Tissue culture propagation alters plant-microbe interactions in tobacco rhizosphere

We have compared properties of roots from different lines (genotypes) of tobacco raised either in tissue culture or grown from seed. The different lines included unmodified plants and plants modified to express reduced activity of the enzyme cinnamoyl-CoA reductase, which has a pivotal role in lignin biosynthesis. The size and structure of the rhizosphere microbial community, characterized by adenosine triphosphate and phospholipid fatty acid analyses, were related to root chemistry (specifically the soluble carbohydrate concentration) and decomposition rate of the roots. The root material from unmodified plants decomposed faster following tissue culture compared with seed culture, and the faster decomposing material had significantly higher soluble carbohydrate concentrations. These observations are linked to the larger microbial biomass and greater diversity of the rhizosphere communities of tissue culture propagated plants.

Promoting sustainability: Efficacy and adoption of tobacco-based insecticides in Nigeria

The promotion of technologies seen to be aiding in the attainment of agricultural sustainability has been Popular amongst Northern-based development donors for many years. One of these, botanical insecticides (e.g., those based on neem, Pyrethrum and tobacco) have been a particular favorite as they are equated with being 'natural' and hence less damaging to human health and the environment. This paper describes the outcome of interactions between one non-government organisation (NGO), the Diocesan Development Services (DDS), based in Kogi State, Nigeria, and a major development donor based in Europe that led to the establishment of a programme designed to promote the Virtues of a tobacco-based insecticide to small-scale farmers. The Tobacco Insecticide Programme (TIP) began in the late 1980s and ended in 200 1, absorbing significant quantities of resource in the process. TIP began with exploratory investigations of efficacy on the DDS seed multiplication farm followed by stages of researcher-managed and farmer-managed on-farm trials. A survey in 2002 assessed adoption of the technology by farmers. While yield benefits from using the insecticide were nearly always positive and statistically significant relative to an untreated control, they were not as good as commercial insecticides. However, adoption of the tobacco insecticide by local farmers was poor. The paper discusses the reasons for poor adoption, including relative benefits in gross margin, and uses the TIP example to explore the differing power relationships that exist between donors, their field partners and farmers. (C) 2004 by The Haworth Press, Inc. All rights reserved.

Local development companies and the regeneration of Britain's cities

Efforts to decentralise the pursuit of economic and social development have increased in recent years. The authors examine the rationale for establishing local development companies in areas of high unemployment and deprivation. The broad purpose is to establish a new style of organisation that combines attributes of the public and private sectors-to adapt and integrate economic and social services to meet local needs, to champion local interests in external arenas, and to act as enabling agents to promote local investment and development. These arguments are elaborated and illustrated with reference to one of Britain's most successful local development companies, Govan Initiative. The analysis reveals important strengths of the Initiative, including its action orientation, commitment to quality, and a local leadership role, but also certain weaknesses including its limited leverage over wider policies and resource flows. Local development companies need meaningful commitment from regional and national public organisations to fulfil their potential.

Tissue culture propagation alters plant-microbe interactions in tobacco rhizosphere

We have compared properties of roots from different lines (genotypes) of tobacco raised either in tissue culture or grown from seed. The different lines included unmodified plants and plants modified to express reduced activity of the enzyme cinnamoyl-CoA reductase, which has a pivotal role in lignin biosynthesis. The size and structure of the rhizosphere microbial community, characterized by adenosine triphosphate and phospholipid fatty acid analyses, were related to root chemistry (specifically the soluble carbohydrate concentration) and decomposition rate of the roots. The root material from unmodified plants decomposed faster following tissue culture compared with seed culture, and the faster decomposing material had significantly higher soluble carbohydrate concentrations. These observations are linked to the larger microbial biomass and greater diversity of the rhizosphere communities of tissue culture propagated plants.

A review of growth for construction service companies in global markets

Throughout the developed world, professional services play an increasingly important part in an economy, with many countries showing a substantial positive trade balance for services. Yet, there has been relatively little research on construction services (CS) and, in particular, how well professional service companies (PSFs) perform in the international arena. The method for collecting services export information differs to the way in which goods and products exports data are gathered because of the intangible nature of services. Organisational growth of companies aims to share risks across different regions and sectors, however, the rapidly changing business environment challenges companies with the increasing foreign ownership and changes in procurement. The complexity of today’s international construction services organisations raises two questions: how the organisations can successfully manage growth and what are their motives for international trade. The research focuses on top UK consulting engineering companies to understand their organisational strategy, their export strategy, and drivers for overseas activities. The data will feed a model of professional services exports, which can help to inform the way services export data could be collected to better reflect the industry’s performance.

Do construction companies need to match employees' expectations?

Commitment of employees is relatively low in construction. This problem is exasperated by companies inability to attract, motivate, and retain talent that is then often channelled into other more attractive industrial sectors where the prospects, conditions and rewards are perceived to be much higher. The purpose of this study is thus primarily to develop a generic model to maximise employees' engagement, improve their motivation and increase the retention levels. To achieve this aim, the investigation looks into how perceived employment obligations and expectations impact commitment and through that organisational performance. The study is based on the postulations of Luhmann's theory of social systems with communication viewed as a constitutive element of a social system. Consequently expectations of a particular party in an employment relationship are represented in a communicative space requiring the other party's understanding in order to align expectations of both sides in the relationship. Explicitly, alignment of by an employee perceived manager's expectations determines his/ her commitment to fulfil obligations towards the manager. The result of this first stage of research is a conceptual model developed following the substantial supporting evidence in the literature and it forms the framework for mitigation of low commitment, motivation and retention of employees. The model particularly focuses on factors affecting employees' perceived expectations like reneging, incongruence and the process of communication. In the future the model will be validated using empirical data from a combination of observational and enquiry-based research. Once completed, the model will provide a framework for informing Human Resource Management policies with the aim to improve commitment of employees, increase the levels of retention and consequently improve the performance of construction organisations.

Time patterns in UK demand for alcohol and tobacco: an application of the EM algorithm

Capturing the pattern of structural change is a relevant task in applied demand analysis, as consumer preferences may vary significantly over time. Filtering and smoothing techniques have recently played an increasingly relevant role. A dynamic Almost Ideal Demand System with random walk parameters is estimated in order to detect modifications in consumer habits and preferences, as well as changes in the behavioural response to prices and income. Systemwise estimation, consistent with the underlying constraints from economic theory, is achieved through the EM algorithm. The proposed model is applied to UK aggregate consumption of alcohol and tobacco, using quarterly data from 1963 to 2003. Increased alcohol consumption is explained by a preference shift, addictive behaviour and a lower price elasticity. The dynamic and time-varying specification is consistent with the theoretical requirements imposed at each sample point. (c) 2005 Elsevier B.V. All rights reserved.

The cell wall and secretory proteome of a tobacco cell line synthesising secondary wall

The utility of plant secondary cell wall biomass for industrial and biofuel purposes depends upon improving cellulose amount, availability and extractability. The possibility of engineering such biomass requires much more knowledge of the genes and proteins involved in the synthesis, modification and assembly of cellulose, lignin and xylans. Proteomic data are essential to aid gene annotation and understanding of polymer biosynthesis. Comparative proteomes were determined for secondary walls of stem xylem and transgenic xylogenic cells of tobacco and detected peroxidase, cellulase, chitinase, pectinesterase and a number of defence/cell death related proteins, but not marker proteins of primary walls such as xyloglucan endotransglycosidase and expansins. Only the corresponding detergent soluble proteome of secretory microsomes from the xylogenic cultured cells, subjected to ion-exchange chromatography, could be determined accurately since, xylem-specific membrane yields were of poor quality from stem tissue. Among the 109 proteins analysed, many of the protein markers of the ER such as BiP, HSP70, calreticulin and calnexin were identified, together with some of the biosynthetic enzymes and associated polypeptides involved in polymer synthesis. However 53% of these endomembrane proteins failed identification despite the use of two different MS methods, leaving considerable possibilities for future identification of novel proteins involved in secondary wall polymer synthesis once full genomic data are available.

Modification of hemicellulose content by antisense down-regulation of UDP-glucuronate decarboxylase in tobacco and its consequences for cellulose extractability

Extractability and recovery of cellulose from cell walls influences many industrial processes and also the utilisation of biomass for energy purposes. The utility of genetic manipulation of lignin has proven potential for optimising such processes and is also advantageous for the environment. Hemicelluloses, particularly secondary wall xylans, also influence the extractability of cellulose. UDP-glucuronate decarboxylase produces UDP-xylose, the precursor for xylans and the effect of its down-regulation on cell wall structure and cellulose extractability in transgenic tobacco has been investigated. Since there are a number of potential UDP-glucuronate decarboxylase genes, a 490 bp sequence of high similarity between members of the family, was chosen for general alteration of the expression of the gene family. Sense and antisense transgenic lines were analysed for enzyme activity using a modified and optimised electrophoretic assay, for enzyme levels by western blotting and for secondary cell wall composition. Some of the down-regulated antisense plants showed high glucose to xylose ratios in xylem walls due to less xylose-containing polymers, while arabinose and uronic acid contents, which could also have been affected by any change in UDP-xylose provision, were unchanged. The overall morphology and stem lignin content of the modified lines remained little changed compared with wild-type. However, there were some changes in vascular organisation and reduction of xylans in the secondary walls was confirmed by immunocytochemistry. Pulping analysis showed a decreased pulp yield and a higher Kappa number in some lines compared with controls, indicating that they were less delignified, although the level of residual alkali was reduced. Such traits probably indicate that lignin was less available for removal in a reduced background of xylans. However, the viscosity was higher in most antisense lines, meaning that the cellulose was less broken-down during the pulping process. This is one of the first studies of a directed manipulation of hemicellulose content on cellulose extractability and shows both positive and negative outcomes.

Modification of hemicellulose content by antisense down-regulation of UDP-glucuronate decarboxylase in tobacco and its conscequence for cellulose extractability

Extractability and recovery of cellulose from cell walls influences many industrial processes and also the utilisation of biomass for energy purposes. The utility of genetic manipulation of lignin has proven potential for optimising such processes and is also advantageous for the environment. Hemicelluloses, particularly secondary wall xylans, also influence the extractability of cellulose. UDP-glucuronate decarboxylase produces UDP-xylose, the precursor for xylans and the effect of its down-regulation on cell wall structure and cellulose extractability in transgenic tobacco has been investigated. Since there are a number of potential UDP-glucuronate decarboxylase genes, a 490 bp sequence of high similarity between members of the family, was chosen for general alteration of the expression of the gene family. Sense and antisense transgenic lines were analysed for enzyme activity using a modified and optimised electrophoretic assay, for enzyme levels by western blotting and for secondary cell wall composition. Some of the down-regulated antisense plants showed high glucose to xylose ratios in xylem walls due to less xylose-containing polymers, while arabinose and uronic acid contents, which could also have been affected by any change in UDP-xylose provision, were unchanged. The overall morphology and stem lignin content of the modified lines remained little changed compared with wild-type. However, there were some changes in vascular organisation and reduction of xylans in the secondary walls was confirmed by immunocytochemistry. Pulping analysis showed a decreased pulp yield and a higher Kappa number in some lines compared with controls, indicating that they were less delignified, although the level of residual alkali was reduced. Such traits probably indicate that lignin was less available for removal in a reduced background of xylans. However, the viscosity was higher in most antisense lines, meaning that the cellulose was less broken-down during the pulping process. This is one of the first studies of a directed manipulation of hemicellulose content on cellulose extractability and shows both positive and negative outcomes.

Atopococcus tabaci gen. nov., sp nov., a novel Gram-positive, catalase-negative, coccus-shaped bacterium isolated from tobacco

A novel Gram-positive, aerobic, catalase-negative, coccus-shaped organism originating from tobacco was characterized using phenotypic and molecular taxonomic methods. The organism contained a cell wall murein based on L-lysine (variation A4 alpha, type L-lysine-L-glutamic acid), synthesized long-chain cellular fatty acids of the straight-chain saturated and monounsaturated types (with C(16:1)omega 9, C-16:0 and C(18:1)omega 9 predominating) and possessed a DNA G+C content of 46 mol%. Based on morphological, biochemical and chemical characteristics, the coccus-shaped organism did not conform to any presently recognized taxon. Comparative 16S rRNA gene sequencing studies confirmed the distinctiveness of the unknown coccus, with the bacterium displaying sequence divergence values of greater than 7% with other recognized Gram-positive taxa. Treeing analysis reinforced its distinctiveness, with the unidentified organism forming a relatively long subline branching at the periphery of an rRNA gene sequence cluster which encompasses the genera Alloiococcus, Allolustis, Alkalibacterium, Atopostipes, Dolosigranulum and Marinilactibacillus. Based on phenotypic and molecular phylogenetic evidence, it is proposed that the unknown organism from tobacco be classified as a new genus and species, Atopococcus tabaci gen. nov., sp. nov. The type strain of Atopococcus tabaci is CCUG 48253(T) (= CIP 108502(T)).