We investigated the phylogenetic distribution of the SPI-1 and SPI-2 pathogenicity islands in Salmonella spp. SPI-1 was present in representatives of all eight subspecific groups, but no SPI-2-hybridizing sequences were detected in group V (S. bongori). Our data suggest that SPI-2 was acquired by S. enterica after its split from S. bongori.

The evolution of bacterial pathogenicity, heavily influenced by horizontal gene transfer, provides new virulence factors and regulatory connections that alter bacterial phenotypes. Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) are chromosomal regions that were acquired at different evolutionary times and are essential for Salmonella virulence. In the intestine of mammalian hosts, S...

The Ets transcription factor Spi-C, expressed in B cells and macrophages, is closely related to PU.1 and has the ability to recognize the same DNA consensus sequence. However, the function of Spi-C has yet to be determined. The purpose of this study is to further examine Spi-C activity in B cell development. First, using retroviral vectors to infect PU.1(-/-) fetal liver progenitors, Spi-C was ...

In the early writing on software process improvement (SPI), it was suggested that the group of people responsible for designing and implementing the SPI system should apply the principles of SPI on themselves, making sure their own processes were no less mature than the processes they were trying to improve. Looking at maturity level theory from various literature sources, it seems reasonable t...

Managing a successful Software Process Improvement (SPI) is a challenging issue that many software companies face today. Many companies have invested huge amount of money in improving their software processes. This can be confirmed through several papers that present the results of SPI programs. However, as pointed out by the literature, many of these programs have encountered difficulties to a...

Systematic Literature Review (SLR) is becoming a vital part of present day research in software process improvement (SPI). Nevertheless, there is no available study that provides detail review of the published software process improvement SLRs. Objective: The aim of this article is to classify the SLRs of SPI in order to identify the main research areas covered and evaluate the quality of the p...

The effect of the length of record on the standardized precipitation index (SPI) calculation was investigated by examining correlation coefficients, the index of agreement, and the consistency of dry/wet event categories between SPI values derived from different precipitation record lengths. The effect was also illustrated by comparing SPI values derived from different lengths of record in some...

Virulence genes located on pathogenicity islands play a crucial role in the pathogenesis of Salmonella enterica infections. Salmonella pathogenicity islands (SPI) contribute to host cell invasion and intracellular pathogenesis. At present, 12 SPI have been described. Although size, structure and function of these SPI, as well as the distribution in Salmonella subspecies and serovars can be mark...

Two deletion-substitution mutations of phage lambda, spi-113 and spi-274, are shown to remove about half of the rightward operator OR. Physiological studies show that spi-113 is still repressible. Thus, the 50 or so nucleotides of OR deleted in this mutant are not absolutely essential for repression. prm-116, which inactivates the promoter essential for the maintenance of lambda repressor synth...

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major intestinal pathogen of both humans and animals. Salmonella pathogenicity island 1 (SPI-1)-encoded virulence genes are required for S. Typhimurium invasion. While oxygen (O2) limitation is an important signal for SPI-1 induction under host conditions, how the signal is received and integrated to the central SPI-1 regulatory syst...