entomology, and resistance breeding. This blend of expertise provided much new information. The last international meeting on tospoviruses
Meulen-Muisers, van der J.J.M.; Oeveren, van J.C.; Sandbrink, J.M.; Tuyl, van J.M.
Floral bud abortion was found to be an undesirable source of non-genetic variation in breeding trials directed on the improvement of individual flower longevity in Asiatic hybrid lilies. It increased the longevity of the remaining flowers of the inflorescence. A similar response was found after
Waelti Marc O
Full Text Available Abstract Background Sexual selection theory predicts that males are limited in their reproductive success by access to mates, whereas females are more limited by resources. In animal-pollinated plants, attraction of pollinators and successful pollination is crucial for reproductive success. In dioecious plant species, males should thus be selected to increase their attractiveness to pollinators by investing more than females in floral traits that enhance pollinator visitation. We tested the prediction of higher attractiveness of male flowers in the dioecious, moth-pollinated herb Silene latifolia, by investigating floral signals (floral display and fragrance and conducting behavioral experiments with the pollinator-moth, Hadena bicruris. Results As found in previous studies, male plants produced more but smaller flowers. Male flowers, however, emitted significantly larger amounts of scent than female flowers, especially of the pollinator-attracting compounds. In behavioral tests we showed that naïve pollinator-moths preferred male over female flowers, but this preference was only significant for male moths. Conclusion Our data suggest the evolution of dimorphic floral signals is shaped by sexual selection and pollinator preferences, causing sexual conflict in both plants and pollinators.
Amini, Safoora; Alias, Halimah; Aizat-Juhari, Mohd Afiq; Mat-Isa, Mohd-Noor; Adam, Jumaat Haji; Goh, Hoe-Han; Wan, Kiew-Lian
Rafflesia cantleyi, known as one of the world's largest flowers, is a specialised holoparasite due to dramatic morphological modifications. It possesses highly reduced vegetative structure and only appears as a flower for sexual reproduction. Moreover, it has an unusual life cycle in that its floral bud development takes up to nine months. In order to fully understand the highly modified floral organ structure and long life cycle of R. cantleyi, we used Illumina sequencing technology (HiSeq) for sequence generation followed by de novo assembly of sequence reads. We obtained the RNA-seq data from three different stages of floral bud, representing the early, mid and advanced developmental stages. These data are available via BioProject accession number PRJNA378435. More than 10.3 Gb raw sequence data were generated, corresponding to 102,203,042 raw reads. Following removal of low-quality reads and trimming of adapter sequences, a total of 91,638,836 reads were obtained. De novo assembly of these sequences using Trinity resulted in 89,690 unique transcripts with an N50 of 1653 bp. The obtained transcriptomic data will be useful for further study to understand the molecular interactions that result in R. cantleyi floral development.
Barabé, Denis; Lacroix, Christian
The floral development of Dieffenbachia seguine (N. J. Jacquin) Schott is analysed in relation to the molecular phylogeny of the Spathicarpae by Cusimano et al. (Am J Bot 98:654-668, 2011). The initiation of discoid floral primordia occurs acropetally on the surface of the spadix. Female flowers, atypical bisexual flowers, sterile male flowers, and male flowers share the same phyllotactic spirals on the spadix. Four or five stamen primordia are initiated simultaneously on the periphery of the male floral meristem. During early stages of stamen initiation, individual stamen primordia are connate at their base. In a synandrium, stamen fusion occurs very early during their developmental cycle with the stamens being already united laterally when longitudinal elongation occurs. The staminodes are also initiated on the periphery of the discoid floral primordium, and their number varies from four to six. The development of the fused staminodes will eventually form a longitudinal cavity in the center of the mature synandrode. The atypical flowers located in the intermediate zone range in morphology from aborted female flowers to rudimentary sterile male flowers with incomplete staminodes. The development of the female flower of Dieffenbachia Schott presents some similarities with atypical bisexual flowers of Cercestis Schott representing one of three types of aberrant flower forms in the family. From a developmental point of view and in the context of a phylogeny of the group, we believe that the presence of staminodes in the female zone constitutes a plesiomorphy in the tribe Spathicarpeae.
Gettys, Lyn A; Wofford, David S
Pickerelweed (Pontederia cordata L.) is a diploid (2n = 2x = 16) tristylous aquatic perennial. Populations usually contain 3 floral morphs that differ reciprocally in style length and anther height (referred to as the long-, mid-, and short-styled morphs, hereafter L-, M-, and S-morphs). The floral polymorphism promotes disassortative mating among the 3 floral morphs and is maintained in populations by negative frequency-dependent selection. The objective of this study was to determine the number of loci, number of alleles, and gene action controlling floral morph in pickerelweed. Three parental lines (one each of the L-, M-, and S-morph) were used to create S1 and F1 populations. F2 populations were produced through self-pollination of F1 plants. Progeny ratios of S1, F1, and F2 generations revealed that tristyly is controlled by 2 diallelic loci (S and M) with dominant gene action. The S locus is epistatic to the M locus, with the S-morph produced by plants with the dominant S allele (genotype S _ _ _). Plants with recessive alleles at the S locus were either L-morph (ssmm) or M-morph (ssM_). The results of this experiment demonstrate that the inheritance of tristyly in pickerelweed is the same as previously reported for several tristylous species in the Lythraceae and Oxalidaceae.
Shiv Narayan Amit Kumar
Full Text Available Recently, natural dyes and pigments gain more importance in food and textile industries because of their non toxic and eco friendly characteristics. Bougainvillea glabra floral bracts are rich in betalain pigments which can be used as a dye in sensitized solar cells, medicinal and food applications. The aim of this study was to optimize the natural pigment extraction from the floral bracts by response surface methodology. Central composite design (CCD of response surface methodology (RSM was applied to evaluate the optimal conditions of three process variables namely mass of floral bracts (g, extraction time (h and temperature (°C studied at five levels. Mass of bracts and extraction time were found statistically significant in the process and correlation coefficient (R2 value of 0.96 showed that model was well fitted with the experimental values. The optimum process conditions were found to be mass of floral bracts: 3 g, contact time: 6 h and extraction temperature: 22.5 °C with maximum absorbance of 9.18. Response surface methodology was performed well to identify the optimal levels of extraction process variables and the validation of predicted model was fitted 99.76% with the experimental results conducted at the optimum conditions. Fourier Transform Infrared Spectroscopy was also confirmed the presence of betalain pigment by identifying the major functional groups.
Palmer-Young, E C; Sadd, B M; Adler, L S
Repeated exposure to inhibitory compounds can drive the evolution of resistance, which weakens chemical defence against antagonists. Floral phytochemicals in nectar and pollen have antimicrobial properties that can ameliorate infection in pollinators, but evolved resistance among parasites could diminish the medicinal efficacy of phytochemicals. However, multicompound blends, which occur in nectar and pollen, present simultaneous chemical challenges that may slow resistance evolution. We assessed evolution of resistance by the common bumble bee gut parasite Crithidia bombi to two floral phytochemicals, singly and combined, over 6 weeks (~100 generations) of chronic exposure. Resistance of C. bombi increased under single and combined phytochemical exposure, without any associated costs of reduced growth under phytochemical-free conditions. After 6 weeks' exposure, phytochemical concentrations that initially inhibited growth by > 50%, and exceeded concentrations in floral nectar, had minimal effects on evolved parasite lines. Unexpectedly, the phytochemical combination did not impede resistance evolution compared to single compounds. These results demonstrate that repeated phytochemical exposure, which could occur in homogeneous floral landscapes or with therapeutic phytochemical treatment of managed hives, can cause rapid evolution of resistance in pollinator parasites. We discuss possible explanations for submaximal phytochemical resistance in natural populations. Evolved resistance could diminish the antiparasitic value of phytochemical ingestion, weakening an important natural defence against infection. © 2016 The Authors. Journal of Evolutionary Biology Published by John Wiley & Sons ltd on behalf of European Society for Evolutionary Biology.
The study of plant secondary chemistry has been essential in understanding plant consumption by herbivores. There is growing evidence that secondary compounds also occur in floral rewards, including nectar and pollen. Many pollinators are generalist nectar and pollen foragers and thus are exposed to...
Lawrence Stephen FAYEUN
Full Text Available Knowledge of floral biology is essential to crop improvement. Ten genotypes of fluted pumpkin (Telfairia occidentalis were observed for floral morphology, phenology and insect visitation for two consecutive years. Functional dioecy of fluted pumpkin was confirmed, whereas none of the studied genotypes was monoecious. Floral structures differed significantly among the genotypes. Both male and female flowers were symmetrical, pentasepalous, fimbriate and non-bright pentapetalous, but male flowers were more numerous. Male inflorescences emerged from 11 to 14 weeks after planting and the female flower buds appeared about 4 weeks later. The flowering period of the male flowers was longer than that of female flowers and both gender flowering periods coincided for a specific interval. It took between 11 to 14 days from bud initiation to anthesis and flowering ceased when there were occurrences of successful fruits set. In both gender flowers petals started unfurling at around 6.00 pm and full bloom was achieved by dawn, while petal shrivelled at sun set (between 6.30 pm to 7.30 pm. The anthers dehisced at anthesis of the male flowers; the pollen grains were whitish and sticky. Only the male flowers have nectar and pollen and this may explain infrequent female flowers visitation. Hover flies (Cheilosia species were the major floral visitors observed.
Laura A. Burkle; Justin B. Runyon
As diverse environmental changes continue to influence the structure and function of plant-pollinator interactions across spatial and temporal scales, we will need to enlist numerous approaches to understand these changes. Quantitative examination of floral volatile organic compounds (VOCs) is one approach that is gaining popularity, and recent work suggests that...
Pollinators together with other biotic and some abiotic factors can select for floral traits. However, variation in pollinator abundance over time and space can weaken such selection. In this study, we examined the variation in pollinator abundance over time and space in populations of the rocky mou...
This work aimed to study the chemical composition of essential oils and floral waters of Cymbopogon citratus (DC.) Stapf (Poaceae) from Senegal. The plants were collected in two different localities, Dakar and Kaolack. The extracts were obtained by steam distillation from both fresh and dried plants and analyses carried ...
This work aimed to study the chemical composition of essential oils and floral waters of Cymbopogon ... essential oil production. Within an international project designed to promote the production of essential oils in Senegal, several endemic plants among which C. citratus ..... the article; MBD participated on the writing of.
Full Text Available Hummingbird communities tend to respond to variation in resources, having a positive relationship between abundance and diversity of food resources and the abundance and/or diversity of hummingbirds. Here we examined the influence of floral resource availability, as well as seasonality and type of habitat on the composition of hummingbird species. The study was carried out in two habitats of eastern Brazilian mountaintops. A gradient representative of the structure of hummingbird community, based on species composition, was obtained by the ordination of samples using the method of non-metric multidimensional scaling. The composition of hummingbird species was influenced by the type of habitat and floral resource availability, but not by seasonality. Hummingbird communities differ between habitats mainly due to the relative abundance of hummingbird species. The variation in composition of hummingbird species with the variation in floral resource availability may be related to differences in feeding habits of hummingbirds. Hummingbird species with the longest bills visited higher proportions of ornithophilous species, while hummingbirds with shorter bills visited higher proportions of non-ornithophilous species. The results demonstrate that at local-scale the composition of hummingbird species is affected by the type of habitat and floral resources availability, but not by seasonality.
There is growing interest in IPM programs and habitat management to combat the decline in diversity of beneficial arthropods in agricultural landscapes caused by habitat simplification and intensive management practices. Addition of floral resources to the landscape can help offset these effects. We...
We cloned bde by positional cloning and found that it encodes zag3, a MADS-box transcription factor in the conserved AGL6 clade. Mutants in the maize homolog of AGAMOUS, zag1, have a subset of bde floral defects. bde; zag1 double mutants have a severe ear phenotype, not observed in either single m...
Soper Gorden, Nicole L; Adler, Lynn S
While the effect of abiotic factors on leaf herbivory is well known, the relative importance of abiotic conditions influencing both mutualists and antagonists is less well understood. Species interactions could enhance or reduce the direct effects of abiotic factors, depending on how mutualists and antagonists respond to abiotic conditions. We manipulated soil nutrients and shade in a factorial design and measured soil moisture in the annual Impatiens capensis. We then measured interactions with mutualists (two pollinating species) and antagonists (herbivores, florivores, nectar thieves, and flower bud gallers), as well as plant growth, floral rewards, and plant reproduction. Fertilizer increased plant growth, floral attractiveness, mutualist and antagonist interactions, and plant reproduction. Shade had no effects, and soil moisture was negatively associated with plant growth and reproduction. All effects were additive. Mutualist and antagonist floral interactions both increased on fertilized plants, but antagonists increased at a greater rate, leading to a larger ratio of antagonist to mutualist interactions on fertilized plants. Despite having more antagonists, fertilized plants still had significantly higher reproduction, suggesting higher tolerance to antagonists. Abiotic effects can have consistent effects on antagonists and mutualists, and on both floral and leaf antagonists. However, tolerance to antagonisms increased in favorable conditions. Thus, the direct positive effects of favorable abiotic conditions on plants outweighed negative indirect effects via increased antagonisms, which may lead to selection to grow in high-nutrient microsites in spite of increased herbivory.
Tsala Apopka Lake, in west-central Florida, has an area of about 19,000 acres and is divided into three water-management pools, with the Floral City Pool, the most upgradient. The Floral City Pool, which has a surface area of approximately 4,750 acres, contains an extensive combination of lakes, wetlands, and connecting canals. The Pool receives inflow from the Withlacoochee River through two canals. Outflow is through one manmade canal and one natural slough. Canal flow is partially controlled by manmade structures. A cumulative deficit of 19.4 inches of rainfall from August 1984 through May 1985 reduced surface-water inflow to the Floral City Pool to about 0.5 cu ft/sec by May 1985. During May 1985, pool levels declined approximately 0.04 ft/day. By the end of May, there was no observable outflow. From June 1985 through September 1985, 39.8 inches of rainfall caused above-average inflow to the Floral City Pool and a pool-level increase of 6.2 ft. The inflow of 340 CFS nearly equaled the outflow of 338 CFS by the end of September. (USGS)
Rodrigues, L C; Rodrigues, M
Hummingbird communities tend to respond to variation in resources, having a positive relationship between abundance and diversity of food resources and the abundance and/or diversity of hummingbirds. Here we examined the influence of floral resource availability, as well as seasonality and type of habitat on the composition of hummingbird species. The study was carried out in two habitats of eastern Brazilian mountaintops. A gradient representative of the structure of hummingbird community, based on species composition, was obtained by the ordination of samples using the method of non-metric multidimensional scaling. The composition of hummingbird species was influenced by the type of habitat and floral resource availability, but not by seasonality. Hummingbird communities differ between habitats mainly due to the relative abundance of hummingbird species. The variation in composition of hummingbird species with the variation in floral resource availability may be related to differences in feeding habits of hummingbirds. Hummingbird species with the longest bills visited higher proportions of ornithophilous species, while hummingbirds with shorter bills visited higher proportions of non-ornithophilous species. The results demonstrate that at local-scale the composition of hummingbird species is affected by the type of habitat and floral resources availability, but not by seasonality.
El-Sayed, A M; Byers, J A; Manning, L M; Jürgens, A; Mitchell, V J; Suckling, D M
The flowers of Canada thistle, Cirsium arvense (L.), attract a wide range of insects, including pollinators and herbivorous species. This attraction is primarily mediated by floral odor, which offers potential for developing generic insect attractants based on odor. In this study, we have analyzed the chemical composition of the volatiles produced by Canada thistle flowers. Nineteen floral compounds were identified in the headspace, including phenylacetaldehyde (55%), methyl salicylate (14%), dimethyl salicylate (8%), pyranoid linalool oxide (4.5%), and benzaldehyde (3.5%). Other minor compounds include benzyl alcohol, methylbenzoate, linalool, phenylethyl alcohol, furanoid linalool oxide, p-anisaldehyde, 2,6-dimethyl-1,3,5,7-octatetraene, benzylacetate, benzyl tiglate, (E,E)-alpha-farnesene, benzyl benzoate, isopropyl myristate, and 2-phenylethyl ester benzoic acid. The relative attractiveness of various doses of the main floral volatile compound phenylacetaldehyde (i.e., 10, 100, 200, and 400 mg) was tested for insect attraction. Both the total catch and the biodiversity of insect species trapped increased as the loading of phenylacetaldehyde increased. Volatiles were chosen from the odors from the flowers of Canada thistle and formulated and tested in the field. An 11-component blend was the most attractive of several floral blends tested. These findings indicate that chemical components of flower odors of Canada thistle can serve as a generic insect attractant for monitoring of invasive pest species.
Oct 18, 2012 ... Schemske DW, Horvitz CC (1989). Temporal variation in selection on a floral character. Evolution 43:461-465. Smith-Ramirez C, Martinez P, Nunez M, Gonzalez C, Armesto JJ. (2005). Diversity, flower visitation frequency and generalism of pollinators in temperate rain forest of Chiloe Island, Chile. Bot. J.
Alva, Orlando; Roa-Roco, Rosa Nair; Pérez-Díaz, Ricardo; Yáñez, Mónica; Tapia, Jaime; Moreno, Yerko; Ruiz-Lara, Simón; González, Enrique
Parthenocarpic fruit development (PFD) reduces fruit yield and quality in grapevine. Parthenocarpic seedless berries arise from fruit set without effective fertilization due to defective pollen germination. PFD has been associated to micronutrient deficiency but the relation of this phenomenon with pollen polymorphism has not been reported before. In this work, six grapevine cultivars with different tendency for PFD and grown under micronutrient-sufficient conditions were analyzed to determine pollen structure and germination capability as well as PFD rates. Wide variation in non-germinative abnormal pollen was detected either among cultivars as well as for the same cultivar in different growing seasons. A straight correlation with PFD rates was found (R2 = 0.9896), suggesting that natural parthenocarpy is related to defective pollen development. Such relation was not observed when PFD was analyzed in grapevine plants exposed to exogenous gibberellin (GA) or abscissic acid (ABA) applications at pre-anthesis. Increase (GA treatment) or reduction (ABA treatment) in PFD rates without significative changes in abnormal pollen was determined. Although these plants were maintained at sufficient boron (B) condition, a down-regulation of the floral genes VvBOR3 and VvBOR4 together with a reduction of floral B content in GA-treated plants was established. These results suggest that impairment in B mobility to reproductive tissues and restriction of pollen tube growth could be involved in the GA-induced parthenocarpy.
Full Text Available Parthenocarpic fruit development (PFD reduces fruit yield and quality in grapevine. Parthenocarpic seedless berries arise from fruit set without effective fertilization due to defective pollen germination. PFD has been associated to micronutrient deficiency but the relation of this phenomenon with pollen polymorphism has not been reported before. In this work, six grapevine cultivars with different tendency for PFD and grown under micronutrient-sufficient conditions were analyzed to determine pollen structure and germination capability as well as PFD rates. Wide variation in non-germinative abnormal pollen was detected either among cultivars as well as for the same cultivar in different growing seasons. A straight correlation with PFD rates was found (R2 = 0.9896, suggesting that natural parthenocarpy is related to defective pollen development. Such relation was not observed when PFD was analyzed in grapevine plants exposed to exogenous gibberellin (GA or abscissic acid (ABA applications at pre-anthesis. Increase (GA treatment or reduction (ABA treatment in PFD rates without significative changes in abnormal pollen was determined. Although these plants were maintained at sufficient boron (B condition, a down-regulation of the floral genes VvBOR3 and VvBOR4 together with a reduction of floral B content in GA-treated plants was established. These results suggest that impairment in B mobility to reproductive tissues and restriction of pollen tube growth could be involved in the GA-induced parthenocarpy.
Davies, Kevin L; Stpiczyńska, Małgorzata; Rawski, Michał
Recently, molecular approaches have been used to investigate the phylogeny of subtribe Oncidiinae, resulting in the re-alignment of several of its genera. Here, a description is given of the structure of the floral elaiophores (oil glands) of four species formerly assigned to Oncidium Sw. Those of Vitekorchis excavata (Lindl.) Romowicz & Szlach., Cyrtochilum meirax (Rchb.f.) Dalström and a species of Oncidium displaying floral dimorphism, namely O. heteranthum Poepp. & Endl. var. album, are compared with that of Gomesa longipes (Lindl.) M.W. Chase & N.H. Williams, whose epithelial elaiophores are typical of many Oncidiinae, in order to extend our understanding of elaiophore diversity within this subtribe. Floral elaiophore structure was examined and compared at anthesis for all four species using light microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry. In all species investigated, with the exception of C. meirax, the floral elaiophore occurs on the labellar callus and is of the intermediate type, possessing both glabrous and trichomatous regions. By contrast, although all four species produce lipid secretions, C. meirax lacks an obvious elaiophore. In each case, the secretory tissue is represented by a single-layered epidermis of cuboidal cells (trichomatous and/or atrichomatous). Palisade cells are absent. The secretion may be wax- or oil-like and is usually produced by smooth endoplasmic reticulum (SER). However, in C. meirax, where rough endoplasmic reticulum (RER) predominates, oil accumulates as plastoglobuli within elaioplasts. These plastoglobuli are then discharged into the cytoplasm, forming oil bodies. In some species, oil usually accumulates within vesicles at the plasmalemma or in the periplasmic space before traversing the cell wall and accumulating beneath the cuticle, sometimes with distension of the latter. Gomesa longipes is unusual in its production of a heterogeneous secretion, whereas Vitekorchis
Reginato, Marcelo; Michelangeli, Fabián A
Putative processes related to floral diversification and its relation to speciation are still largely unaccounted for in the Melastomataceae. Leandra s.str. is one of the most diverse lineages of the Neotropical Miconieae and ranks among the ten most diverse groups in the Atlantic Forest. Here, we describe the floral diversity of this lineage in a continuous framework and address several questions related to floral evolution and putative developmental and environmental constraints in its morphology. The morphological data set includes individual size measurements and shape scores (from elliptical Fourier analysis) for hypanthia, petals, stamens and styles. We evaluate whether there is evidence of correlation among these floral structures, shifts and convergent patterns, and association of these traits with elevation. Leandra s.str. flower structures present a strong phylogenetic signal and tend to be conserved among close relatives. The extremes in flower regimes seem to be quite distinct, but non-overlapping discrete flower types are not observed. Overall, the morphology of Leandra s.str. floral structures is correlated, and anther colour and inflorescence architecture correlate with flower structures. Additionally, the rates of species diversification and morphological evolution are correlated in most clades. Although some flower regimes tend to occur in different elevational ranges, no significant association is observed. The general idea that hypanthium-ovary fusion is associated with fruit types in the Melastomataceae does not hold for Leandra s.str., where, instead, hypanthium-ovary fusion seems to be associated with anther shape. The lowest rate of flower morphological change, when compared with species diversification rates, is observed in the clade that possesses the most specialized flowers in the group. While stuck on a single general pollination system, Leandra s.str. seems to be greatly wandering around it, given the flower diversity and convergent
Ethan J Temeles
Full Text Available Optimal foraging models of floral divergence predict that competition between two different types of pollinators will result in partitioning, increased assortative mating, and divergence of two floral phenotypes. We tested these predictions in a tropical plant-pollinator system using sexes of purple-throated carib hummingbirds (Anthracothorax jugularis as the pollinators, red and yellow inflorescence morphs of Heliconia caribaea as the plants, and fluorescent dyes as pollen analogs in an enclosed outdoor garden. When foraging alone, males exhibited a significant preference for the yellow morph of H. caribaea, whereas females exhibited no preference. In competition, males maintained their preference for the yellow morph and through aggression caused females to over-visit the red morph, resulting in resource partitioning. Competition significantly increased within-morph dye transfer (assortative mating relative to non-competitive environments. Competition and partitioning of color morphs by sexes of purple-throated caribs also resulted in selection for floral divergence as measured by dye deposition on stigmas. Red and yellow morphs did not differ significantly in dye deposition in the competition trials, but differences in dye deposition and preferences for morphs when sexes of purple-throated caribs foraged alone implied fixation of one or the other color morph in the absence of competition. Competition also resulted in selection for divergence in corolla length, with the red morph experiencing directional selection for longer corollas and the yellow morph experiencing stabilizing selection on corolla length. Our results thus support predictions of foraging models of floral divergence and indicate that pollinator competition is a viable mechanism for divergence in floral traits of plants.
Baude, Mathilde; Kunin, William E.; Boatman, Nigel D.; Conyers, Simon; Davies, Nancy; Gillespie, Mark A. K.; Morton, R. Daniel; Smart, Simon M.; Memmott, Jane
There is considerable concern over declines in insect pollinator communities and potential impacts on the pollination of crops and wildflowers. Among the multiple pressures facing pollinators, decreasing floral resources due to habitat loss and degradation has been suggested as a key contributing factor. However, a lack of quantitative data has hampered testing for historical changes in floral resources. Here we show that overall floral rewards can be estimated at a national scale by combining vegetation surveys and direct nectar measurements. We find evidence for substantial losses in nectar resources in England and Wales between the 1930s and 1970s; however, total nectar provision in Great Britain as a whole had stabilized by 1978, and increased from 1998 to 2007. These findings concur with trends in pollinator diversity, which declined in the mid-twentieth century but stabilized more recently. The diversity of nectar sources declined from 1978 to 1990 and thereafter in some habitats, with four plant species accounting for over 50% of national nectar provision in 2007. Calcareous grassland, broadleaved woodland and neutral grassland are the habitats that produce the greatest amount of nectar per unit area from the most diverse sources, whereas arable land is the poorest with respect to amount of nectar per unit area and diversity of nectar sources. Although agri-environment schemes add resources to arable landscapes, their national contribution is low. Owing to their large area, improved grasslands could add substantially to national nectar provision if they were managed to increase floral resource provision. This national-scale assessment of floral resource provision affords new insights into the links between plant and pollinator declines, and offers considerable opportunities for conservation.
Gómez, J. M.; Muñoz-Pajares, A. J.; Abdelaziz, M.; Lorite, J.; Perfectti, F.
Background and Aims How generalist plants diverge in response to pollinator selection without becoming specialized is still unknown. This study explores this question, focusing on the evolution of the pollination system in the pollination generalist Erysimum mediohispanicum (Brassicaceae). Methods Pollinator assemblages were surveyed from 2001 to 2010 in 48 geo-referenced populations covering the entire geographic distribution of E. mediohispanicum. Bipartite modularity, a complex network tool, was used to find the pollination niche of each population. Evolution of the pollination niches and the correlated evolution of floral traits and pollination niches were explored using within-species comparative analyses. Key Results Despite being generalists, the E. mediohispanicum populations studied can be classified into five pollination niches. The boundaries between niches were not sharp, the niches differing among them in the relative frequencies of the floral visitor functional groups. The absence of spatial autocorrelation and phylogenetic signal indicates that the niches were distributed in a phylogeographic mosaic. The ancestral E. mediohispanicum populations presumably belonged to the niche defined by a high number of beetle and ant visits. A correlated evolution was found between pollination niches and some floral traits, suggesting the existence of generalist pollination ecotypes. Conclusions It is conjectured that the geographic variation in pollination niches has contributed to the observed floral divergence in E. mediohispanicum. The process mediating this floral divergence presumably has been adaptive wandering, but the adaptation to the local pollinator faunas has been not universal. The outcome is a landscape where a few populations locally adapted to their pollination environment (generalist pollination ecotypes) coexist with many populations where this local adaptation has failed and where the plant phenotype is not primarily shaped by pollinators. PMID
Gervasi, Daniel D L; Selosse, Marc-Andre; Sauve, Mathieu; Francke, Wittko; Vereecken, Nicolas J; Cozzolino, Salvatore; Schiestl, Florian P
Speciation is typically accompanied by the formation of isolation barriers between lineages. Commonly, reproductive barriers are separated into pre- and post-zygotic mechanisms that can evolve with different speed. In this study, we measured the strength of different reproductive barriers in two closely related, sympatric orchids of the Ophrys insectifera group, namely Ophrys insectifera and Ophrys aymoninii to infer possible mechanisms of speciation. We quantified pre- and post-pollination barriers through observation of pollen flow, by performing artificial inter- and intraspecific crosses and analyzing scent bouquets. Additionally, we investigated differences in mycorrhizal fungi as a potential extrinsic factor of post-zygotic isolation. Our results show that floral isolation mediated by the attraction of different pollinators acts apparently as the sole reproductive barrier between the two orchid species, with later-acting intrinsic barriers seemingly absent. Also, the two orchids share most of their fungal mycorrhizal partners in sympatry, suggesting little or no importance of mycorrhizal symbiosis in reproductive isolation. Key traits underlying floral isolation were two alkenes and wax ester, present predominantly in the floral scent of O. aymoninii . These compounds, when applied to flowers of O. insectifera , triggered attraction and a copulation attempt of the bee pollinator of O. aymoninii and thus led to the (partial) breakdown of floral isolation. Based on our results, we suggest that adaptation to different pollinators, mediated by floral scent, underlies species isolation in this plant group. Pollinator switches may be promoted by low pollination success of individuals in dense patches of plants, an assumption that we also confirmed in our study.
Nunes, Carlos E P; Wolowski, Marina; Pansarin, Emerson Ricardo; Gerlach, Günter; Aximoff, Izar; Vereecken, Nicolas J; Salvador, Marcos José; Sazima, Marlies
Floral volatile organic compounds (VOCs) play important roles in plant-pollinator interactions. We investigated the reproductive ecology and floral VOCs of Zygopetalinae orchids to understand the relationship between floral scents and pollinators. We performed focal observations, phenological censuses and breeding system experiments in eight species in southeast Brazil. Floral scents were collected and analysed using SPME/GC-MS. We performed multivariate analyses to group species according to affinities of their VOCs and define compounds associated to each plant. Dichaea cogniauxiana was pollinated by weevils which use their developing ovules, while D. pendula was pollinated by the same weevils and perfume-collecting male euglossine bees. The other species were deceit-pollinated by bees. Zygopetalum crinitum was pollinated by carpenter bees, while W. warreana, Z. mackayi and Z. maxillare were bumblebee-pollinated. The latter was also pollinated by Centris confusa. Breeding system varied widely with no association to any pollinator group. Most VOCs are common to other floral scents. Zygopetalum crinitum presented an exclusive blend of VOCs, mainly composed of benzenoids. The scents of Pabstia jugosa, Promenaea xanthina and the Zygopetalum spp. were similar. The bumblebee-pollinated species have flowering periods partially overlapped, thus neither phenology nor pollinators constitute hybridization barriers among these species. Euglossines are not the only pollinators of Zygopetalinae. Different VOCs, size and lifespan of flowers are associated with distinct pollinators. A distinctive VOC bouquet may determine specialisation in carpenter bees or male euglossines within bee-pollinated flowers. Finally, visitation of deceit-pollinated flowers by perfume-collecting euglossines allows us to hypothesise how pollination by this group of bees had evolved.
Prattes, M.; Loibl, M.; Zisser, G.; Luschnig, D.; Kappel, L.; Rossler, I.; Grassegger, M.; Hromic, A.; Krieger, E.; Gruber, K.; Pertschy, B.; Bergler, H.
AAA-ATPases fulfil essential roles in different cellular pathways and often act in form of hexameric complexes. Interaction with pathway-specific substrate and adaptor proteins recruits them to their targets and modulates their catalytic activity. This substrate dependent regulation of ATP
Park, G.; Xue, C.; Zhao, X.; Kim, Y.; Orbach, M.; Xu, J. R.
Rice blast fungus ( Magnaporthe grisea) forms a highly specialized infection structure for plant penetration, the appressorium, the formation and growth of which are regulated by the Mst11- Mst7- Pmk1 mitogen- activated protein kinase cascade. We characterized the MST50 gene that directly interacts with both MST11 and MST7. Similar to the mst11 mutant, the mst50 mutant was defective in appressorium formation, sens...
Zhao, D; Yu, Q; Chen, M; Ma, H
The Arabidopsis floral regulatory genes APETALA3 (AP3) and PISTILLATA (PI) are required for the B function according to the ABC model for floral organ identity. AP3 and PI expression are positively regulated by the LEAFY (LFY) and UNUSUAL FLORAL ORGANS (UFO) genes. UFO encodes an F-box protein, and we have shown previously that UFO genetically interacts with the ASK1 gene encoding a SKP1 homologue; both the F-box containing protein and SKP1 are subunits of ubiquitin ligases. We show here that the ask1-1 mutation can enhance the floral phenotypes of weak lfy and ap3 mutants; therefore, like UFO, ASK1 also interacts with LFY and AP3 genetically. Furthermore, our results from RNA in situ hybridizations indicate that ASK1 regulates early AP3 and PI expression. These results support the idea that UFO and ASK1 together positively regulate AP3 and PI expression. We propose that the UFO and ASK1 proteins are components of a ubiquitin ligase that mediates the proteolysis of a repressor of AP3 and PI expression. Our genetic studies also indicate that ASK1 and UFO play a role in regulating the number of floral organ primordia, and we discuss possible mechanisms for such a regulation.
Imilce A Rodriguez-Fernandez
Full Text Available The Adaptor Protein (AP-3 complex is an evolutionary conserved, molecular sorting device that mediates the intracellular trafficking of proteins to lysosomes and related organelles. Genetic defects in AP-3 subunits lead to impaired biogenesis of lysosome-related organelles (LROs such as mammalian melanosomes and insect eye pigment granules. In this work, we have performed a forward screening for genetic modifiers of AP-3 function in the fruit fly, Drosophila melanogaster. Specifically, we have tested collections of large multi-gene deletions--which together covered most of the autosomal chromosomes-to identify chromosomal regions that, when deleted in single copy, enhanced or ameliorated the eye pigmentation phenotype of two independent AP-3 subunit mutants. Fine-mapping led us to define two non-overlapping, relatively small critical regions within fly chromosome 3. The first critical region included the Atg2 gene, which encodes a conserved protein involved in autophagy. Loss of one functional copy of Atg2 ameliorated the pigmentation defects of mutants in AP-3 subunits as well as in two other genes previously implicated in LRO biogenesis, namely Blos1 and lightoid, and even increased the eye pigment content of wild-type flies. The second critical region included the ArfGAP1 gene, which encodes a conserved GTPase-activating protein with specificity towards GTPases of the Arf family. Loss of a single functional copy of the ArfGAP1 gene ameliorated the pigmentation phenotype of AP-3 mutants but did not to modify the eye pigmentation of wild-type flies or mutants in Blos1 or lightoid. Strikingly, loss of the second functional copy of the gene did not modify the phenotype of AP-3 mutants any further but elicited early lethality in males and abnormal eye morphology when combined with mutations in Blos1 and lightoid, respectively. These results provide genetic evidence for new functional links connecting the machinery for biogenesis of LROs with
Víctor Julio Flórez Roncancio
Full Text Available Solidago x luteus (M. L. Greene Broulliet y Semple (= x Solidaster hybridus, x S. luteus es una planta que responde a días cortos (DC para el desarrollo floral. En este proceso se ha establecido la participación de varias fitohormonas, entre éstas, la presencia del ácido abscísico (ABA en zonas y periodos específicos durante el desarrollo de la flor lo cual sugiere su acción promotora en la velocidad de antesis floral de esta especie en DC. En este trabajo se buscaron nuevos indicios de la participación de fitohormonas presentes en la fracción ácida con el proceso de floración. En una primera etapa, extractos foliares provenientes de hojas de plantas en días largos (caracterizadas por menor velocidad de antesis floral se aplicaron en botones florales de plantas en días cortos (caracterizadas por una mayor velocidad de antesis floral. Se realizaron ocho aplicaciones con diferentes frecuencias totalizando un periodo de tratamiento de 25 días. Los resultados mostraron que las sustancias presentes en los extractos de la fracción ácida, no alteran la velocidad promedio de antesis floral en los botones florales de plantas en DC. En la segunda etapa del experimento, la cuantificación de los extractos por ELISA, permitió establecer una mayor concentración de ABA en los extractos de hojas y de botones florales de plantas en DC y de botones florales en el inicio del tratamiento. Estos resultados confirman la relación del ABA con la mayor velocidad de antesis floral en plantas de Solidago x luteus en condiciones de DC.Solidago x luteus (M.L. Greene Broulliet & Semple (= x Solidaster hybridus, x S. luteus is a plant that respond to short days (SD for flower development. In this process, there has been established the involvement of many phytohormones, between these, the presence of the abscisic acid (ABA in zones and specific periods during flower development, suggests its promoter roll on the floral anthesis period of this species under
Kopyl, S A; Dorogova, N V; Akhmamet'eva, E M; Omel'ianchuk, L V; Chang, L -S
The protein Merlin is involved in the regulation of cell proliferation and differentiation in the eyes and wings of Drosophila and is a homolog of the human protein encoded by the Neurofibromatosis 2 (NF2) gene whose mutations cause auricular nerve tumors. Recent studies show that Merlin and Expanded cooperatively regulate the recycling of membrane receptors, such as the epidermal growth factor receptor (EGFR). By performing a search for potential genetic interactions between Merlin (Mer) and the genes important for vesicular trafficking, we found that ectopic expression in the wing pouch of the clathrin adapter protein Lap involved in clathrin-mediated receptor endocytosis resulted in the formation of extra vein materials. On the one hand, coexpression of wild-type Merlin and lap in the wing pouch restored normal venation, while overexpression of a dominant-negative mutant Mer(DBB) together with lap enhanced ectopic vein formation. Using various constructs with Merlin truncated copies, we showed the C-terminal portion of the Merlin protein to be responsible for the Merlin-lap genetic interaction. Furthermore, we showed that the Merlin and Lap proteins colocalized at the cortex of the wing imaginal disc cells.
The structure of receptacular surfaces of floral nectaries at two flowering stages and the structure of the outer surface of the receptacle of Sorbus aucuparia were investigated using scanning electron microscopy...
Tomimatsu, Hiroshi; Ohara, Masashi
... than those of outcrossers. This phenomenon has been explained by sex-allocation theory, which considers allocation of resources to different floral functions, yet its hierarchical structures have mostly been ignored in previous studies...
Clearwater, Michael J; Revell, Maria; Noe, Stevie; Manley-Harris, Merilyn
Floral nectar can be variable in composition, influencing pollinator behaviour and the composition of honey derived from it. The non-peroxide antibacterial activity of mānuka (Leptospermum scoparium, Myrtaceae) honey results from the chemical conversion of the triose sugar dihydroxyacetone (DHA), after DHA accumulates for an unknown reason in the nectar. This study examined variation in nectar DHA, glucose, fructose and sucrose content with floral stage of development, between mānuka genotypes with differing flower morphology, and in response to water stress. Six mānuka genotypes were grown without nectar-feeding insects. Stages of flower development were defined, nectar was harvested and its composition was compared between stages and genotypes, and with floral morphology. Water stress was imposed and its effect on nectar composition was examined. Nectar was present from soon after flower opening until the end of petal abscission, with the quantity of accumulated nectar sugars rising, then stabilizing or falling, indicating nectar secretion followed by reabsorption in some genotypes. The quantity of DHA, the ratio of DHA to other nectar sugars and the fructose to glucose ratio also varied with stage of development, indicating differences in rates of production and reabsorption between nectar components. Nectar composition and yield per flower also differed between genotypes, although neither was positively related to nectary area or stomatal density. Drying soil had no effect on nectar composition or yield, but variation in nectar yield was correlated with temperature prior to nectar sampling. Mānuka nectar yield and composition are strongly influenced by plant genotype, flower age and the environment. There were clear stoichiometric relationships between glucose, fructose and sucrose per flower, but DHA per flower was only weakly correlated with the amount of other sugars, suggesting that accumulation of the triose sugar is indirectly coupled to secretion of
Berbel, A; Navarro, C; Ferrándiz, C; Cañas, L A; Madueño, F; Beltrán, J P
APETALA1 (AP1) and its homologue SQUAMOSA (SQUA) are key regulatory genes specifying floral meristem identity in the model plants Arabidopsis and Antirrhinum. Despite many similarities in their sequence, expression and functions, only AP1 appears to have the additional role of specifying sepal and petal identity. No true AP1/SQUA-functional homologues from any other plant species have been functionally studied in detail, therefore the question of how the different functions of AP1-like genes are conserved between species has not been addressed. We have isolated and characterized PEAM4, the AP1/SQUA-functional homologue from pea, a plant with a different floral morphology and inflorescence architecture to that of Arabidopsis or Antirrhinum. PEAM4 encodes for a polypeptide 76% identical to AP1, but lacks the C-terminal prenylation motif, common to AP1 and SQUA, that has been suggested to control the activity of AP1. Nevertheless, constitutive expression of PEAM4 caused early flowering in tobacco and Arabidopsis. In Arabidopsis, PEAM4 also caused inflorescence-to-flower transformations similar to constitutive AP1 expression, and was able to rescue the floral organ defects of the strong ap1-1 mutant. Our results suggest that the control of both floral meristem and floral organ identity by AP1 is not restricted to Arabidopsis, but is extended to species with diverse floral morphologies, such as pea.
Lawton, Anna P; Prigozy, Theodore I; Brossay, Laurent; Pei, Bo; Khurana, Archana; Martin, Donald; Zhu, Tiancheng; Späte, Kira; Ozga, Megda; Höning, Stefan; Bakke, Oddmund; Kronenberg, Mitchell
The short cytoplasmic tail of mouse CD1d (mCD1d) is required for its endosomal localization, for the presentation of some glycolipid Ags, and for the development of Valpha14i NKT cells. This tail has a four-amino acid Tyr-containing motif, Tyr-Gln-Asp-Ile (YQDI), similar to those sequences known to be important for the interaction with adaptor protein complexes (AP) that mediate the endosomal localization of many different proteins. In fact, mCD1d has been shown previously to interact with the AP-3 adaptor complex. In the present study, we mutated each amino acid in the YQDI motif to determine the importance of the entire motif sequence in influencing mCD1d trafficking, its interaction with adaptors, and its intracellular localization. The results indicate that the Y, D, and I amino acids are significant functionally because mutations at each of these positions altered the intracellular distribution of mCD1d and reduced its ability to present glycosphingolipids to NKT cells. However, the three amino acids are not all acting in the same way because they differ with regard to how they influence the intracellular distribution of CD1d, its rate of internalization, and its ability to interact with the mu subunit of AP-3. Our results emphasize that multiple steps, including interactions with the adaptors AP-2 and AP-3, are required for normal trafficking of mCD1d and that these different steps are mediated by only a few cytoplasmic amino acids.
Dráber, Peter; Štěpánek, Ondřej; Hrdinka, Matouš; Drobek, Aleš; Chmátal, Lukáš; Malá, Linda; Ormsby, Tereza; Angelisová, Pavla; Hořejší, Václav; Brdička, Tomáš
Roč. 287, č. 27 (2012), s. 22812-228221 ISSN 0021-9258 R&D Projects: GA ČR GEMEM/09/E011; GA ČR(CZ) GBP302/12/G101; GA MŠk 1M0506 Institutional research plan: CEZ:AV0Z50520514 Institutional support: RVO:68378050 Keywords : adaptor proteins * myeloid cell * signal transduction * tetraspanins * LST1/A Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.651, year: 2012
Stella M. Solís
Full Text Available Se analizaron los patrones de venación floral en Cardiospermum grandiflorum, Urvillea chacoensis y Thinouia mucronata (Sapindaceae-Paullinieae. Estas especies son monoicas y la inflorescencia es un tirso que posee flores estaminadas y bisexuadas funcionalmente pistiladas. Cardiospermum grandiflorum y U. chacoensis pertenecen a la subtribu Paulliniinae, caracterizada por las flores oblicuamente zigomorfas; mientras T. mucronata pertenece a Thinouiinae, subtribu monotípica con flores actinomorfas. En las especies estudiadas el patrón de venación es similar en ambos tipos de flores, a partir de una sifonostela ectofloica central irradian trazas vasculares que inervan los verticilos periánticos, presentando el fenómeno de progresiva fusión y adnación. El tejido vascular que inerva los nectarios está representado por cordones de floema. En relación a la vascularización floral de estas especies, las diferencias en la venación se observan en las trazas de los complejos sépalo-petalar que irradian de la sifonostela ectofloica central; mientras el patrón de venación de los verticilos fértiles es común a todas ellas. La información obtenida apoya la posición basal de Thinouia en la tribu Paullinieae.The floral venation patterns of Cardiospermum grandiflorum, Urvillea chacoensis and Thinouia mucronata, are surveyed. These species are monoecious and the inflorescence is a thyrse carrying staminate and bisexual flowers funcionally pistillate. Cardiospermum grandiflorum and U. chacoensis belong to the subtribe Paulliniinae which is characterized by obliquely zygomorphic flowers, whereas T. mucronata belongs to the monotypic Thinouiinae which presents actinomorphic flowers. Vascular pattern is similar in both types of flowers of the studied species; from one ectofloic siphonostele depart vascular traces that supply the perianth whorls displaying phenomena of progressive fusion and adnation. Vascular tissue supplying the nectaries is
Zhang, Yaofeng; Zhang, Dongqing; Yu, Huasheng; Lin, Baogang; Fu, Ying; Hua, Shuijin
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
Ghag, Siddhesh B.; Shekhawat, Upendra K. Singh; Ganapathi, Thumballi R.
Antimicrobial peptides are a potent group of defense active molecules that have been utilized in developing resistance against a multitude of plant pathogens. Floral defensins constitute a group of cysteine-rich peptides showing potent growth inhibition of pathogenic filamentous fungi especially Fusarium oxysporum in vitro. Full length genes coding for two Petunia floral defensins, PhDef1 and PhDef2 having unique C- terminal 31 and 27 amino acid long predicted prodomains, were overexpressed i...
Full Text Available AbstractThe flowers of different plant species have diverse scents with varied chemical compositions. Hence, every floral scent does not uniformly affect insect feeding preferences. The blowfly, Phormia regina, is a nectar feeder, and when a fly feeds on flower nectar, its olfactory organs, antennae, and maxillary palps are exposed to the scent. Generally, feeding preference is influenced by food flavor, which relies on both taste and odor. Therefore, the flies perceive the sweet taste of nectar and the particular scent of the flower simultaneously, and this olfactory information affects their feeding preference. Here, we show that the floral scents of 50 plant species have various effects on their sucrose feeding motivation, which was evaluated using the proboscis extension reflex (PER. Those floral scents were first categorized into three groups, based on their effects on the PER threshold sucrose concentration, which indicates whether a fly innately dislikes, ignores, or likes the target scent. Moreover, memory of olfactory experience with those floral scents during sugar feeding influenced the PER threshold. After feeding on sucrose solutions flavored with floral scents for 5 days, the scents did not consistently show the previously observed effects. Considering such empirical effects of scents on the PER threshold, we categorized the effects of the 50 tested floral scents on feeding preference into 16 of all possible 27 theoretical types. We then conducted the same experiments with flies whose antennae or maxillary palps were ablated prior to PER test in a fly group naïve to floral scents and prior to the olfactory experience during sugar feeding in the other fly group in order to test how these organs were involved in the effect of the floral scent. The results suggested that olfactory inputs through these organs play different roles in forming or modifying feeding preferences. Thus, our study contributes to an understanding of underlying
Gralinski, Lisa E; Menachery, Vineet D; Morgan, Andrew P; Totura, Allison L; Beall, Anne; Kocher, Jacob; Plante, Jessica; Harrison-Shostak, D Corinne; Schäfer, Alexandra; Pardo-Manuel de Villena, Fernando; Ferris, Martin T; Baric, Ralph S
Host genetic variation is known to contribute to differential pathogenesis following infection. Mouse models allow direct assessment of host genetic factors responsible for susceptibility to Severe Acute Respiratory Syndrome coronavirus (SARS-CoV). Based on an assessment of early stage lines from the Collaborative Cross mouse multi-parent population, we identified two lines showing highly divergent susceptibilities to SARS-CoV: the resistant CC003/Unc and the susceptible CC053/Unc. We generated 264 F2 mice between these strains, and infected them with SARS-CoV. Weight loss, pulmonary hemorrhage, and viral load were all highly correlated disease phenotypes. We identified a quantitative trait locus of major effect on chromosome 18 (27.1-58.6 Mb) which affected weight loss, viral titer and hemorrhage. Additionally, each of these three phenotypes had distinct quantitative trait loci [Chr 9 (weight loss), Chrs 7 and 12 (virus titer), and Chr 15 (hemorrhage)]. We identified Ticam2, an adaptor protein in the TLR signaling pathways, as a candidate driving differential disease at the Chr 18 locus. Ticam2-/- mice were highly susceptible to SARS-CoV infection, exhibiting increased weight loss and more pulmonary hemorrhage than control mice. These results indicate a critical role for Ticam2 in SARS-CoV disease, and highlight the importance of host genetic variation in disease responses. Copyright © 2017 Gralinski et al.
Li, Youjun; Wei, Zhiyi; Zhang, Junyi; Yang, Zhou; Zhang, Mingjie
The tumor suppressor gene Nf2 product, Merlin, plays vital roles in controlling proper development of organ sizes by specifically binding to a large number of target proteins localized both in cytoplasm and nuclei. The FERM domain of Merlin is chiefly responsible for its binding to target proteins, although the molecular basis governing these interactions are poorly understood due to lack of structural information. Here, we report the crystal structure of the Merlin FERM domain in complex with its binding domain derived from the E3 ubiquitin ligase substrate adaptor DCAF1 (also known as VPRBP). Unlike target binding modes found in ERM proteins, the Merlin-FERM binding domain of DCAF1 folds as a β-hairpin and binds to the α1/β5-groove of the F3 lobe of Merlin-FERM via extensive hydrophobic interactions. In addition to providing the first structural glimpse of a Merlin-FERM·target complex, the structure of the Merlin·DCAF1 complex is likely to be valuable for understanding the interactions of Merlin with its binding partners other than DCAF1. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
Okumura, Mayumi; Ichioka, Fumitaka; Kobayashi, Ryota; Suzuki, Hironori; Yoshida, Haruna; Shibata, Hideki; Maki, Masatoshi
Alix and TSG101, known to physically interact with each other, have Pro-rich regions that are bound by ALG-2 Ca2+-dependently. We investigated the role of ALG-2 in the Alix-TSG101 association by pulldown assays using Strep-tagged Alix and its various mutants. The ALG-2-binding site was required for the Ca2+-dependent pulldown of TSG101 using HEK293T cells, whereas the PSAP sequence, a binding motif for the UEV domain of TSG101, was dispensable. Alix-TSG101 association was not observed using ALG-2-knockdown cells but became detectable by addition of the purified recombinant ALG-2 protein in the assay mixtures. Exogenous expression of mGFP-fused ALG-2 also restored the pulldown capability of Strep-Alix, but an alternatively spliced shorter ALG-2 isoform and a dimerization-defective mutant were incompetent. Based on the X-ray crystal structure model showing the presence of one ligand-binding site in each molecule of an ALG-2 dimer, we propose that Ca2+-loaded ALG-2 bridges Alix and TSG101 as an adaptor protein.
Hollopeter, Gunther; Lange, Jeffrey J; Zhang, Ying; Vu, Thien N; Gu, Mingyu; Ailion, Michael; Lambie, Eric J; Slaughter, Brian D; Unruh, Jay R; Florens, Laurence; Jorgensen, Erik M
The AP2 clathrin adaptor complex links protein cargo to the endocytic machinery but it is unclear how AP2 is activated on the plasma membrane. Here we demonstrate that the membrane-associated proteins FCHo and SGIP1 convert AP2 into an open, active conformation. We screened for Caenorhabditis elegans mutants that phenocopy the loss of AP2 subunits and found that AP2 remains inactive in fcho-1 mutants. A subsequent screen for bypass suppressors of fcho-1 nulls identified 71 compensatory mutations in all four AP2 subunits. Using a protease-sensitivity assay we show that these mutations restore the open conformation in vivo. The domain of FCHo that induces this rearrangement is not the F-BAR domain or the µ-homology domain, but rather is an uncharacterized 90 amino acid motif, found in both FCHo and SGIP proteins, that directly binds AP2. Thus, these proteins stabilize nascent endocytic pits by exposing membrane and cargo binding sites on AP2.
Okazaki, Tomohiko; Higuchi, Maiko; Gotoh, Yukiko
The RIG-I-like receptor (RLR) family of intracellular receptors detects viral nucleic acids and transmits an antiviral signal through the adaptor IPS-1. IPS-1 activation triggers host defense mechanisms, including rapid production of type I interferon (IFN), such as IFN-β, and induction of apoptosis. IPS-1 is mainly localized to mitochondria, and this localization has been proposed to be essential for inducing production of type I IFN and IFN-stimulated genes (ISGs). However, the importance of this mitochondrial localization of IPS-1 in executing apoptosis has remained unclear. Here, using IPS-1 mutants that were directed to specific subcellular locations such as cytoplasm, plasma membrane and mitochondria, we found that IPS-1's localization to mitochondria is important to activate caspase, but not to signal for IFN-β gene induction. We also found that IPS-1 possesses a BH3-like motif, which is commonly found among members of the Bcl-2 family. Mutations within this motif promoted IPS-1-induced caspase activation, suggesting that this domain acts as an intrinsic inhibitor domain of apoptosis induction. These results establish that the mitochondrial location of IPS-1 is essential to its ability to induce apoptosis. © 2013 The Authors Genes to Cells © 2013 by the Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.
Rein-Fischboeck, Lisa; Pohl, Rebekka; Haberl, Elisabeth M; Weiss, Thomas S; Buechler, Christa
The adaptor protein alpha-syntrophin (SNTA) is differentially expressed in varying types of cancer and affects triglyceride levels, inflammatory response and cell proliferation. However, little is known about the expression of SNTA in liver diseases. Non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis, inflammation and eventually fibrosis, and may progress to hepatocellular carcinoma (HCC). Here, SNTA mRNA was analyzed in liver tissues from 71 non-alcoholic fatty liver disease patients and 32 controls to assess associations with disease characteristics. SNTA mRNA expression was reduced in NASH liver and negatively correlated with steatosis, inflammation, fibrosis and NASH scores. In the NASH patients, those with type 2 diabetes had a higher fibrosis score, reduced inflammation and increased hepatic SNTA mRNA levels demonstrating a strong association of SNTA mRNA levels with inflammation. Recently, we have shown diminished expression of the high-density lipoprotein scavenger receptor BI (SR-BI) in the liver of syntrophin-deficient mice. Indeed, hepatic SNTA and SR-BI mRNA were positively correlated. SNTA protein was further determined in tumor and non-tumorous tissues of 21 HCC patients. Protein expression was unchanged in the tumor and not related to staging and grading. Present study identified associations of hepatic SNTA mRNA levels with SR-BI and features of NASH assuming a function of this protein in chronic liver disease and cholesterol metabolism. Copyright © 2017 Elsevier Inc. All rights reserved.
Full Text Available The extracellular matrix (ECM performs essential functions in the differentiation, maintenance and remodeling of tissues during development and regeneration, and it undergoes dynamic changes during remodeling concomitant to alterations in the cell-ECM interactions. Here we discuss recent data addressing the critical role of the widely expressed ECM protein, matrilin-2 (Matn2 in the timely onset of differentiation and regeneration processes in myogenic, neural and other tissues and in tumorigenesis. As a multiadhesion adaptor protein, it interacts with other ECM proteins and integrins. Matn2 promotes neurite outgrowth, Schwann cell migration, neuromuscular junction formation, skeletal muscle and liver regeneration and skin wound healing. Matn2 deposition by myoblasts is crucial for the timely induction of the global switch toward terminal myogenic differentiation during muscle regeneration by affecting transforming growth factor beta/bone morphogenetic protein 7/Smad and other signal transduction pathways. Depending on the type of tissue and the pathomechanism, Matn2 can also promote or suppress tumor growth.
Chen, Y; Grall, D; Salcini, A E
The serine protease thrombin activates G protein signaling systems that lead to Ras activation and, in certain cells, proliferation. Whereas the steps leading to Ras activation by G protein-coupled receptors are not well defined, the mechanisms of Ras activation by receptor tyrosine kinases have ...... kinase activation, gene induction and cell growth. From these data, we conclude that Shc represents a crucial point of convergence between signaling pathways activated by receptor tyrosine kinases and G protein-coupled receptors.......The serine protease thrombin activates G protein signaling systems that lead to Ras activation and, in certain cells, proliferation. Whereas the steps leading to Ras activation by G protein-coupled receptors are not well defined, the mechanisms of Ras activation by receptor tyrosine kinases have...... recently been elucidated biochemically and genetically. The present study was undertaken to determine whether common signaling components are used by these two distinct classes of receptors. Here we report that the adaptor protein Shc, is phosphorylated on tyrosine residues following stimulation...
Suzuki, Jon Y; Amore, Teresita D; Calla, Bernarda; Palmer, Nathan A; Scully, Erin D; Sattler, Scott E; Sarath, Gautam; Lichty, Joanne S; Myers, Roxana Y; Keith, Lisa M; Matsumoto, Tracie K; Geib, Scott M
Anthurium amnicola Dressler possesses a number of desirable and novel ornamental traits such as a purple-colored upright spathe, profuse flowering, and floral scent, some of which have been introgressed into modern Anthurium cultivars. As a first step in identifying genes associated with these traits, the transcriptome from root, leaf, spathe, and spadix from an accession of A. amnicola was assembled, resulting in 28,019 putative transcripts representing 19,458 unigenes. Genes involved in pigmentation, including those for the metabolism of chlorophyll and the biosynthesis of carotenoids, phenylpropanoids, and flavonoids were identified. The expression levels of one MYB transcription factor was highly correlated with naringenin 3-dioxygenase (F3H) and dihydroflavonol-4-reductase (DFR) in leaves, whereas a bHLH transcription factor was highly correlated with flavonoid 3'-monooxygenase (F3'H) and a DFR in spathes, suggesting that these two transcription factors might regulate flavonoid and anthocyanin synthesis in A. amnicola. Gene sequence and expression data from four major organs of A. amnicola provide novel basal information for understanding the genetic bases of ornamental traits and the determinants and evolution of form and function in the Araceae.
Ryu, Jae Yong; Lee, Hyo-Jun; Seo, Pil Joon; Jung, Jae-Hoon; Ahn, Ji Hoon; Park, Chung-Mo
Soil salinity is one of the most serious agricultural problems that significantly reduce crop yields in the arid and semi-arid regions. It influences various phases of plant growth and developmental processes, such as seed germination, leaf and stem growth, and reproductive propagation. Salt stress delays the onset of flowering in many plant species. We have previously reported that the Arabidopsis BROTHER OF FT AND TFL1 (BFT) acts as a floral repressor under salt stress. However, the molecular mechanisms underlying the BFT function in the salt regulation of flowering induction is unknown. In this work, we found that BFT delays flowering under high salinity by competing with FLOWERING LOCUS T (FT) for binding to the FD transcription factor. The flowering time of FD-deficient fd-2 mutant was insensitive to high salinity. BFT interacts with FD in the nucleus via the C-terminal domain of FD, which is also required for the interaction of FD with FT, and interferes with the FT-FD interaction. These observations indicate that BFT constitutes a distinct salt stress signaling pathway that modulates the function of the FT-FD module and possibly provides an adaptation strategy that fine-tunes photoperiodic flowering under high salinity.
Koo, Seong Joo; Markovic, Stefan; Puchkov, Dmytro; Mahrenholz, Carsten C; Beceren-Braun, Figen; Maritzen, Tanja; Dernedde, Jens; Volkmer, Rudolf; Oschkinat, Hartmut; Haucke, Volker
Neurotransmission depends on the exo-endocytosis of synaptic vesicles at active zones. Synaptobrevin 2 [also known as vesicle-associated membrane protein 2 (VAMP2)], the most abundant synaptic vesicle protein and a major soluble NSF attachment protein receptor (SNARE) component, is required for fast calcium-triggered synaptic vesicle fusion. In contrast to the extensive knowledge about the mechanism of SNARE-mediated exocytosis, little is known about the endocytic sorting of synaptobrevin 2. Here we show that synaptobrevin 2 sorting involves determinants within its SNARE motif that are recognized by the ANTH domains of the endocytic adaptors AP180 and clathrin assembly lymphoid myeloid leukemia (CALM). Depletion of CALM or AP180 causes selective surface accumulation of synaptobrevin 2 but not vGLUT1 at the neuronal surface. Endocytic sorting of synaptobrevin 2 is mediated by direct interaction of the ANTH domain of the related endocytic adaptors CALM and AP180 with the N-terminal half of the SNARE motif centered around M46, as evidenced by NMR spectroscopy analysis and site-directed mutagenesis. Our data unravel a unique mechanism of SNARE motif-dependent endocytic sorting and identify the ANTH domain proteins AP180 and CALM as cargo-specific adaptors for synaptobrevin endocytosis. Defective SNARE endocytosis may also underlie the association of CALM and AP180 with neurodevelopmental and cognitive defects or neurodegenerative disorders.
Li, Wenna; Ke, Yuehua; Wang, Yufei; Yang, Mingjuan; Gao, Junguang; Zhan, Shaoxia; Xinying, Du; Huang, Liuyu; Li, Wenfeng; Chen, Zeliang; Li, Juan
Brucella spp. are known to avoid host immune recognition and weaken the immune response to infection. Brucella like accomplish this by employing two clever strategies, called the stealth strategy and hijacking strategy. The TIR domain-containing protein (TcpB/Btp1) of Brucella melitensis is thought to be involved in inhibiting host NF-κB activation by binding to adaptors downstream of Toll-like receptors. However, of the five TIR domain-containing adaptors conserved in mammals, whether MyD88 or MAL, even other three adaptors, are specifically targeted by TcpB has not been identified. Here, we confirmed the effect of TcpB on B.melitensis virulence in mice and found that TcpB selectively targets MAL. By using siRNA against MAL, we found that TcpB from B.melitensis is involved in intracellular survival and that MAL affects intracellular replication of B.melitensis. Our results confirm that TcpB specifically targets MAL/TIRAP to disrupt downstream signaling pathways and promote intra-host survival of Brucella spp. Copyright © 2016 Elsevier Inc. All rights reserved.
Carvajal-Gonzalez, Jose Maria; Gravotta, Diego; Mattera, Rafael; Diaz, Fernando; Perez Bay, Andres; Roman, Angel C.; Schreiner, Ryan P.; Thuenauer, Roland; Bonifacino, Juan S.; Rodriguez-Boulan, Enrique
The coxsackie and adenovirus receptor (CAR) plays key roles in epithelial barrier function at the tight junction, a localization guided in part by a tyrosine-based basolateral sorting signal, 318YNQV321. Sorting motifs of this type are known to route surface receptors into clathrin-mediated endocytosis through interaction with the medium subunit (μ2) of the clathrin adaptor AP-2, but how they guide new and recycling membrane proteins basolaterally is unknown. Here, we show that YNQV functions as a canonical YxxΦ motif, with both Y318 and V321 required for the correct basolateral localization and biosynthetic sorting of CAR, and for interaction with a highly conserved pocket in the medium subunits (μ1A and μ1B) of the clathrin adaptors AP-1A and AP-1B. Knock-down experiments demonstrate that AP-1A plays a role in the biosynthetic sorting of CAR, complementary to the role of AP-1B in basolateral recycling of this receptor. Our study illustrates how two clathrin adaptors direct basolateral trafficking of a plasma membrane protein through interaction with a canonical YxxΦ motif. PMID:22343291
Full Text Available The vast diversity of floral colours in many flowering plant families, paired with the observation of preferences among pollinators, suggests that floral colour may be involved in the process of speciation in flowering plants. While transitions in floral colour have been examined in numerous genera, we have very little information on the consequences of floral colour transitions to the evolutionary success of a clade. Overlaid upon these patterns is the possibility that certain floral colours are more prevalent in certain environments, with the causes of differential diversification being more directly determined by geographical distribution. Here we examine transition rates to anthocyanin + carotenoid rich (red/orange/fuschia flowers and examine whether red/orange flowers are associated with differences in speciation and/or extinction rates in Mimulus. Because it has been suggested that reddish flowers are more prevalent at high elevation, we also examine the macroevolutionary evidence for this association and determine if there is evidence for differential diversification at high elevations. We find that, while red/orange clades have equivalent speciation rates, the trait state of reddish flowers reverts more rapidly to the nonreddish trait state. Moreover, there is evidence for high speciation rates at high elevation and no evidence for transition rates in floral colour to differ depending on elevation.
Salzmann, C C; Cozzolino, S; Schiestl, F P
One third of all orchid species are deceptive and do not reward their pollinators. Such deceptive orchids are often characterised by unusually high variation in floral signals such as colour and scent. In this study, we investigated the scent composition of two Mediterranean food-deceptive orchids Orchis mascula, Orchis pauciflora, and their hybrid, O. x colemanii. Scent was collected IN SITU by headspace sorption and was subsequently analysed with gas chromatography and gas chromatography-mass spectrometry. We compared variation of odour compounds within and between populations as well as species. We identified 35 floral scent compounds, mainly monoterpenes, which were shared by both species. Both quantitative and qualitative variability within and among populations was high. Many individuals within species could be classified to different "odour-types". In spite of high qualitative and quantitative intra- and inter-population variability, the species were clearly differentiated in their scent bouquets, whereas most hybrid individuals emitted an intermediate scent.
Thomson, Diane M
Time series of abundances are critical for understanding how abiotic factors and species interactions affect population dynamics, but are rarely linked with experiments and also scarce for bee pollinators. This gap is important given concerns about declines in some bee species. I monitored honey bee (Apis mellifera) and bumble bee (Bombus spp.) foragers in coastal California from 1999, when feral A. mellifera populations were low due to Varroa destructor, until 2014. Apis mellifera increased substantially, except between 2006 and 2011, coinciding with declines in managed populations. Increases in A. mellifera strongly correlated with declines in Bombus and reduced diet overlap between them, suggesting resource competition consistent with past experimental results. Lower Bombus numbers also correlated with diminished floral resources. Declines in floral abundances were associated with drought and reduced spring rainfall. These results illustrate how competition with an introduced species may interact with climate to drive local decline of native pollinators. © 2016 John Wiley & Sons Ltd/CNRS.
Chen, L; Mehta, A; Berenbaum, M; Zangerl, A R; Engeseth, N J
Honeys from different floral sources were evaluated for their antioxidant content and for their ability to inhibit enzymatic browning in fruits and vegetables. Antioxidant contents of honeys vary widely from different floral sources, as do their abilities to protect against enzymatic browning. Polyphenol oxidase (PPO) activity was reduced over a range of approximately 2-45% in fruit and vegetable homogenates, corresponding to a reduction in browning index by 2.5-12 units. Soy honey was particularly effective when compared to clover honey, which had a similar antioxidant content. When compared to commercial inhibitors of browning, honeys were less effective; however, in combination they added to the effectiveness of metabisulfite and ascorbic acid. Honey has great potential to be used as a natural source of antioxidants to reduce the negative effects of PPO browning in fruit and vegetable processing.
Full Text Available La polinización en Gesneriaceae comúnmente se asocia a síndromes de ornitofilia o melitofilia, siendo usual además la visita a las flores por especies robadoras de néctar. Se presenta una nota sobre la fauna que visita las flores de Seemannia sylvatica en Cusco, registrándose colibríes e insectos visitando las flores. En base a las características florales y conducta de los visitadores florales se sugiere que las flores de S. sylvatica presentan un síndrome ornitofílico. Se concluye que únicamente los colibríes serian los polinizadores, mientras que los insectos visitadores no intervendrían en la polinización y serian robadores del néctar de las flores.
Matias-Guiu, Pau; Rodríguez-Bencomo, Juan José; Orriols, Ignacio; Pérez-Correa, José Ricardo; López, Francisco
The organoleptic quality of wine distillates depends on raw materials and the distillation process. Previous work has shown that rectification columns in batch distillation with fixed reflux rate are useful to obtain distillates or distillate fractions with enhanced organoleptic characteristics. This study explores variable reflux rate operating strategies to increase the levels of terpenic compounds in specific distillate fractions to emphasize its floral aroma. Based on chemical and sensory analyses, two distillate heart sub-fractions obtained with the best operating strategy found, were compared with a distillate obtained in a traditional alembic. Results have shown that a drastic reduction of the reflux rate at an early stage of the heart cut produced a distillate heart sub-fraction with a higher concentration of terpenic compounds and lower levels of negative aroma compounds. Therefore, this sub-fraction presented a much more noticeable floral aroma than the distillate obtained with a traditional alembic. Copyright © 2016 Elsevier Ltd. All rights reserved.
Wright, G. A.; Baker, D. D.; Palmer, M. J.; Stabler, D.; Mustard, J. A.; Power, E. F.; Borland, A. M.; Stevenson, P. C.
Plant defence compounds occur in floral nectar, but their ecological role is not well-understood. We provide the first evidence that plant compounds pharmacologically alter pollinator behaviour by enhancing their memory of reward. Honeybees rewarded with caffeine, which occurs naturally in nectar of Coffea and Citrus species, were three times more likely to remember a learned floral scent than those rewarded with sucrose alone. Caffeine potentiated responses of mushroom body neurons involved in olfactory learning and memory by acting as an adenosine receptor antagonist. Caffeine concentrations in nectar never exceeded the bees’ bitter taste threshold, implying that pollinators impose selection for nectar that is pharmacologically active but not repellent. By using a drug to enhance memories of reward, plants secure pollinator fidelity and improve reproductive success. PMID:23471406
The role of gibberellins (GAs) during floral induction has been widely studied in the annual plant Arabidopsis thaliana. Less is known about this control in perennials. It is thought that GA is a major regulator of flowering in rose. In spring, low GA content may be necessary for floral initiation. GA inhibited flowering in once-flowering roses, whereas GA did not block blooming in continuous-flowering roses. Recently, RoKSN, a homologue of TFL1, was shown to control continuous flowering. The loss of RoKSN function led to continuous flowering behaviour. The objective of this study was to understand the molecular control of flowering by GA and the involvement of RoKSN in this inhibition. In once-flowering rose, the exogenous application of GA3 in spring inhibited floral initiation. Application of GA3 during a short period of 1 month, corresponding to the floral transition, was sufficient to inhibit flowering. At the molecular level, RoKSN transcripts were accumulated after GA3 treatment. In spring, this accumulation is correlated with floral inhibition. Other floral genes such as RoFT, RoSOC1, and RoAP1 were repressed in a RoKSN-dependent pathway, whereas RoLFY and RoFD repression was RoKSN independent. The RoKSN promoter contained GA-responsive cis-elements, whose deletion suppressed the response to GA in a heterologous system. In summer, once-flowering roses did not flower even after exogenous application of a GA synthesis inhibitor that failed to repress RoKSN. A model is presented for the GA inhibition of flowering in spring mediated by the induction of RoKSN. In summer, factors other than GA may control RoKSN. PMID:23175671
Dötterl, Stefan; Glück, Ulrike; Jürgens, Andreas; Woodring, Joseph; Aas, Gregor
In dioecious, zoophilous plants potential pollinators have to be attracted to both sexes and switch between individuals of both sexes for pollination to occur. It often has been suggested that males and females require different numbers of visits for maximum reproductive success because male fertility is more likely limited by access to mates, whereas female fertility is rather limited by resource availability. According to sexual selection theory, males therefore should invest more in pollinator attraction (advertisement, reward) than females. However, our knowledge on the sex specific investment in floral rewards and advertisement, and its effects on pollinator behaviour is limited. Here, we use an approach that includes chemical, spectrophotometric, and behavioural studies i) to elucidate differences in floral nectar reward and advertisement (visual, olfactory cues) in dioecious sallow, Salix caprea, ii) to determine the relative importance of visual and olfactory floral cues in attracting honey bee pollinators, and iii) to test for differential attractiveness of female and male inflorescence cues to honey bees. Nectar amount and sugar concentration are comparable, but sugar composition varies between the sexes. Olfactory sallow cues are more attractive to honey bees than visual cues; however, a combination of both cues elicits the strongest behavioural responses in bees. Male flowers are due to the yellow pollen more colourful and emit a higher amount of scent than females. Honey bees prefer the visual but not the olfactory display of males over those of females. In all, the data of our multifaceted study are consistent with the sexual selection theory and provide novel insights on how the model organism honey bee uses visual and olfactory floral cues for locating host plants. PMID:24676333
Die vorliegende Arbeit befaßt sich mit der Kontrolle des Expressionsmusters des UNUSUAL FLORAL ORGANS (UFO) Gens von Arabidopsis thaliana. UFO wird im Sproß- und Blütenmeristemen aller Entwicklungsstadien der Pflanze exprimiert. In Blütenmeristemen agiert UFO als Kofaktor von LEAFY (LFY) bei der Aktivierung der Organidentitätsgene des zweiten und dritten Wirtels. UFO stellt also einen generellen Faktor der Musterbildung in Meristemen dar. Um regulatorische Gene, die die Expression von UFO bee...
Dötterl, Stefan; Glück, Ulrike; Jürgens, Andreas; Woodring, Joseph; Aas, Gregor
In dioecious, zoophilous plants potential pollinators have to be attracted to both sexes and switch between individuals of both sexes for pollination to occur. It often has been suggested that males and females require different numbers of visits for maximum reproductive success because male fertility is more likely limited by access to mates, whereas female fertility is rather limited by resource availability. According to sexual selection theory, males therefore should invest more in pollinator attraction (advertisement, reward) than females. However, our knowledge on the sex specific investment in floral rewards and advertisement, and its effects on pollinator behaviour is limited. Here, we use an approach that includes chemical, spectrophotometric, and behavioural studies i) to elucidate differences in floral nectar reward and advertisement (visual, olfactory cues) in dioecious sallow, Salix caprea, ii) to determine the relative importance of visual and olfactory floral cues in attracting honey bee pollinators, and iii) to test for differential attractiveness of female and male inflorescence cues to honey bees. Nectar amount and sugar concentration are comparable, but sugar composition varies between the sexes. Olfactory sallow cues are more attractive to honey bees than visual cues; however, a combination of both cues elicits the strongest behavioural responses in bees. Male flowers are due to the yellow pollen more colourful and emit a higher amount of scent than females. Honey bees prefer the visual but not the olfactory display of males over those of females. In all, the data of our multifaceted study are consistent with the sexual selection theory and provide novel insights on how the model organism honey bee uses visual and olfactory floral cues for locating host plants.
Goldbach, R; Kuo, G
The International Symposium on Tospoviruses and Thrips of Floral and Vegetable Crops, held 7–10 November 1995 in Taiwan, attracted scientists active in virology, entomology, and resistance breeding. This blend of expertise provided much new information. The last international meeting on tospoviruses and their interactions with thrips and plants took place 5 years ago in Beltsville, Maryland, USA. During the past 5 years, tospovirus research has greatly expanded, particularly in the area of mo...
Danusha J. Foster; Ralph V. Cartar
Damage to structures that enable mobility can potentially influence foraging behavior. Bumble bees vary in extent of individual wing wear, a trait predicted to affect mechanical performance during foraging. This study asks 1) do bumble bees distribute themselves across different floral densities in accordance with their concurrent wing wear? and 2) does wing use in foraging bumble bees depend on concurrent wing wear? We observed individually identifiable bumble bees foraging in 1-m-super-2 pa...
Pozo, María I.; Herrera, Carlos M.; Bazaga, Pilar
Floral nectar of insect-pollinated plants often contains dense yeast populations, yet little quantitative information exists on patterns and magnitude of species richness of nectar-dwelling yeasts in natural plant commu- nities. This study evaluates yeast species richness at both the plant community and plant species levels in a montane forest area in southern Spain, and also explores possible correlations between the incidence of different yeast species in nectar and their reported tolerance...
Expression of heterosis in floral traits and fruit size in tomato ( Solanum lycopersicum ) hybrids. ... heteroses were found for flower length which ranged from 2.7 to 13.4% and 7.2 to 21.9%, style length 2.6 to 14.5% and 6.8 to 43%, fruit length 1.9 to 5.1% and 4.6 to 27.4% over the better and mid parents, respectively. Similarly ...
Les variations phénologiques sont quelquefois considérées comme une stratégie d'adaptation écologique et physiologique des espèces à leur environnement. La présente étude a eu pour objectif de déterminer les phénophases florales et la production en fruits de Syzygium guineense subsp. macrocarpum sur un ...
Pfluger, J; Zambryski, P
Genetic and physiological analyses implicate auxin flux in patterning, initiation and growth of floral organs. Within the Arabidopsis flower, the ETTIN/ARF3 transcription factor responds to auxin to effect perianth organ number and reproductive organ differentiation. This work describes a modifier of ettin that causes filamentous, mispositioned outer whorl organs and reduced numbers of malformed stamens in the double mutant. The modifier was discovered to be a new allele of the seuss (seu) mu...
Reig, Carmina; Gil-Muñoz, Francisco; Vera-Sirera, Francisco; García-Lorca, Ana; Martínez-Fuentes, Amparo; Mesejo, Carlos; Pérez-Amador, Miguel A; Agustí, Manuel
EjFT1 and EjFT2 genes were isolated and sequenced from leaves of loquat. EjFT1 is involved in bud sprouting and leaf development, and EjFT2 in floral bud induction. Loquat [Eriobotrya japonica (Thunb.) Lindl.] is an evergreen species belonging to the family Rosaceae, such as apple and pear, whose reproductive development, in contrast with these species, is a continuous process that is not interrupted by winter dormancy. Thus, the study of the mechanism of flowering in loquat has the potential to uncover the environmental and genetic networks that trigger flowering more accurately, contributing for a better understanding of the Rosaceae floral process. As a first step toward understanding the molecular mechanisms controlling flowering, extensive defoliation and defruiting assays, together with molecular studies of the key FLOWERING LOCUS T (FT) gene, were carried out. FT exhibited two peaks of expression in leaves, the first one in early to mid-May, the second one in mid-June. Two FT genes, EjFT1 and EjFT2, were isolated and sequenced and studied their expression. Expression of EjFT1 and EjFT2 peaks in mid-May, at bud sprouting. EjFT2 expression peaks again in mid-June, coinciding with the floral bud inductive period. Thus, when all leaves of the tree were continuously removed from early to late May vegetative apex differentiated into panicle, but when defoliation was performed from early to late June apex did not differentiate. On the other hand, fruit removal advanced EjFT1 expression in old leaves and the sooner the fruit detached, the sooner the bud sprouted. Accordingly, results strongly suggest that EjFT1 might be related to bud sprouting and leaf development, while EjFT2 might be involved in floral bud induction. An integrative model for FT functions in loquat is discussed.
Full Text Available In dioecious, zoophilous plants potential pollinators have to be attracted to both sexes and switch between individuals of both sexes for pollination to occur. It often has been suggested that males and females require different numbers of visits for maximum reproductive success because male fertility is more likely limited by access to mates, whereas female fertility is rather limited by resource availability. According to sexual selection theory, males therefore should invest more in pollinator attraction (advertisement, reward than females. However, our knowledge on the sex specific investment in floral rewards and advertisement, and its effects on pollinator behaviour is limited. Here, we use an approach that includes chemical, spectrophotometric, and behavioural studies i to elucidate differences in floral nectar reward and advertisement (visual, olfactory cues in dioecious sallow, Salix caprea, ii to determine the relative importance of visual and olfactory floral cues in attracting honey bee pollinators, and iii to test for differential attractiveness of female and male inflorescence cues to honey bees. Nectar amount and sugar concentration are comparable, but sugar composition varies between the sexes. Olfactory sallow cues are more attractive to honey bees than visual cues; however, a combination of both cues elicits the strongest behavioural responses in bees. Male flowers are due to the yellow pollen more colourful and emit a higher amount of scent than females. Honey bees prefer the visual but not the olfactory display of males over those of females. In all, the data of our multifaceted study are consistent with the sexual selection theory and provide novel insights on how the model organism honey bee uses visual and olfactory floral cues for locating host plants.
Płachno, Bartosz J; Stpiczyńska, Małgorzata; Świątek, Piotr; Davies, Kevin L
Flowers of sexually deceptive taxa generally possess a set of morphological and physiological characters that mimic their insect pollinators. These characters often include a specific insect-like floral configuration, together with scent glands (osmophores) that produce fragrances which chemically resemble insect sex pheromones. Furthermore, these flowers tend not to produce pollinator food rewards. According to some authors, flowers of the Australian bladderwort Utricularia dunlopii (and species of the Utricularia capilliflora complex) resemble insects, and pollination perhaps occurs by pseudocopulation. The aims of this paper are to compare the structure and distribution of floral glandular trichomes in the Australian carnivorous plant U. dunlopii with those of closely related species assigned to the same section and to discuss their putative function. Floral tissues of U. dunlopii P. Taylor, Utricularia paulinae Lowrie, Utricularia dichotoma Labill. and Utricularia uniflora R.Br. (section Pleiochasia) were investigated using light microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry. In U. dunlopii, two long, erect, filiform appendages arising from the upper lip of the corolla, together with three arising from the lower lip, bear numerous glandular trichomes that may function as osmophores. In other species, such as U. uniflora and U. paulinae, glandular papillae on the corolla palate may also function as osmophores. The floral anatomical and morphological organisation of U. dunlopii differs from that of the other investigated species, indicating that its insect pollinators are also likely to differ. Morphological and ultrastructural observations, while generally contributing to our understanding of the flower of U. dunlopii, do not refute the possibility that pollination here may occur by pseudocopulation. Further field-based investigations, however, are now necessary to test this hypothesis.
Rosilda Mara Mussury; Wedson Desidério Fernandes
Studies of the floral biology of canola were accomplished with the objective of enlarging the system and reproductive strategies knowledge of its CTC-4 cultivar in Dourados, Centerwest, Brazil. Brassica napus is self pollinated, presenting however, many resources for the allogamy accomplishment, e.g., abundant pollen, nectar and scent production. The smaller anther were responsible for the production of fruit with smaller and less growth seeds, when compared to the autogamy, autopollination a...
Rodrigues, LC; M. Rodrigues
Hummingbird communities tend to respond to variation in resources, having a positive relationship between abundance and diversity of food resources and the abundance and/or diversity of hummingbirds. Here we examined the influence of floral resource availability, as well as seasonality and type of habitat on the composition of hummingbird species. The study was carried out in two habitats of eastern Brazilian mountaintops. A gradient representative of the structure of hummingbird community, b...