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Lipid peroxidation vs. antioxidant modulation in the bivalve Scrobicularia plana in response to environmental mercury-Organ specificities and age effect

Ahmad, I.; Mohmood, I.; Mieiro, C. L.; Coelho, J. P.; Pacheco, M.; Santos, M. A.; Duarte, A. C.; Pereira, E.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.33%
This study aimed at the assessment of mercury burden and its association to damage vs. antioxidant protection in the bivalve Scrobicularia plana environmentally exposed to mercury. Inter-age and organ-specific approaches were applied by using different annual size classes (2+, 3+, 4+ and 5+ year old) and assessing specific organs (gills, digestive gland), respectively. Bivalves were collected from moderately and highly contaminated sites at Laranjo basin – Ria de Aveiro (Portugal), where a mercury gradient was identified, and compared with those from a reference site. Besides total and organic mercury accumulation, endpoints combining lipid peroxidation (LPO), as a damage sign, and antioxidant protection (catalase, CAT; glutathione peroxidase, GPX; glutathione S-transferase, GST, activities) were determined. The whole-body accumulation as total mercury changed according to the environmental gradient for all age classes, while in terms of organic mercury, only 5+-year-old animals showed increased accumulation with increased environmental mercury level. Mercury induced peroxidative damage, showing that antioxidative mechanisms were insufficient. The adaptive capacity to pro-oxidant challenge, expressed as antioxidant induction and lesser vulnerability to enzyme inhibition...

The relevance of temporal and organ specific factors on metals accumulation and biochemical effects in feral fish (Liza aurata) under a moderate contamination scenario

Pereira, P.; Pablo, H. de; Pacheco, M.; Vale, C.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.33%
Moderate contamination scenarios are nowadays challenging ecotoxicologists. An investigative biomonitoring study was performed under those environmental conditions (O ́ bidos lagoon, Portugal) focused on oxidative stress and accumulated metals in Liza aurata liver and kidney, also examining winter–summer variations and organ-specificities. Three sites were surveyed: Barrosa; Bom-Sucesso; Middle lagoon. The higher metal availability at Barrosa (in water and sediment) was reflected in both organ burdens, though liver was more responsive. Oxidative stress (both organs) pointed to a pro- oxidant challenge at Barrosa (both seasons), reinforced by a general stress index. In winter, oxidative stress at Barrosa was related with accumulated metals in both organs, while in summer this cause– effect relationship was only established for kidney since changes in liver were linked with non- contaminant related variables. Winter–summer variations were outstanding in liver and kidney oxidative stress endpoints, pointing to the relevance of considering distinct seasons and organs in the assessment of moderately contaminated systems.

Mapping the protein regions responsible for the functional specificities of the Arabidopsis MADS domain organ-identity proteins.

Krizek, B A; Meyerowitz, E M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 30/04/1996 EN
Relevância na Pesquisa
26.36%
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.

A new family of zinc finger proteins in petunia: structure, DNA sequence recognition, and floral organ-specific expression.

Takatsuji, H; Nakamura, N; Katsumoto, Y
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1994 EN
Relevância na Pesquisa
25.88%
We have previously cloned a gene for a zinc finger protein (EPF1) that is expressed specifically in petals and interacts with the promoter region of the 5-enolpyruvylshikimate-3-phosphate synthase gene in petunia. In an attempt to isolate genes encoding additional factors that interact with this promoter, we cloned four novel genes encoding zinc finger proteins (EPF2-5a, EPF2-5b, EPF2-4, and EPF2-7). Sequence analyses revealed that overall similarity between the EPF1 and the EPF2 protein family, except in the zinc finger motifs and the basic amino acid cluster, was very low, suggesting that the two groups belong to different subfamilies. DNA binding specificities of EPF1, EPF2-5, and EPF2-4 were very similar, as expected from the conserved zinc finger motifs. However, EPF2-7 showed no binding to the probes tested in spite of having the conserved motifs. DNA binding studies using a series of spacing mutant probes suggested a binding mechanism in which the EPF proteins recognize spacings in target DNA. RNA gel blot analyses and histochemical analyses with a promoter and beta-glucuronidase fusion revealed that expression of the EPF2-5 gene (EPF2-5) was petal and stamen specific. Expression of the EPF2-7 gene (EPF2-7) was sepal and petal specific and localized in vascular tissues. The preferential expression in two adjacent floral organs raises the possibility that these genes are downstream transcription factors of floral homeotic genes.

Specificities of olfactory receptor neuron responses to amino acids in the black bullhead catfish (Ameiurus melas)

Dolensek, Jurij; Valentincic, Tine
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.21%
In vivo investigations of catfish olfactory receptor neurons (ORNs) were previously limited to studying responses of spontaneously active cells. The olfactory organ, however, also contains ORNs that lack spontaneous activity and respond to amino acids. To record electrical activity of ORNs that were inactive prior to stimulation, we bathed the olfactory organ with low conductive, highly purified water that reduces shunting and enables detection of action potentials from ORNs distant to the electrode. After stimulation with amino acids, these ORNs elicited either phasic–tonic or tonic only activities. The spike frequency of the phasic activity consisted of transient frequencies up to 108 Hz that lasted <450 ms. All tonic activities saturated at action potential frequencies of 17–21 Hz. Their durations were dose dependent over several log units of concentration as they closely followed that of the suprathreshold amino acid stimulation. Specificities of 44 ORNs were investigated with ten different amino acids tested at 10−4 M. Thirteen ORNs were excited by only one amino acid, l-norvaline, and 22 additional ORNs were excited by l-norvaline and l-methionine. Nine ORNs were excited by >2 amino acids that included l-norvaline. In 29 of 31 neurons responding to >1 amino acid...

Association of HLA Polymorphisms with Post-Transplant Lymphoproliferative Disorder in Solid-Organ Transplant Recipients

Reshef, R; Luskin, MR; Kamoun, M; Vardhanabhuti, S; Tomaszewski, JE; Stadtmauer, EA; Porter, DL; Heitjan, DF; Tsai, DE
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.02%
The association between HLA polymorphisms and PTLD was investigated in a case-control study, comparing 110 predominantly adult solid-organ transplant recipients who developed PTLD to 5601 who did not. Donor and recipient HLA were analyzed. We detected a significant association between recipient HLA-A26 and the development of PTLD (OR 2.74; P=0.0007). In Caucasian recipients, both recipient and donor HLA-A26 were independently associated with development of PTLD (recipient A26 OR 2.99; P=0.0004, donor A26 OR 2.81; P=0.002). Analysis of HLA-A and -B haplotypes revealed that recipient HLA-A26, B38 haplotype was strongly correlated with a higher incidence of EBV-positive PTLD (OR 3.99; p=0.001). The common ancestral haplotype HLA-A1, B8, DR3, when carried by the donor, was protective against PTLD (OR 0.41; p=0.05). Several other HLA specificities demonstrated associations with clinical and pathological characteristics as well as survival. These findings demonstrate the importance of HLA polymorphisms in modulating the risk for PTLD, and may be useful in risk stratification and development of monitoring and prophylaxis strategies.

Requirement for diverse TCR specificities determines regulatory T cell activity in a mouse model of autoimmune arthritis1

Oh, Soyoung; Aitken, Malinda; Simons, Donald M.; Basehoar, Alissa; Garcia, Victoria; Kropf, Elizabeth; Caton, Andrew J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.06%
CD4+CD25+Foxp3+ regulatory T cells (Tregs) are required to restrain the immune system from mounting an autoaggressive systemic inflammatory response, but why their activity can prevent (or allow) organ-specific autoimmunity remains poorly understood. We have examined how TCR specificity contributes to Treg activity using a mouse model of spontaneous autoimmune arthritis, in which CD4+ T cells expressing a clonotypic TCR induce disease by an IL-17-dependent mechanism. Administration of polyclonal Tregs suppressed Th17 cell formation and prevented arthritis development; notably, Tregs expressing the clonotypic TCR did not. These clonotypic Tregs exerted antigen-specific suppression of effector CD4+ T cells using the clonotypic TCR in vivo, but failed to mediate bystander suppression and did not prevent Th17 cells using nonclonotypic TCRs from accumulating in joint-draining lymph nodes of arthritic mice. These studies indicate that the availability of Tregs with diverse TCR specificities can be crucial to their activity in autoimmune arthritis.

Tolerance induction after organ transplantation, “delayed tolerance,” via the mixed chimerism approach: Planting flowers in a battle field

Yamada, Yohei; Benichou, Gilles; Cosimi, A. Benedict; Kawai, Tatsuo
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
Publicado em 01/01/2012 EN
Relevância na Pesquisa
26.1%
We have previously reported that peri-transplant conditioning leads to successful induction of renal allograft tolerance via the mixed chimerism approach in nonhuman primates (NHP) and humans. However, this strategy requires treatments beginning six days prior to transplantation, which limits its relevance only to living donor transplant recipients. To extend the clinical applicability of this approach, we developed a novel regimen “delayed tolerance,” with which the recipient initially undergoes organ transplantation with conventional immunosuppression, followed by conditioning and donor bone marrow transplantation (DBMT) at a later date. This approach might be likened to “planting flowers in a battle field.” That is, the recipient’s immunologic environment after organ transplantation is like a battlefield filled with hostile innate and adaptive immune-responses directed against donor antigeneic specificities. Implanting fragile donor hematopoietic progenitors into this environment and encouraging them to bloom in this vicious field requires special treatments.

The Biology of Autoimmune Response in the Scurfy Mice that Lack the CD4+Foxp3+ Regulatory T-Cells

Ju, Shyr-Te; Sharma, Rahul; Gaskin, Felicia; Kung, John T.; Fu, Shu Man
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 04/04/2012 EN
Relevância na Pesquisa
26.1%
Due to a mutation in the Foxp3 transcription factor, Scurfy mice lack regulatory T-cells that maintain self-tolerance of the immune system. They develop multi-organ inflammation (MOI) and die around four weeks old. The affected organs are skin, tail, lungs and liver. In humans, endocrine and gastrointestinal inflammation are also observed, hence the disease is termed IPEX (Immunodysregulation, Polyendocrinopathy, Enteropathy, X-linked) syndrome. The three week period of fatal MOI offers a useful autoimmune model in which the controls by genetics, T-cell subsets, cytokines, and effector mechanisms could be efficiently investigated. In this report, we will review published work, summarize our recent studies of Scurfy double mutants lacking specific autoimmune-related genes, discuss the cellular and cytokine controls by these genes on MOI, the organ-specificities of the MOI controlled by environments, and the effector mechanisms regulated by specific Th cytokines, including several newly identified control mechanisms for organ-specific autoimmune response.

Organ-Specific and Memory Treg Cells: Specificity, Development, Function, and Maintenance

Gratz, Iris K.; Campbell, Daniel J.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 15/07/2014 EN
Relevância na Pesquisa
26.21%
Foxp3+ regulatory T cells (Treg cells) are essential for establishing and maintaining self-tolerance, and also inhibit immune responses to innocuous environmental antigens. Imbalances and dysfunction in Treg cells lead to a variety of immune-mediated diseases, as deficits in Treg cell function contribute to the development autoimmune disease and pathological tissue damage, whereas overabundance of Treg cells can promote chronic infection and tumorigenesis. Recent studies have highlighted the fact that Treg cells themselves are a diverse collection of phenotypically and functionally specialized populations, with distinct developmental origins, antigen-specificities, tissue-tropisms, and homeostatic requirements. The signals directing the differentiation of these populations, their specificities and the mechanisms by which they combine to promote organ-specific and systemic tolerance, and how they embody the emerging property of regulatory memory are the focus of this review.

Engineering stem cells into organs: Topobiological transformations demonstrated by beak, feather and other ectodermal organ morphogenesis

Chuong, Cheng-Ming; Wu, Ping; Plikus, Maksim; Jiang, Ting-Xin; Widelitz, Randall Bruce
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //2006 EN
Relevância na Pesquisa
26.02%
To accomplish regenerative medicine, several critical issues in stem cell biology have to be solved, including the identification of sources, expanding populations, building them into organs, and assimilating them to the host. While many stem cells can now differentiate along certain lineages, knowledge on how to use them to build organs lags behind. Here we focus on topobiological events that bridge this gap, i.e., the regulation of number, size, axis, shape, arrangement, and architecture during organogenesis. Rather than reviewing detailed molecular pathways known to disrupt organogenesis when perturbed, we highlight conceptual questions at the topobiological level, and ask how cellular and molecular mechanisms can work to explain these phenomena. The avian integument is used as the Rosetta stone because the molecular activities are linked to organ forms which are visually apparent and have functional consequences during evolution as shown by the fossil record and extant diversity. For example, we show that feather pattern formation is the equilibrium of stochastic interactions among multiple activators and inhibitors. While morphogens and receptors are coded by the genome, the result is based on the summed physical-chemical properties on the whole cell surface and is self-organizing. For another example...

Host Tissue and Glycan Binding Specificities of Avian Viral Attachment Proteins Using Novel Avian Tissue Microarrays

Ambepitiya Wickramasinghe, Iresha N.; de Vries, Robert P.; Eggert, Amber M.; Wandee, Nantaporn; de Haan, Cornelis A. M.; Gröne, Andrea; Verheije, Monique H.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 02/06/2015 EN
Relevância na Pesquisa
26.3%
The initial interaction between viral attachment proteins and the host cell is a critical determinant for the susceptibility of a host for a particular virus. To increase our understanding of avian pathogens and the susceptibility of poultry species, we developed novel avian tissue microarrays (TMAs). Tissue binding profiles of avian viral attachment proteins were studied by performing histochemistry on multi-species TMA, comprising of selected tissues from ten avian species, and single-species TMAs, grouping organ systems of each species together. The attachment pattern of the hemagglutinin protein was in line with the reported tropism of influenza virus H5N1, confirming the validity of TMAs in profiling the initial virus-host interaction. The previously believed chicken-specific coronavirus (CoV) M41 spike (S1) protein displayed a broad attachment pattern to respiratory tissues of various avian species, albeit with lower affinity than hemagglutinin, suggesting that other avian species might be susceptible for chicken CoV. When comparing tissue-specific binding patterns of various avian coronaviral S1 proteins on the single-species TMAs, chicken and partridge CoV S1 had predominant affinity for the trachea, while pigeon CoV S1 showed marked preference for lung of their respective hosts. Binding of all coronaviral S1 proteins was dependent on sialic acids; however...

Tolerance Induction after Organ Transplantation, “Delayed Tolerance,” Via the Mixed Chimerism Approach: Planting Flowers in a Battle Field

Yamada, Yohei; Benichou, Gilles A.; Cosimi, A. Benedict; Kawai, Tatsuo
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
26.1%
We have previously reported that peri-transplant conditioning leads to successful induction of renal allograft tolerance via the mixed chimerism approach in nonhuman primates (NHP) and humans. However, this strategy requires treatments beginning six days prior to transplantation, which limits its relevance only to living donor transplant recipients. To extend the clinical applicability of this approach, we developed a novel regimen “delayed tolerance,” with which the recipient initially undergoes organ transplantation with conventional immunosuppression, followed by conditioning and donor bone marrow transplantation (DBMT) at a later date. This approach might be likened to “planting flowers in a battle field.” That is, the recipient’s immunologic environment after organ transplantation is like a battlefield filled with hostile innate and adaptive immune-responses directed against donor antigeneic specificities. Implanting fragile donor hematopoietic progenitors into this environment and encouraging them to bloom in this vicious field requires special treatments. In our NHP studies recently published in The American Journal of Transplantation, we showed that such “delayed tolerance,” in fact, can be induced in NHP through the mixed chimerism approach...

La sécurité des xénogreffons : une normativité à bâtir

Claprood, Sonia
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
Relevância na Pesquisa
26.02%
La xénotransplantation, soit la transplantation de cellules, de tissus ou d'organes d'origine animale chez l'homme, est envisagée comme solution à la pénurie d'organes. Toutefois, cette technologie pourrait être à l'origine de nouvelles maladies. D'où la nécessité d'avoir des mesures visant tant la santé des animaux fournisseurs que la qualité et la sécurité des xénogreffons pour minimiser les risques de transmission de maladies de l'animal à l'homme, appelées xénozoonoses. L'objet de ce mémoire est de vérifier si les normes existantes au Canada et au Québec sont appropriées pour assurer la sécurité des receveurs et de la population. Nous avons d'abord examiné les normes susceptibles de s'appliquer à la surveillance et au contrôle de la santé des animaux fournisseurs. Ne visant que les maladies connues, elles ne répondent pas aux spécificités de la xénotransplantation. Quant aux xénogreffons, leur qualification pose problème: drogues ou instruments. Cette incertitude pourrait affecter l'uniformité des décisions relatives à leur qualité et à leur sécurité. Nous avons aussi étudié la Proposition d'une Norme canadienne pour la xénotransplantation. Cette dernière pourrait certes pallier la situation d'inadéquation de l'encadrement normatif existant au Canada. Une comparaison de cette norme canadienne avec les recommandations de l'OMS et les mesures en place aux ÉtatsUnis nous permet de suggérer comment la bonifier. Il ressort de notre étude que l'encadrement normatif canadien visant la sécurité des xénogreffons demeure à bâtir. Un élément essentiel à considérer dans son élaboration est la nécessité d'instaurer des systèmes de contrôle adéquats et compatibles à l'échelle planétaire.; Xenotransplantation that is...

Role of non-enzymatic antioxidants on the bivalves' adaptation to environmental mercury: Organ-specificities and age effect in Scrobicularia plana inhabiting a contaminated lagoon

Ahmad, I.; Mohmood, I.; Coelho, J. P.; Pacheco, M.; Santos, M. A.; Duarte, A. C.; Pereira, E.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.33%
This study aimed to investigate the role of non-enzymatic antioxidants on adaptive skills over time in the bivalve Scrobicularia plana environmentally exposed to mercury. Inter-age (2+, 3+, 4+, 5+ year old) and organ-specific (gills, digestive gland) approaches were applied in bivalves collected from moderately and highly contaminated sites at Ria de Aveiro (Portugal). S. plana's adaptive skills were dependent on the contamination extent; under moderate contamination scenario, the intervention of the different antioxidants took place harmoniously, evidencing an adjustment capacity increasing with the age. Under higher contamination degree, S. plana failed to cope with mercury threat, showing an age-dependent deterioration of the defense abilities. In organ-specific approach, the differences were particularly evident for thiol-compounds, since only gills displayed the potential to respond to moderate levels by increasing non-protein thiols and total glutathione. Under high contamination degree, both organs were unable to increase thiol-compounds, which were compensated by the ascorbic acid elevation.

Mercury accumulation patterns and biochemical endpoints in wild fish (Liza aurata): A multi-organ approach

Mieiro, C. L.; Duarte, A. C.; Pereira, M. E.; Pacheco, M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.22%
The integration of bioaccumulation and effect biomarkers in fish has been proposed for risk evaluation of aquatic contaminants. However, this approach is still uncommon, namely in the context of mercury contamination. Furthermore, a multi-organ evaluation allows an overall account of the organisms' condition. Having in mind the organs' role on metal toxicokinetics and toxicodynamics, gills, liver and kidney of golden grey mullet (Liza aurata) were selected and mercury accumulation, antioxidant responses and peroxidative damage were assessed. Two critical locations in terms of mercury occurrence were selected from an impacted area of the Ria de Aveiro, Portugal (L1, L2), and compared with a reference area. Although kidney was the organ with the highest mercury load, only gills and liver were able to distinguish mercury accumulation between reference (R) and contaminated stations. Each organ demonstrated different mercury burdens, whereas antioxidant responses followed similar patterns. Liver and kidney showed an adaptive capacity to the intermediate degree of contamination/accumulation (L1) depicted in a catalase activity increase. In contrast, none of the antioxidants was induced under higher contamination/accumulation (L2) in any organ...

Organ-related and malignancy-associated reactivity of cancer patients' leucocytes: a leucocyte migration study with tumour and foetal extracts.

Matzku, S.; Zöller, M.; Ikinger, U.; Price, M. R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1980 EN
Relevância na Pesquisa
26.25%
Leucocytes from patients with a variety of tumours including gastric, colorectal, lung, kidney and mammary cancer, were tested in the leucocyte migration test (LMT) against organ-related and non-organ-related tumour and foetal extracts. The reactivity of cancer patients' leucocytes against a panel of organ-related tumour extracts was found to be 71-93%, depending on the tumour system tested. Cross-reactivity with a panel on non-organ-related tumour extracts was found in 0-38% of patients. Corresponding patterns of reactivity were obtained by testing patients' leucocytes against human foetal organ extracts; pathological migration indices (MI) were found in 70% of tests in which patients' leucocytes were reacted with organ-related extracts, and in 16% of tests with non-organ-related extracts. The data strongly support the concept that patients' leucocytes are sensitized to cross-reactive foetal determinants of organ-related specificities. Furthermore, it is proposed that foetal extracts as inducers of lymphokine production in presensitized lymphocytes could be used efficiently and reproducibly as a source of foetal antigen, as well as in the clinical application of the LMT procedure.

P25 gene regulation in Bombyx mori silk gland: two promoter-binding factors have distinct tissue and developmental specificities.

Durand, B; Drevet, J; Couble, P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1992 EN
Relevância na Pesquisa
26.06%
The gene encoding the silk protein P25 is expressed in the posterior silk gland of Bombyx mori with strict territorial and developmental specificities. The cis-acting regulatory elements previously located within the 441-bp 5' proximal sequence of the gene were examined for protein-binding capacities. We identified two factors, BMFA and SGFB, that lead to prominent band shifts and the target sites for which are included in a region homologous to the fibroin gene enhancer sequence. Analysis of the tissue-specific incidence of both factors showed that BMFA is ubiquitous, whereas SGFB is restricted to the silk gland cells. However, SGFB was found in both posterior and middle silk gland cells and therefore likely directs organ-specific, but not territory-specific, expression. Developmental studies throughout the fourth larval molt, at which the P25 gene status changes from derepressed to repressed, revealed that BMFA is reversibly modified at the transition from intermolt to molt. Indeed, the preexisting BMFA is replaced by a structurally related factor, BMFA', during the 2 h following head capsule apolysis. The exact temporal coincidence of this conversion with the onset of gene repression suggests that BMFA' is involved in transcription inactivation and likely results from a transduction process initiated by the hormonal change at molting.

Expression pattern of glycoconjugates in the Bidderian and ovarian follicles of the Brazilian toad Bufo ictericus analyzed by lectin histochemistry

Farias,C. F.; Azevedo,R. A.; Brito-Gitirana,L.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2006 EN
Relevância na Pesquisa
26.15%
The Bidder's organ and ovary of the Brazilian toad Bufo ictericus were studied by light microscopy, using hematoxylin-eosin (HE) and periodic acid Schiff (PAS) staining. The expression and distribution of carbohydrate moieties was analyzed by lectin histochemistry, using 8 lectins with different carbohydrate specificities: Ulex europaeus (UEA I), Lens culinaris (LCA), Erythrina cristagalli (ECA), Arachis hypogaea (PNA), Ricinus communis (RCA I), Aleuria aurantia (AAA), Triticum vulgaris (WGA), and Glycine maximum (SBA). The results showed that the Bidderian zona pellucida presented alpha-mannose, alpha-L-fucose, beta-D-galactose, N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. The Bidderian follicular cells showed the presence of beta-D-galactose and N-acetyl-D-glucosamine. In the extracellular matrix, alpha-mannose and alpha/beta-N-acetyl-galactosamine residues were detected. The ovarian zona pellucida showed alpha-L-fucose, N-acetyl-D-glucosamine, alpha/beta-N-acetyl-galactosamine residues, and alpha-mannose and N-acetyl-D-glucosamine residues were detected in the follicular cells. Thus, the zona pellucida in both organs contains N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. alpha-L-fucose residues were detected in the zona pellucida of both organs...

Mapping the protein regions responsible for the functional specificities of the Arabidopsis MADS domain organ-identity proteins

Krizek, Beth Allyn; Meyerowitz, Elliot M.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 30/04/1996
Relevância na Pesquisa
26.36%
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.