909 resultados para sense organ
Resumo:
Homologous sense suppression of a gene encoding lignin pathway caffeic acid O-methyltransferase (CAOMT) in the xylem of quaking aspen (Populus tremuloides Michx.) resulted in transgenic plants exhibiting novel phenotypes with either mottled or complete red-brown coloration in their woody stems. These phenotypes appeared in all independent transgenic lines regenerated with a sense CAOMT construct but were absent from all plants produced with antisense CAOMT. The CAOMT sense transgene expression was undetectable, and the endogenous CAOMT transcript levels and enzyme activity were reduced in the xylem of some transgenic lines. In contrast, the sense transgene conferred overexpression of CAOMT and significant CAOMT activity in all of the transgenic plants' leaves and sclerenchyma, where normally the expression of the endogenous CAOMT gene is negligible. Thus, our results support the notion that the occurrence of sense cosuppression depends on the degree of sequence homology and endogene expression. Furthermore, the suppression of CAOMT in the xylem resulted in the incorporation of a higher amount of coniferyl aldehyde residues into the lignin in the wood of the sense plants. Characterization of the lignins isolated from these transgenic plants revealed that a high amount of coniferyl aldehyde is the origin of the red-brown coloration—a phenotype correlated with CAOMT-deficient maize (Zea mays L.) brown-midrib mutants.
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Homeobox genes encode a large family of homeodomain proteins that play a key role in the pattern formation of animal embryos. By analogy, homeobox genes in plants are thought to mediate important processes in their embryogenesis, but there is very little evidence to support this notion. Here we described the temporal and spatial expression patterns of a rice homeobox gene, OSH1, during rice embryogenesis. In situ hybridization analysis revealed that in the wild-type embryo, OSH1 was first expressed at the globular stage, much earlier than organogenesis started, in a ventral region where shoot apical meristem and epiblast would later develop. This localized expression of OSH1 indicates that the cellular differentiation has already occurred at this stage. At later stages after organogenesis had initiated, OSH1 expression was observed in shoot apical meristem [except in the L1 (tunica) layer], epiblast, radicle, and their intervening tissues in descending strength of expression level with embryonic maturation. We also performed in situ hybridization analysis with a rice organless embryo mutant, orl1, that develops no embryonic organs. In the orl1 embryo, the expression pattern of OSH1 was the same as that in the wild-type embryo in spite of the lack of embryonic organs. This shows that OSH1 is not directly associated with organ differentiation, but may be related to a regulatory process before or independent of the organ determination. The results described here strongly suggest that, like animal homeobox genes, OSH1 plays an important role in regionalization of cell identity during early embryogenesis.
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Transmitting tissue-specific (TTS) protein is a pollen tube growth-promoting and attracting glycoprotein located in the stylar transmitting tissue extracellular matrix of the pistil of tobacco. The TTS protein backbones have a deduced molecular mass of about 28 kDa, whereas the glycosylated stylar TTS proteins have apparent molecular masses ranging between 50 and 100 kDa. TTS mRNAs and proteins are ectopically produced in transgenic tobacco plants that express either a cauliflower mosaic virus (CaMV) 35S promoter-TTS2 transgene or a CaMV 35S-promoter-NAG1 (NAG1 = Nicotiana tabacum Agamous gene) transgene. However, the patterns of TTS mRNA and protein accumulation and the quality of the TTS proteins produced are different in these two types of transgenic plants. In 35S-TTS transgenic plants, TTS mRNAs and proteins accumulate constitutively in vegetative and floral tissues. However, the ectopically expressed TTS proteins in these transgenic plants accumulate as underglycosylated protein species with apparent molecular masses between 30 and 50 kDa. This indicates that the capacity to produce highly glycosylated TTS proteins is restricted to the stylar transmitting tissue. In 35S-NAG transgenic plants, NAG1 mRNAs accumulate constitutively in vegetative and floral tissues, and TTS mRNAs are induced in the sepals of these plants. Moreover, highly glycosylated TTS proteins in the 50- to 100-kDa molecular mass range accumulate in the sepals of these transgenic, 35S-NAG plants. These results show that the tobacco NAGI gene, together with other yet unidentified regulatory factors, control the expression of TTS genes and the cellular capacity to glycosylate TTS proteins, which are normally expressed very late in the pistil developmental pathway and function in the final stage of floral development. The sepals in the transgenic 35S-NAG plants also support efficient pollen germination and tube growth, similar to what normally occurs in the pistil, and this ability correlates with the accumulation of the highest levels of the 50- to 100-kDa glycosylated TTS proteins.
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The Arabidopsis MADS domain proteins AP1, AP3, PI, and AG specify floral organ identity. All of these proteins contain a MADS domain required for DNA binding and dimerization; a region termed L (linker between MADS domain and K domain), which plays an important role in dimerization specificity; the K domain, named for its similarity to the coiled-coil domain of keratin; and a C-terminal region of unknown function. To determine which regions of these proteins are responsible for their abilities to specify different organs, we have made a number of chimeric MADS box genes. The in vivo function of these chimeric genes was investigated by ectopic expression in transgenic Arabidopsis plants. The four proteins fall into two classes on the basis of regions responsible for their functional specificities. The L region and K domain define the functional specificities of AP3 and PI, while the MADS domain and L region define the functional specificities of AP1 and AG.
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Although the incidence of Gram-positive sepsis has risen strongly, it is unclear how Gram-positive organisms (without endotoxin) initiate septic shock. We investigated whether two cell wall components from Staphylococcus aureus, peptidoglycan (PepG) and lipoteichoic acid (LTA), can induce the inflammatory response and multiple organ dysfunction syndrome (MODS) associated with septic shock caused by Gram-positive organisms. In cultured macrophages, LTA (10 micrograms/ml), but not PepG (100 micrograms/ml), induces the release of nitric oxide measured as nitrite. PepG, however, caused a 4-fold increase in the production of nitrite elicited by LTA. Furthermore, PepG antibodies inhibited the release of nitrite elicited by killed S. aureus. Administration of both PepG (10 mg/kg; i.v.) and LTA (3 mg/kg; i.v.) in anesthetized rats resulted in the release of tumor necrosis factor alpha and interferon gamma and MODS, as indicated by a decrease in arterial oxygen pressure (lung) and an increase in plasma concentrations of bilirubin and alanine aminotransferase (liver), creatinine and urea (kidney), lipase (pancreas), and creatine kinase (heart or skeletal muscle). There was also the expression of inducible nitric oxide synthase in these organs, circulatory failure, and 50% mortality. These effects were not observed after administration of PepG or LTA alone. Even a high dose of LTA (10 mg/kg) causes only circulatory failure but no MODS. Thus, our results demonstrate that the two bacterial wall components, PepG and LTA, work together to cause systemic inflammation and multiple systems failure associated with Gram-positive organisms.
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Here we show that the mature cochlear neurons are a rich source of acidic fibroblast growth factor (aFGF), which is expressed in the neuronal circuitry consisting of afferent and efferent innervation. The site of action of neuronal aFGF is likely to reside in the organ of Corti, where one of the four known FGF receptor (FGFR) tyrosine kinases--namely, FGFR-3 mRNA--is expressed. Following acoustic overstimulation, known to cause damage to the organ of Corti, a rapid up-regulation of FGFR-3 is evident in this sensory epithelium, at both mRNA and protein levels. The present results provide in vivo evidence for aFGF being a sensory neuron-derived, anterogradely transported factor that may exert trophic effects on a peripheral target tissue. In this sensory system, aFGF, rather than being a neurotrophic factor, seems to promote maintenance of the integrity of the organ of Corti. In addition, aFGF, released from the traumatized nerve endings, may be one of the first signals initiating protective recovery and repair processes following damaging auditory stimuli.
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Peer reviewed
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The term coparenting implies a bioparental dyad that often excludes the stepparent's role in sharing parenting across joint-custody households. Focusing solely on this dyad also precludes gaining an understanding of how stepfamily couples manage together the communication and sharing of parental responsibilities with the parent(s) in the shared children's other home. In a departure from this bioparental dyad-focused approach, this study locates the stepfamily couple at the center of an inquiry into managing coparenting across households. This mixed methods design study included in-depth interviews of 32 stepfamily couples whose narratives about coparenting were analyzed using grounded theory methods. Forty-one percent of stepparents engage in direct coparenting communication, sometimes manifested as the coactive approach identified in this study. Stepfamily couples also involve the stepparent indirectly in coparenting communication, through the conferred and consultative approaches. As well, the couples' narratives about coparenting identify them as either united, where they share the experience, or divided, where coparenting is reserved exclusively for the bioparent to manage. The stepfamily couples' narratives about significant coparenting experiences revealed that they experience and make sense of coparenting as 1) struggling, 2) coping, or 3) thriving. No significant relationship was found between marital satisfaction and experiencing coparenting as strugglers, copers or thrivers. Grounded theory analysis of these narratives also reflects the four dichotomous dimensions of 1) regard-disregard, 2) decency-duplicity, 3) facilitation-interference, and 4) accommodation-inflexibility. Significant incidents located along these dimensions contribute to the stepfamily couples' identification as struggling, coping, or thriving in coparenting. Experiences on the extreme ends of the dichotomous dimensions generate positive and negative turning points for the coparenting interactions and relationships. As well, experiences on the negative end of the dimensional poles can present challenges for the stepfamily couples. Finally, a synthesis of the findings related to the dichotomous dimensions generates a theory of shared parenting values expectancy.
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Constructive body theology provides an ethical commitment to and a set of analytical principles for understanding bodily experience. If we insist upon the theological value of embodied experience, how can we give an adequate account of it? Are feminist appeals to the senses useful in developing theological truth claims based in embodied experiences? Feminist theologies which explicitly seek to overcome body/mind dualisms often reinscribe them when they neglect to attend to perception as a critical element of bodily experience. Phenomenological analyses of perception (such as suggested by Merleau-Ponty) strengthen and refine our conception of embodiment. Grounding constructive theology in experience requires understanding experience as bodily perceptual orientation, as perceptual bodily and cultural acts involved in socially and historically situated contextual meaning-making processes. This shift expands phenomenological concepts such as intentionality and habit, and allows for a comparative investigation of historical and cultural differences in embodied experiences through examples found in sensory anthropology. Body theology, framed as principles, strengthens theological projects (such as those by Carter Heyward and Marcella Althaus-Reid, as well as new constructive possibilities) through opening dialogical avenues of exploration into embodied being in the world. Body theology principles help us conceive of and address how our bodily experiencing--our feeling, tasting, hearing, imaging, remembering and other sensory knowledge --comes to matter in our lives, especially where oppressive forces viscerally affect embodied life.
Parent Loss in Adolescence and its Impact on Sense of Self: When an Adolescent Boy Loses His Mother.
Resumo:
Adolescence is a developmental phase that involves physical, emotional, and cognitive changes. Often this period is one of transition that requires significant adjustment both with the individual and the family. It is considered to start with puberty, sometime between the ages of 10 and 13, and end with the transition into adulthood (Kruse & Walper, 2008). Puberty is a term that is used to describe the physical changes that generally occur during adolescence. It is an aspect of the changes that occur during the overarching phase of development. Within adolescence, individuals are confronted with many developmental tasks such as establishing an individual identity, making decisions about the future, and moving from dependence on families to independence (Austrian, 2008).There are many changes that occur during adolescence, including sexual maturation and functioning, endocrine developments, and skeletal and muscular changes. Boys will see a growth of body, pubic, and facial hair, their voice will deepen, and they will begin having erections and wet dreams (Kruse & Walper, 2008). The accelerated transformation of this phase generally has an emotional impact and individuals may feel concerned or self-conscious about their appearance. Ausubel, Montemayor, and Svajian (1977) suggest that adolescents may be more sensitive during this period of development. This sensitivity may be in part due to the rapid growth resulting in a sense of awkwardness in appearance and physical coordination.
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The literature on Iranians who immigrated to countries with modern cultures is sparse. This paper presents a theoretical understanding of the research with a particular appreciation on issues related to gender roles, sexuality, and acculturation within this population. In addition, treatment suggestions with this Iranian immigrant population will be presented through the lens of self psychology and a new perspective about the effects on the sense of self of young immigrant Iranian females will be discussed.
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En este trabajo se presenta un método para la detección de subjetividad a nivel de oraciones basado en la desambiguación subjetiva del sentido de las palabras. Para ello se extiende un método de desambiguación semántica basado en agrupamiento de sentidos para determinar cuándo las palabras dentro de la oración están siendo utilizadas de forma subjetiva u objetiva. En nuestra propuesta se utilizan recursos semánticos anotados con valores de polaridad y emociones para determinar cuándo un sentido de una palabra puede ser considerado subjetivo u objetivo. Se presenta un estudio experimental sobre la detección de subjetividad en oraciones, en el cual se consideran las colecciones del corpus MPQA y Movie Review Dataset, así como los recursos semánticos SentiWordNet, Micro-WNOp y WordNet-Affect. Los resultados obtenidos muestran que nuestra propuesta contribuye de manera significativa en la detección de subjetividad.
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La proximitat del centenari del naixement del poeta alcoià Joan Valls Jordà (1917-1989) convida a la presentació d’un avançament dels treballs sobre inèdits i semiinèdits que han de ser part irrenunciable si volem acostar-nos a la figura i l’obra de Valls amb tota la seua magnitud. El nombre de materials de Valls que no han estat publicats mai o, en cas contrari, els escrits dispersos en la premsa i les plataformes locals diverses, als quals s’ha d’afegir les publicacions d’autor o les edicions privades, reduïdes o limitades, és un corpus que cal revisar. Aquest paper presenta un primer inventari comentat de textos esparsos que tenen una relació directa amb la música i els músics, un recull heterogeni que té voluntat de continuïtat en treballs futurs.
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jahrg. 22, bd. 86 (1901)