Characterization of type IV pilus genes in Pseudomonas syringae pv. tomato DC3000

Many strains of Pseudomonas syringae produce retractile pili that act as receptors for lytic bacteriophage phi 6. As these are also characteristics of type IV pili, it was postulated that P. syringae may possess genes for type IV pilus biogenesis. A cosmid clone bank of P. syringae pv. tomato DC3000 genomic DNA was used to complement a mutant of Pseudomonas aeruginosa defective in the PilD (XcpA) prepilin peptidase gene by selection for restoration of extracellular protein secretion, a function also known to require PilD. A cosmid able to complement this mutant was also able to complement mutations in the pilB and pilC genes, suggesting that, if the organization of these genes is similar to that of P. aeruginosa, the cosmid may contain the P. syringae pilA. This was confirmed by sequencing a region from this plasmid that was shown to hybridize at low stringency to the P. aeruginosa pilA gene. The deduced P. syringae PilA polypeptide possesses the characteristic properties of the type IV pilins. Heterologous expression of the P. syringae pilA in P. aeruginosa was also shown, conferring not only phi 6 phage sensitivity to P. aeruginosa pilA mutants but also sensitivity to PO4, a lytic bacteriophage specific for the pilus of P. aeruginosa. This suggests that additional components might be present in the mature pilus of P. aeruginosa that are the true receptors for this phage. Chromosomal mutations in P. syringae pv. tomato DC3000 pilA and pilD genes were shown to abolish its sensitivity to bacteriophage phi 6. To determine the importance of P. syringae pilus in plant leaf interactions, these mutations were tested under laboratory and field conditions. Although little effect was seen on pathogenicity, culturable leaf-associated population sizes of the pilA mutant were significantly different from those of the wild-type parent. In addition, the expression of the DC3000 pilA gene appears to contribute to the UV tolerance of P. syringae and may play a role in survival on the plant leaf surface.     

Statistical Approach to Quality Control of Large Thermodynamic Databases

In chemistry and engineering, thermodynamic databases are widely used to obtain the basic properties of pure substances or mixtures. Large and reliable databases are the basis of all thermodynamic modeling of complex chemical processes or systems. However, the effort needed in the establishment, maintenance, and management of a database increases exponentially along with the size and scope of the database. Therefore, we developed a statistical modeling approach to assist an expert in the evaluation and management process, which can pinpoint various types of erroneous records in a database. We have applied this method to investigate the enthalpy, entropy, and heat capacity characteristics in a large commercial database for approximately 25,000 chemical species. Our highly successful results show that a statistical approach is a valuable tool (1) for the management of such databases and (2) to create enthalpy, entropy and heat capacity estimates for such species in which thermochemical data are not available.     

Organising for infrastructure development programmes: Governing internal logic multiplicity across organisational spaces

Programme organisations operate in complex environments under the influence of multiple institutional logics. Previous studies have focused on how these kinds of organisations respond to external demands by implementing appropriate governance structures. This, however, produces an understanding of programme organisations as being unitary and working to integrate programme activities and practices under one dominant internal institutional logic. In this paper, we study the consequences of internal logic multiplicity for the governance of programme organisations. Drawing on data from a major Danish construction programme we show how, in order to achieve its mission, the programme organisation incorporates three distinct logics into its daily activities and practices. The findings illustrate how a compartmentalised structural approach is applied to differentiate and independently deal with the three logics in structurally distinct organisational spaces. To avoid fragmentation and ensure coordination, governance mechanisms are put in place that coordinate activities and practices across the organisational spaces whilst maintaining their compartmentalisation. The paper thus contributes to the literature on programme management with insights on how the institutional context influences programme structures and operations, and how governance mechanisms are implemented to manage activities and practices across organisational spaces guided by different logics.     

A three-year follow-up of Finnish telemedicine programs

The objective of the paper is to follow-up the success of Finnish telemedicine programs identified in 1996 in a nation-wide survey. The methods used are questionnaires sent to those in charge of a total of 40 telemedicine programs identified in 1996. Of the results of the programs responding to the survey (36 out of 40, i.e., 90%), 69% were still operative at the time of the follow-up in 1999. According to the respondents, one-third of the programs were deemed to have had an impact on the working process of the organization. The majority of the programs lacked a clear effect in this respect. In only four cases out of 36, the telemedicine program was deemed to have achieved savings, three of the programs had brought about extra costs, and four were cost neutral. However, in the majority of the cases, the respondents were not able to assess the financial impart of the program. The average duration of the programs still in progress was 4.2 years and those terminated was 2.5 years. The average number of patients treated in the programs still in progress was 370, i.e., approximately 88 patients per year. Of the telemedicine programs identified three years earlier, two-thirds were still in progress during the repeat survey. The average number of patients treated per year in these programs was relatively small, suggesting that telemedicine was not very successful in replacing traditional ways of delivering patient care. In line with this, only a minority of the programs were deemed to have had an effect on the working process of the organization, and cost savings were achieved in only a handful of cases