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This article examines the research literature on functional assessment-based interventions for students with or at risk for emotional and behavioral disorders (E/BD) who demonstrate problem behaviors. We sought to identify any trends in the design and application of functional assessment-based interventions, with an emphasis on the types of interventions employed. We also examined the frequency with which researchers are collecting and reporting measures of procedural integrity, generalization and maintenance, and social validity. Although no specific trends emerged in the selection or implementation of interventions, several key issues in the design of research on functional assessment-based interventions with students with or at risk for E/BD are identified and discussed.

One of the more significant developments in the treatment of challenging behavior has been the development of techniques of functional assessment and intervention. Much research in this area and many of the instruments and techniques initially focused on chronic aberrant behavior of persons with severe disabilities. More recently, functional assessment has been applied to students who have or are at risk for emotional and behavioral disorders (E/BD) and who have mild or no cognitive disabilities. Studies involving functional assessment of students with E/BD and those who are at risk for E/BD are reviewed in three main areas: (1) characteristics of participants; (2) types of functional assessment procedures and instruments employed; and (3) the reliability and validity of these instruments and procedures. Issues for future research in functional assessment are detailed.

Pseudomonas aeruginosa in the lungs of cystic fibrosis (CF) patients is characterized by a series of genotypic and phenotypic changes that reflect the transition from acute to chronic infection. These include the overproduction of the exopolysaccharide alginate and the loss of complete lipopolysaccharide (LPS). LPS is a major component of the Gram-negative outer membrane and is composed of lipid A, core oligosaccharide, and O antigen. In this report, we show that the LPS defect of the P. aeruginosa chronic infection isolate 2192 is temperature sensitive. When grown at 25°C, 2192 expresses serotype O1 LPS with a moderate chain length and in reduced amounts relative to those of a wild-type serotype O1 laboratory strain (stO1). In contrast, 2192 expresses no LPS O antigen when grown at 37°C. This is the first time that a temperature-sensitive defect in O-antigen production has been reported. Using complementation analyses with a constructed wbpM deletion mutant of stO1, we demonstrate that the temperature-sensitive O-antigen production defect in 2192 is due to a mutation in wbpM, which encodes a UDP-4,6-GlcNAc dehydratase involved in O-antigen synthesis. The mutation, a deletion of a single amino acid (V636) from the extreme C terminus of WbpM, renders the protein less stable than its wild-type counterpart. This residue of WbpM, which is critical for stability and function, is located outside of the recognized domains of the protein and may provide insight into the structure-function relationship of this enzyme, which is found in all 20 serotypes of P. aeruginosa. We also identify a promoter of wbpM, map a transcriptional start site of wbpM, and show that mucoidy plays a role in the loss of expression of high-molecular-weight LPS in this CF isolate.

Pseudomonas aeruginosa in the lungs of cystic fibrosis (CF) patients is characterized by a series of genotypic and phenotypic changes that reflect the transition from acute to chronic infection. These include the overproduction of the exopolysaccharide alginate and the loss of complete lipopolysaccharide (LPS). LPS is a major component of the Gram-negative outer membrane and is composed of lipid A, core oligosaccharide, and O antigen. In this report, we show that the LPS defect of the P. aeruginosa chronic infection isolate 2192 is temperature sensitive. When grown at 25°C, 2192 expresses serotype O1 LPS with a moderate chain length and in reduced amounts relative to those of a wild-type serotype O1 laboratory strain (stO1). In contrast, 2192 expresses no LPS O antigen when grown at 37°C. This is the first time that a temperature-sensitive defect in O-antigen production has been reported. Using complementation analyses with a constructed wbpM deletion mutant of stO1, we demonstrate that the temperature-sensitive O-antigen production defect in 2192 is due to a mutation in wbpM, which encodes a UDP-4,6-GlcNAc dehydratase involved in O-antigen synthesis. The mutation, a deletion of a single amino acid (V636) from the extreme C terminus of WbpM, renders the protein less stable than its wild-type counterpart. This residue of WbpM, which is critical for stability and function, is located outside of the recognized domains of the protein and may provide insight into the structure-function relationship of this enzyme, which is found in all 20 serotypes of P. aeruginosa. We also identify a promoter of wbpM, map a transcriptional start site of wbpM, and show that mucoidy plays a role in the loss of expression of high-molecular-weight LPS in this CF isolate.

Pseudomonas aeruginosa thrives in multiple environments and is capable of causing life-threatening infections in immunocompromised patients. RsmA is a posttranscriptional regulator that controls virulence factor production and biofilm formation. In this study, we investigated the expression and activity of rsmA and the protein that it encodes, RsmA, in P. aeruginosa mucA mutant strains, which are common in chronic infections. We determined that AlgU regulates a previously unknown rsmA promoter in P. aeruginosa. Western blot analysis confirmed that AlgU controls rsmA expression in both a laboratory strain and a clinical isolate. RNase protection assays confirmed the presence of two rsmA transcripts and suggest that RpoS and AlgU regulate rsmA expression. Due to the increased amounts of RsmA in mucA mutant strains, a translational leader fusion of the RsmA target, tssA1, was constructed and tested in mucA, algU, retS, gacA, and rsmA mutant backgrounds to examine posttranscriptional activity. From these studies, we determined that RsmA is active in mucA22 mutants, suggesting a role for RsmA in mucA mutant strains. Taken together, we have demonstrated that AlgU controls rsmA transcription and is responsible for RsmA activity in mucA mutant strains. We propose that RsmA is active in P. aeruginosa mucA mutant strains and that RsmA also plays a role in chronic infections. IMPORTANCE: P. aeruginosa causes severe infections in immunocompromised patients. The posttranscriptional regulator RsmA is known to control virulence and biofilm formation. We identify a new rsmA promoter and determine that AlgU is important in the control of rsmA expression. Mutant mucA strains that are considered mucoid were used to confirm increased rsmA expression from the AlgU promoter. We demonstrate, for the first time, that there is RsmA activity in mucoid P. aeruginosa strains. Our work suggests that RsmA may play a role during chronic infections as well as acute infections.

Group IIC introns insert next to the stem-loop structure of rho-independent transcription terminators, thus avoiding intact genes. The insertion sites of 17 copies of the G.st.I1 intron from Geobacillus stearothermophilus were compared. One copy of the intron was found to interrupt an open reading frame (ORF) encoding an rRNA methylase.

Vibrio anguillarum 775 is a fish pathogen that causes a disease characterized by a fatal haemorrhagic septicaemia. It harbours the 65 kbp pJM1 plasmid, which encodes an iron sequestering system specific for the siderophore anguibactin and is essential for virulence. The genes involved in the biosynthesis of anguibactin are located on both the pJM1 plasmid and the chromosome. However, the genes for the outer-membrane receptor FatA and the other transport proteins are only carried on the plasmid. With the aim of elucidating the mechanism of ferric-anguibactin transport mediated by FatA, this work focuses on the identification of FatA amino acid residues that play a role in the transport of ferric-anguibactin, by analysing the transport kinetics of site-directed mutants. The mutations studied were located in conserved residues of the lock region, which contains a cluster of ten residues belonging to the N-terminal and barrel domains, and of the channel region of FatA, which contains conserved glycines located in the β5-β6 loop and a conserved arginine located in strand 11 of the β-barrel. In the case of the FatA lock region, it is clear that although the residues analysed in this work (R95, K130, E505 and E550) are conserved among various outer-membrane receptors, their involvement in the transport process might differ among receptors. Furthermore, it was determined that in the FatA channel region double substitutions of the conserved glycines 131 and 143 with alanine resulted in a variant receptor unable to transport ferric-anguibactin. It was also shown that the conserved arginine 428 located in strand 11 is essential for transport. The results suggest that a conformational change or partial unfolding of the plug domain occurs during ferric-anguibactin transport.

The reverse transcription of the genetic code of an RNA molecule back into a complementary DNA copy (cDNA) is usually accomplished by a specially dedicated RNA-dependent DNA polymerase called a reverse transcriptase (RT). Reverse transcription is presumed to have been a central event in the transition from the theorized ancient "RNA world" of life, in which RNA molecules served as both the source of genetic information, as well as, catalytic functions for cellular life, to the present day DNA-RNA-protein world. Even today reverse transcription continues to occur in most organisms from human cells to bacteria. For example, a wide assortment of genetic elements found in plant, animal, and microbial cells use reverse transcription for at least part of their replication or mobility. These include RNA viruses, DNA viruses, transposons, introns, and mitochondrial plasmids (Eickbush, 1994; Eickbush and Malik, 2002). More astonishing than the wide variety of retroelements that encode a RT is the colossal number of repetitive retrosequences, such as the Alu sequences, that have been generated by these elements in many eukaryotic genomes. These retrosequences are DNAs that usually do not code for RT but have clearly been produced by reverse transcription of an RNA molecule (Kazazian, 2004). In addition to the production of these "parasitic" DNAs, reverse transcription also serves a vital function for most eukaryotic organisms. Here the essential enzyme telomerase, which functions to maintain the telomere ends of chromosomes, is a type of RT (Lue, 2004). Most RTs are placed in two very broad categories based on the phylogenetic analysis of their amino acid sequence and the type of retroelement that codes for these polymerases. The first group is found in eukaryotic cells and is usually called LTR-containing retroelements because their DNA is flanked by long terminal repeat sequences. These elements include retroviruses and the virus-like retrotransposons called Ty in yeast cells. The second group is called non-LTR retroelements because they are not flanked by long terminal repeats and are a very diverse collection of elements found in both eukaryotic and prokaryotic organisms. These include the mobile group II introns, the L1 retrotransposons, and the various retroelements found in bacteria. Telomerase is phylogenetically related to the RTs from this group and is thus also included in this second category (Eickbush and Malik, 2002). Among the best characterized RTs are the polymerases from retroviruses and include the detailed crystal structure of the RT from the HIV-1 virus (Steitz, 1999). The focus of this chapter is the recently discovered RTs found in bacteria and the interesting genetic elements that encode them. These prokaryotic RTs are considered to be the ancestors of all retroelements found in eukaryotic genomes based on phylogenetic comparisons (Toor et al., 2001). In addition, the bacterial RTs are a very diverse group of proteins with a number of novel properties. Thus, these bacterial RTs represent an emerging new resource for many potential nucleic acid based technologies like RT-PCR. Prokaryotic RTs generally fall into one of three different types depending on the type of retroelement DNA that codes for these proteins. These groups or types are also in agreement with phylogenetic groupings for RTs determined by comparing their amino acid sequences. The three types of retroelements are (1) the group II introns found in both eubacterial and archaeal genomes, (2) retrons, which are also found in eubacteria and some archaea, and (3) the diversity generating retroelements that have thus far been found in the eubacteria.

Retrons are distinct DNA sequences that code for a reverse transcriptase (RT) similar to the RTs produced by retroviruses and other types of retroelements. Retron DNAs are commonly associated with prophage DNA and are found in the genomes of a wide variety of different bacteria. The retron RT is used to synthesize a strange satellite DNA known as msDNA. msDNA is actually a complex of DNA, RNA, and probably protein. It is composed of a small, single-stranded DNA, linked to a small, single-stranded RNA molecule. The 5′ end of the DNA molecule is joined to an internal guanosine residue of the RNA molecule by a unique 2′-5′ phosphodiester bond. msDNA is produced in many hundreds of copies per cell, but its function remains unknown. Although retrons are absent from the genome of most members of a population of related bacteria, retrons may not be entirely benign DNAs. Evidence is beginning to suggest that retron elements may produce small but potentially significant effects on the host cell. This includes the generation of repeated copies of the msDNA sequence in the genome, and increasing the frequency of spontaneous mutations. Because these events involve the retron RT, this may represent a source of reverse transcription in the bacterial cell. Thus, the process of reverse transcription, a force that has profoundly affected the content and structure of most eukaryotic genomes, may likewise be responsible for changes in some prokaryotic genomes.