905 resultados para active, in nodules


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The influence of insect attack on bud fall and subsequent poor flowering in cultivated hibiscus (Hibiscus rosa-sinensis) was studied in cages and in the field in southern Queensland. Three species of Hemiptera (most importantly Aulacosternum nigrorubrum but also Nezara viridula and Tectocoris diophthalmus) caused some bud fall in 2 plantations studied. Adults of Macroura concolor suppressed flowering for long periods in spring and summer. Data from white funnel traps and counts in flowers showed that M. concolor was most active in these seasons. Methiocarb (0.75 g a.i./litre) reduced beetle numbers and increased flowering. When 15 or more adults of M. concolor occurred per bud (or flower) most buds fell and few flowers were produced, but when beetles declined to 10 or fewer many buds survived and widespread flowering occurred. Larvae fed in fallen buds and flowers and the mean duration of development of the combined immature stages was 14 days at 26 deg C. The preference of adults of M. concolor for pale coloured flowers was examined. Hibiscus plants produced most buds from December to June with lower numbers in winter and spring (July to November). Bud production in spring and early summer (September-December) varied greatly and probably contributed to poor flowering, however, even when large numbers of buds occurred very few flowers were produced because of the activities of M. concolor.

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An economic survey of the commercial operators currently active in the Queensland Coral Reef Fin-Fish Fishery has been carried out, as part of a research project aimed at evaluating alternative management options for this fishery. This paper presents the background analysis used as a basis to develop the sampling design for this survey. The background analysis focuses on activity patterns of the fleet based on effort and catch information, as well as patterns of quota ownership. Based on this information, a fishing business profile describing the micro-economic structure of fishing operations is developed. This profile, in conjunction with the qualitative information gained in undertaking the economic surveys, allows preliminary understanding of the key drivers of profitability in the CRFFF, and possible impacts of external factors on fishing operations.

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There has been a lot of effort to make Silicon optically active. In this work we examine two methods of generating nanocrystals of Silicon from bulk fragments. This approach of ours allows us to play with the shape of the nanocrystals and therefore the degeneracy of the conduction band minimum. We go on to examine whether similar sized particles with different shapes have the same physical properties, and finally whether Silicon may be rendered optically active by this route. While we do find that similar sized particles with different shapes may have different band gaps, this route of modifying the degeneracy of the conduction band minimum makes nano Si slightly optically active.

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We have generated a recombinantBombyx morinuclear polyhedrosis virus, vBmhGH, harboring the full-length human growth hormone gene (2.4-kb genomic DNA, with four introns and the signal peptide sequences) under the control of the polyhedrin promoter. BmN cells in culture infected with the recombinant virus showed the presence of RNA corresponding to the authentic growth hormone mRNA as well as its incompletly processed precusor. Electrophoretic analysis and immunoprecipitation of proteins of recombinant virus-infected BmN cells revealed the presence of the growth hormone protein. Infection of silkworm larvae with vBmhGH led to the synthesis and efficient secretion of the protein into hemolymph. The recombinant human growth hormone was biologically active in a radioreceptor competition binding assay. The secreted protein was isolated and purified to homogeneity by a single step immunoaffinity chromatography, to a specific activity of 2.4 × 104U/mg. The recombinant hGH retained the immunological and biolological properties of the native peptide. We conclude that BmNPV vectors can be used successfully for expressing chromosomal genes harboring multiple introns.

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Regional studies globally have a strong focus on understanding the causes of variation in the economic performance and wellbeing of regions and this emphasis acknowledges that the strength of the local or regional economy plays a determinant role in shaping quality of life. Regional research has been less active in considering spatial variation in other factors that are critical to individual and societal wellbeing. For example, the regional studies community has been absent from the debate on the social determinants of health and how these influences vary spatially. This paper considers the results of a cross sectional survey of Australians aged 65 and over that focussed on social connections and wellbeing. It examines regional variations in the incidence of social isolation within the older population. It finds that while the incidence of self-reported social isolation amongst older persons is broadly consistent with earlier studies, it demonstrates a spatial patterning that is unexpected. The paper considers community-building activities in addressing the impacts of social isolation, including the role of urban design, and suggests that there is a need to supplement the national overview presented there through more detailed studies focussed on individual localities.

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Salmonella enterica serovar Typhimurium is a common cause of gastroenteritis in humans and, occasionally, also causes systemic infection. During systemic infection an important characteristic of Salmonella is its ability to survive and replicate within macrophages. The outer membrane protease PgtE of S. enterica is a member of the omptin family of outer membrane aspartate proteases, which are beta-barrel proteins with five surface-exposed loops. The main goals of this study were to characterize biological substrates and pathogenesis-associated functions of PgtE and to determine the conditions where PgtE is fully active. In this study we found that PgtE requires rough lipopolysaccharide (LPS) to be functional but is sterically inhibited by the long O-antigen side chain in smooth LPS. Salmonella isolates normally are smooth with a long oligosaccharide O-antigen, and PgtE remains functionally cryptic in wild-type Salmonella cultivated in vitro. Interestingly, our results showed that due to increased expression of PgtE and to reduced length of the LPS O-antigen chains, the wild-type Salmonella expresses highly functional PgtE when isolated from mouse macrophage-like J774A.1 cells. Salmonella is thought to be continuously released from macrophages to infect new ones, and our results suggest that PgtE is functional during these transient extracellular growth phases. Six novel host protein substrates were identified for PgtE in this work. PgtE was previously known to activate human plasminogen (Plg) to plasmin, a broad-spectrum serine protease, and in this study PgtE was shown to interfere with the Plg system by inactivating the main inhibitor of plasmin, alpha2-antiplasmin. PgtE also interferes with another important proteolytic system of mammals by activating pro-matrix metalloproteinase-9 to an active gelatinase. PgtE also directly degrades gelatin, a component of extracellular matrices. PgtE also increases bacterial resistance against complement-mediated killing in human serum and enhances survival of Salmonella within murine macrophages as well as in the liver and spleen of intraperitoneally infected mice. Taken together, the results in this study suggest that PgtE is a virulence factor of Salmonella that has adapted to interfere with host proteolytic systems and to modify extracellular matrix; these features likely assist the migration of Salmonella during systemic salmonellosis.

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Double-stranded RNA (dsRNA) viruses encode only a single protein species that contains RNA-dependent RNA polymerase (RdRP) motifs. This protein is a central component in the life cycle of a dsRNA virus, carrying out both RNA transcription and replication. The architecture of viral RdRPs resembles that of a 'cupped right hand' with fingers, palm and thumb domains. Those applying de novo initiation have additional structural features, including a flexible C-terminal domain that constitutes the priming platform. Moreover, viral RdRPs must be able to interact with the incoming 3'-terminus of the template and position it so that a productive binary complex is formed. Bacteriophage phi6 of the Cystoviridae family is to date one of the best studied dsRNA viruses. The purified recombinant phi6 RdRP is highly active in vitro and possesses both RNA replication and transcription activities. The extensive biochemical observations and the atomic level crystal structure of the phi6 RdRP provides an excellent platform for in-depth studies of RNA replication in vitro. In this thesis, targeted structure-based mutagenesis, enzymatic assays and molecular mapping of phi6 RdRP and its RNA were used to elucidate the formation of productive RNA-polymerase binary complexes. The positively charged rim of the template tunnel was shown to have a significant role in the engagement of highly structured ssRNA molecules, whereas specific interactions further down in the template tunnel promote ssRNA entry to the catalytic site. This work demonstrated that by aiding the formation of a stable binary complex with optimized RNA templates, the overall polymerization activity of the phi6 RdRP can be greatly enhanced. Furthermore, proteolyzed phi6 RdRPs that possess a nick in the polypeptide chain at the hinge region, which is part of the extended loop, were better suited for catalysis at higher temperatures whilst favouring back-primed initiation. The clipped C-terminus remains associated with the main body of the polymerase and the hinge region, although structurally disordered, is involved in the control of C-terminal domain displacement. The accumulated knowhow on bacteriophage phi6 was utilized in the development of two technologies for the production of dsRNA: (i) an in vitro system that combines the T7 RNA polymerase and the phi6 RdRP to generate dsRNA molecules of practically unlimited length, and (ii) an in vivo RNA replication system based on restricted infection with phi6 polymerase complexes in bacterial cells to produce virtually unlimited amounts of dsRNA. The pools of small interfering RNAs derived from dsRNA produced by these systems were validated and shown to efficiently decrease the expression of both exogenous and endogenous targets.

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In the presence of ATP, recA protein forms a presynaptic complex with single-stranded DNA that is an obligatory intermediate in homologous pairing. Presynaptic complexes of recA protein and circular single strands that are active in forming joint molecules can be isolated by gel filtration. These isolated active complexes are nucleoprotein filaments with the following characteristics: (i) a contour length that is at least 1.5 times that of the corresponding duplex DNA molecule, (ii) an ordered structure visualized by negative staining as a striated filament with a repeat distance of 9.0 nm and a width of 9.3 nm, (iii) approximately 8 molecules of recA protein and 20 nucleotide residues per striation. The widened spacing between bases in the nucleoprotein filament means that the initial matching of complementary sequences must involve intertwining of the filament and duplex DNA, unwinding of the latter, or some combination of both to equalize the spacing between nascent base pairs. These experiments support the concept that recA protein first forms a filament with single-stranded DNA, which in turn binds to duplex DNA to mediate both homologous pairing and subsequent strand exchange.

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When E. coli single-stranded DNA binding protein (SSB) coats single-stranded DNA (ssDNA) in the presence of 1 mM MgCl2 it inhibits the subsequent binding of recA protein, whereas SSB binding to ssDNA in 12 mM MgCl2 promotes the binding of recA protein. These two conditions correspond respectively to those which produce 'smooth' and 'beaded' forms of ssDNA-SSB filaments. By gel filtration and immunoprecipitation we observed active nucleoprotein filaments of recA protein and SSB on ssDNA that contained on average 1 monomer of recA protein per 4 nucleotides and 1 monomer of SSB per 20-22 nucleotides. Filaments in such a mixture, when digested with micrococcal nuclease produced a regular repeating pattern, approximately every 70-80 nucleotides, that differed from the pattern observed when only recA protein was bound to the ssDNA. We conclude that the beaded ssDNA-SSB nucleoprotein filament readily binds recA protein and forms an intermediate that is active in the formation of joint molecules and can retain substantially all of the SSB that was originally bound.

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At any given time in the field of early childhood, there are discourses at play, producing images of children, and these ways of seeing children might be competing, colliding and/or complementing each other. It is fairly widely accepted that in many countries there are versions of dominant discourses that shape and are shaped by current practices in the field of early childhood. These include (1) romantic notions of children running free and connecting with nature and (2) the ‘Bart Simpson’ version of the naughty, cute or savage child, untamed and in need of civilising. These are far from being the only two discursive constructions of children present in current policies and practices. If early childhood professionals are to be active in shaping and implementing policies that affect their work and workforce, it is important that they are aware of the forces at play. In this article, we point to another powerful discourse at play in the Australian context of early childhood education, the image of children as economic units: investments in the future. We show how a ‘moment of arising’ in contemporary policy contexts, dominated by neoliberal principles of reform and competition, has charged early childhood educators in Australia with the duties of a ‘broker’, ensuring that young children are worth the investment. In this article, we begin with (1) a key policy document in early childhood education in Australia and examine the discursive affordances which shape the document. Next, (2) we pinpoint the shifts in how the work of child care is perceived by interrogating this key policy document through a methodology of discursive analysis. We then turn attention (3) to the work of this policy document along with other discourses which directly affect images of children and the shaping role these have on the work of educators. We conclude with (4) a consideration of how the work of early childhood professionals has come to be shaped by this economic discourse, and how they are being required to both work within the policy imperatives and likely to resist this new demand of them.

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Normal growth and development require the precise control of gene expression. Transcription factors are proteins that regulate gene expression by binding specific sequences of DNA. Abnormalities in transcription are implicated in a variety of human diseases, including cancer, endocrine disorders and birth defects. Transcription factor GATA4 has emerged as an important regulator of normal development and function in a variety of endoderm- and mesoderm- derived tissues, including gut, heart and several endocrine organs, such as gonads. Mice harboring a null mutation of Gata4 gene die during embryogenesis due to failure in heart formation, complicating the study of functional role of GATA4 in other organs. However, the expression pattern of GATA4 suggests it may play a role in the regulation of ovarian granulosa cell development, function and apoptosis. This premise is supported by in vitro studies showing that GATA4 regulates several steroidogenic enzymes as well as auto-, para- and endocrine signaling molecules important for granulosa cell function. This study assessed the in vivo role of GATA4 for granulosa cell function by utilizing two genetically modified mouse strains. The findings in the GATA4 deficient mice included delayed puberty, impaired fertility and signs of diminished estrogen production. At the molecular level, the GATA4 deficiency leads to attenuated expression of central steroidogenic genes, Steroidogenic acute regulatory protein (StAR), Side-chain cleavage (SCC), and aromatase as a response to stimulations with exogenous gonadotropins. Taken together, these suggest GATA4 is necessary for the normal ovarian function and female fertility. Programmed cell death, apoptosis, is a crucial part of normal ovarian development and function. In addition, disturbances in apoptosis have been implicated to pathogenesis of human granulosa cell tumors (GCTs). Apoptosis is controlled by extrinsic and intrinsic pathways. The intrinsic pathway is regulated by members of Bcl-2 family, and its founding member, the anti-apoptotic Bcl-2, is known to be important for granulosa cell survival. This study showed that the expression levels of GATA4 and Bcl-2 correlate in the human GCTs and that GATA4 regulates Bcl-2 expression, presumably by directly binding to its promoter. In addition, disturbing GATA4 function was sufficient to induce apoptosis in cultured GCT- derived cell line. Taken together, these results suggest GATA4 functions as an anti-apoptotic factor in GCTs. The extrinsic apoptotic pathway is controlled by the members of tumor necrosis factor (TNF) superfamily. An interesting ligand of this family is TNF-related apoptosis-inducing ligand (TRAIL), possessing a unique ability to selectively induce apoptosis in malignant cells. This study characterized the previously unknown expression of TRAIL and its receptors in both developing and adult human ovary, as well as in malignant granulosa cell tumors. TRAIL pathway was shown to be active in GCTs suggesting it may be a useful tool in treating these malignancies. However, more studies are required to assess the function of TRAIL pathway in normal ovaries. In addition to its ability to induce apoptosis in GCTs, this study revealed that GATA4 protects these malignancies from TRAIL-induced apoptosis. GATA4 presumably exerts this effect by regulating the expression of anti-apoptotic Bcl-2. This is of particular interest as high expression of GATA4 is known to correlate to aggressive GCT behavior. Thus, GATA4 seems to protect GCTs from endogenous TRAIL by upregulating anti-apoptotic factors such as Bcl-2.

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This thesis has two items: biofouling and antifouling in paper industry. Biofouling means unwanted microbial accumulation on surfaces causing e.g. disturbances in industrial processes, contamination of medical devices or of water distribution networks. Antifouling focuses on preventing accumulation of the biofilms in undesired places. Deinococcus geothermalis is a pink-pigmented, thermophilic bacterium, and extremely resistant towards radiation, UV-light and desiccation and known as a biofouler of paper machines forming firm and biocide resistant biofilms on the stainless steel surfaces. The compact structure of biofilm microcolonies of D. geothermalis E50051 and the adhesion into abiotic surfaces were investigated by confocal laser scanning microscope combined with carbohydrate specific fluorescently labelled lectins. The extracellular polymeric substance in D. geothermalis microcolonies was found to be a composite of at least five different glycoconjugates contributing to adhesion, functioning as structural elements, putative storages for water, gliding motility and likely also to protection. The adhesion threads that D. geothermalis seems to use to adhere on an abiotic surface and to anchor itself to the neighbouring cells were shown to be protein. Four protein components of type IV pilin were identified. In addition, the lectin staining showed that the adhesion threads were covered with galactose containing glycoconjugates. The threads were not exposed on planktic cells indicating their primary role in adhesion and in biofilm formation. I investigated by quantitative real-time PCR the presence of D. geothermalis in biofilms, deposits, process waters and paper end products from 24 paper and board mills. The primers designed for doing this were targeted to the 16S rRNA gene of D. geothermalis. We found D. geothermalis DNA from 9 machines, in total 16 samples of the 120 mill samples searched for. The total bacterial content varied in those samples between 107 to 3 ×1010 16S rRNA gene copies g-1. The proportion of D. geothermalis in those same samples was minor, 0.03 1.3 % of the total bacterial content. Nevertheless D. geothermalis may endanger paper quality as its DNA was shown in an end product. As an antifouling method towards biofilms we studied the electrochemical polarization. Two novel instruments were designed for this work. The double biofilm analyzer was designed for search for a polarization program that would eradicate D. geothermalis biofilm or from stainless steel under conditions simulating paper mill environment. The Radbox instrument was designed to study the generation of reactive oxygen species during the polarization that was effective in antifouling of D. geothermalis. We found that cathodic character and a pulsed mode of polarization were required to achieve detaching D. geothermalis biofilm from stainless steel. We also found that the efficiency of polarization was good on submerged, and poor on splash area biofilms. By adding oxidative biocides, bromochloro-5,5-dimethylhydantoin, 2,2-dibromo-2-cyanodiacetamide or peracetic acid gave additive value with polarization, being active on splash area biofilms. We showed that the cathodically weighted pulsed polarization that was active in removing D. geothermalis was also effective in generation of reactive oxygen species. It is possible that the antifouling effect relied on the generation of ROS on the polarized steel surfaces. Antifouling method successful towards D. geothermalis that is a tenacious biofouler and possesses a high tolerance to oxidative stressors could be functional also towards other biofoulers and applicable in wet industrial processes elsewhere.

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In smaller countries where the key players in construction IT development tend to know each other personally and where public R&D funding is concentrated to a few channels, IT roadmaps and strategies would seem to have a better chance of influencing development than in the bigger industrial countries. In this paper Finland and the RATAS-project is presented as a historical case illustrating such impact. RATAS was initiated as a construction IT roadmap project in 1985, involving many of the key organisations and companies active in construction sector development. Several of the individuals who took an active part in the project have played an important role in later developments both in Finland and on the international scene. The central result of RATAS was the identification of what is nowadays called Building Information Modelling (BIM) technology as the central issue in getting IT into efficient use in the construction sector. BIM, which earlier was referred to as building product modelling, has been a key ingredient in many roadmaps since and the subject of international standardisation efforts such as STEP and IAI/IFCs. The RATAS project can in hindsight be seen as a forerunner with an impact which also transcended national borders.

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Mainstream research on management generally continues to ignore gender relations. Even so, over recent years there has been a major growth of international research on gender relations in organizations. Yet, most of this has focused on gender relations in lower or middle levels rather than at the apex of the organization. This book draws on research on gender policies, structures and practices of management in large Finnish corporations. It builds on earlier survey work of gender policies in the 100 largest corporations in Finland, to examine, through qualitative interviews, more detailed gendered processes in seven selected corporations. These represent corporations that are ‘relatively active’, ‘moderately active’, and ‘not active’ in relation to gender equality. Key issues include contrasts between formal policies and organizational practices; different corporate contexts and individual managers’ views; definition and scope of gender policy; and the relation of gender policies and diversity policy. This focus on gender policies is understood and located within organizational structures, most obviously gendered corporate hierarchies. Important structures include national context in relation to transnationalization, relations of headquarters and subsidiaries, and interrelations of management, policy development and policy implementation. Gender relations in practice and gender practices are considered in more detail. These women and men managers operate at the intersections of gendered transnational managerial work, careers and family-type relations, including marriage and children, or lack thereof. Women and men managers may be part of the same management levels or management teams, but have totally different family-type situations and gendered experiences. Interconnections of management, domestic life and transnationalizations are intensely gendered matters. The debate on the public/private continues to be important for both gender relations and organizational relations, but complicated through transnationalizations. The modern transnational corporation is considered in terms of gender divisions and gender power, with particular reference to top management. The concluding discussion notes implications for research and policy.

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Changes in MAPK activities were examined in the corpus luteum (CL) during luteolysis and pregnancy, employing GnRH antagonist (Cetrorelix)-induced luteolysis, stages of CL, and hCG treatment to mimic early pregnancy as model systems in the bonnet monkey. We hypothesized that MAPKs could serve to phosphorylate critical phosphoproteins to regulate luteal function. Analysis of several indices for structural (caspase-3 activity and DNA fragmentation) and functional (progesterone and steroidogenic acute regulatory protein expression) changes in the CL revealed that the decreased luteal function observed during Cetrorelix treatment and late luteal phase was associated with increased caspase-3 activity and DNA fragmentation. As expected, human chorionic gonadotropin treatment dramatically increased luteal function, but the indices for structural changes were only partially attenuated. All three MAPKs appeared to be constitutively active in the mid-luteal-phase CL, and activities of ERK-1/2 and p38-MAPK (p38), but not Jun N-terminal kinase (JNK)-1/2, decreased significantly (P < 0.05) within 12 - 24 h after Cetrorelix treatment. During the late luteal phase, in contrast to decreased ERK-1/2 and p38 activities, JNK-1/2 activities increased significantly (P < 0.05). Although human chorionic gonadotropin treatment increased ERK-1/2 and p38 activities, it decreased JNK-1/2 activities. The activation status of p38 was correlated with the phosphorylation status of an upstream activator, MAPK kinase-3/6 and the expression of MAPK activated protein kinase-3, a downstream target. Intraluteal administration of p38 kinase inhibitor (SB203580), but not MAPK kinase-1/2 inhibitor (PD98059), decreased the luteal function. Together, these data suggest an important role for p38 in the regulation of CL function in primates.