Genetic analysis of the rgg-gtfG junctional region and its role in Streptococcus gordonii glucosyltransferase activity.

Glucans synthesized by glucosyltransferase enzymes of oral streptococci facilitate bacterial accumulation on surfaces. The Streptococcus gordonii glucosyltransferase gene, gtfG, is positively regulated by rgg, which encodes a putative cytoplasmic protein. The gtfG promoter and ribosomal binding sequences are located within a DNA inverted repeat immediately downstream of rgg. Polycistronic rgg-gtfG as well as rgg- and gtfG-specific transcripts are associated with this chromosomal region. Previous studies have shown that the rgg product acts in trans near the gtfG promoter to increase the level of gtfG transcript, but it does not affect the level of rgg-gtfG transcript. To further analyze regulation by rgg, a series of strain Challis derivatives was constructed and glucosyltransferase activities were determined. Strains in which rgg was separated from gtfG by integrated vector sequences had decreased levels of glucosyltransferase activity; plasmid-borne rgg could not increase activity to parental levels. As expected, strains with chromosomal deletions involving the rgg structural gene and either the rgg or gtfG promoter also showed decreased glucosyltransferase activity. Plasmid-borne rgg could increase glucosyltransferase activity only in strains which had a 36-bp chromosomal region beginning 72 nucleotides upstream of the gtfG transcriptional start site. Results suggest that these nucleotides, located within the 3' end of rgg, are necessary, either by direct involvement in binding or by indirectly affecting secondary structure, for Rgg to increase glucosyltransferase activity. Surprisingly, the presence of the rgg promoter upstream of this 36-bp region significantly increased the effects of plasmid-borne rgg. Implications for glucosyltransferase regulation and applicability to other rgg-like determinants are considered.

Initial characterization of the Streptococcus gordonii htpX gene.

Examination of the Streptococcus gordonii chromosomal region, which lies immediately upstream of the glucosyltransferase positive regulatory determinant rgg, revealed two open reading frames. Based on nucleotide sequences, these genes were similar to the Listeria monocytogenes lemA gene, which is involved in antigen presentation, and the Escherichia coli htpX heat shock gene, which has an unknown function. Northern hybridization analysis indicated that S. gordonii lemA and htpX genes were associated with a ca. 1.7-kb polycistronic transcript. Although levels of the lemA/htpX transcript did not increase in response to heat to levels seen with dnaK controls, insertional inactivation of htpX resulted in changes in adhesiveness, cellular morphology and detergent-extractable surface antigens in cells grown at 41 degrees C, implying that htpX may be involved in surface protein expression. Insertional inactivation of lemA and htpX indicated that, despite their proximity to rgg and the structural gene, gtfG, these upstream genes do not affect S. gordonii glucosyltransferase activity.

Characterization of the Streptococcus gordonii chromosomal region immediately downstream of the glucosyltransferase gene.

The Streptococcus gordonii glucosyltransferase gene, gtfG, is positively regulated by the upstream determinant rgg. In the present study, two ORFs, transcribed on the opposite DNA strand, were identified immediately downstream of gtfG. The first, designated dsg, shares a convergent putative transcriptional terminator with gtfG, and encodes a predicted 46 kDa transmembrane protein similar to the Yersinia enterocolitica TrsA involved in polysaccharide biosynthesis. Insertional inactivation of dsg resulted in only approximately approximately 60% of the parental level of glucosyltransferase activity. The 870 bp gene 5' to dsg is similar to the gtfG regulatory determinant. Designated rggD, this rgg-like determinant downstream of gtfG encodes a putative 33.6 kDa cytoplasmic protein. Despite their sequence similarity, the functions of rgg and rggD appear specific. Strains in which rggD was insertionally inactivated and strains containing plasmid-borne rggD had parental levels of glucosyltransferase activity. Northern blot hybridization analyses showed approximately 1.3 kb dsg-specific and approximately 1.0 kb rggD-specific mRNA transcripts associated with this region; no polycistronic transcript was observed. Although rgg-like gene products have been demonstrated to function as positive transcriptional regulators of adjacent genes in several streptococcal species, Northern blot analysis suggested that rggD did not influence the transcription of dsg or the divergent downstream ylbN-like determinant under the conditions in the present study. Comparison of this S. gordonii chromosome region to other streptococcal genomes, which do not contain the rgg/rggD-flanked region involved in glucan synthesis, raised intriguing possibilities about the origins of this chromosomal region, and also suggested that rggD might regulate a distally located gene.

Children's perceptions of homelessness.

The purpose of this study was to describe what it is like to be homeless from the school-age child's unique perspective. A convenience sample of 14 school-aged children currently living in a shelter was interviewed about their experiences with homelessness. The children described their experiences openly with vivid details, and five themes were identified in the data: (a) I am not homeless, (b) I like living in a shelter sometimes, (c) living in a shelter is hard, (d) stop the violence, and (e) I need approval. Data are presented to support how the themes were labeled. Understanding the perspectives of children who live in shelters can be an important aspect in providing care to them and their families when they are treated by nurses in hospitals, schools, and communities.

Nursing advocacy during a military operation.

Advocacy is an essential component of the registered nurse's professional role, yet experts provide no consistent definition of advocacy. The purpose of this study was to explore the experiences of military nurses as they engage in advocating practices and to describe their shared practices and common meanings. Heideggerian hermeneutic phenomenology, provided the framework and method for this study. Twenty-four U.S. Army nurses were individually interviewed and the researcher kept interview observational notes. The constant comparative method of analysis was used. The stories of these nurses revealed one constitutive pattern--safeguarding--and four related themes. The themes were advocating as protecting, advocating as attending the whole person, advocating as being the patient's voice, and advocating as preserving personhood. One conclusion was that military nurses must be prepared for the important safe-guarding role. They must be coached in how to deal with other members of the health team on the patient's behalf.

Clinical decision-making processes in perioperative nursing.

The purpose of this phenomenological study was to reveal the processes of clinical decision making by expert perioperative nurses. Six nurses with a minimum of five years experience who considered themselves to be experts in OR nursing were asked to describe perioperative situations in which they had made a difference in patient outcomes. In every situation described, an intricate pattern of concern was present and associated with further assessments. The pattern was labeled Seeing the big picture: Engendered through caring. This study provides initial documentation to support how RNs make critical contributions to the quality of perioperative patient care.

Nurses' perceptions of people who are homeless.

There are few data-based reports about the perceptions of nurses toward marginalized groups and even fewer about the transformation of perceptions. The purpose of this study was to explore nurses' perceptions of people who are homeless and to describe transforming experiences. Rich, detailed experiences of the care provided to people who were homeless were elicited through in-depth interviews with 15 nurses and nursing students. Without exception, each participant in this study indicated that listening, connecting, and understanding were important to them in changing previously held negative beliefs. However, when clients did not express appreciation or behave in expected ways, nurses became frustrated and voiced negative feelings about people who are homeless. Study findings emphasize the importance of listening and connecting with people who are different from ourselves so that our shared humanity is acknowledged and appreciated.

Changes in the carboxyl-terminal repeat region affect extracellular activity and glucan products of Streptococcus gordonii glucosyltransferase.

Glucans produced by the glucosyltransferase (GTF) of Streptococcus gordonii confer a hard, cohesive phenotype (Spp+) on colonies grown on sucrose agar plates. S. gordonii strains with specific mutations in the region of gtfG that encodes the GTF carboxyl terminus were characterized. In the parental strain Challis CH1, this region included a series of six direct repeats thought to function in glucan binding. The spontaneous mutant strain CH107 had a 585-bp deletion resulting in the loss of three internal direct repeats. Insertional mutagenesis was used to construct strain CH2RPE, which had the parental repeat region but was missing 14 carboxyl-terminal amino acids. The similarly constructed strain CH4RPE had an in-frame addition of 390 nucleotides encoding two additional direct repeats. Although strains CH1, CH2RPE, and CH4RPE all had similar levels of extracellular GTF activity, strain CH107 had less than 15% of the parental activity; however, Western blots (immunoblots) indicated that the amounts of extracellular GTF protein in all four strains were similar. 13C NMR analyses indicated that partially purified GTFs from the Spp+ strains CH1, CH2RPE, and CH4RPE all produced glucans with similar ratios of alpha1,6 and alpha1,3 glucosidic linkages, whereas the Spp- strain CH107 GTF produced primarily alpha1,6-linked glucans. Transformation of strain CH107 with pAMS57, which carries the gtfG positive regulatory determinant, rgg, increased the amount of GTF activity and GTF antibody-reactive protein ca. fivefold but did not confer a hard colony phenotype on sucrose agar plates, suggesting that the type of glucan product affects the sucrose-promoted colony phenotype.

Heterosexism in nursing education.

If we are to take seriously the challenge of teaching nursing students skills in critical thinking, as nurse educators we must examine the most difficult issues facing society and nurses. Heterosexism and the resulting homophobia are such issues. This article provides an introduction to the concepts of heterosexism and homophobia and describes how they intersect and are revealed in nursing education. The consequences of heterosexism and homophobia are illustrated using examples from our experiences as lesbian and heterosexual nurse educators. We conclude with an action plan for undermining heterosexism and homophobia.

The power of human caring: early recognition of patient problems.

The purpose of this qualitative study was to gain an understanding of the processes used by critical care nurses in the early recognition of patient problems. Patient-care narratives related by the 30 nurses who participated in the study revealed that caring, as manifested by an involved stance from the nurse, can actually heighten nurses' perceptions, thus improving assessment skills so as to allow early recognition of patient problems. This power of caring was sharply contrasted with situations where the recognition of patient problems was delayed or never occurred and that were characterized by a detached relationship between the nurse and patient. In this study, nurses confirmed that caring heightened their perceptions, improved assessment skills, and enabled the early recognition of patient problems. Clearly, practices that evolve from an involved stance from the nurse can make a difference in patient outcomes.

Living with cancer: children with extraordinary courage.

PURPOSE: To gain an understanding of the personal experience of school-age children with cancer. DESIGN: Phenomenologic. SETTING: A comprehensive pediatric cancer center in the southeastern United States. SAMPLE: 21 children (11 males and 10 females) 7-13 years of age receiving treatment for a variety of cancers. MAIN RESEARCH VARIABLES: Children's thoughts and feelings about their cancer and its treatment. FINDINGS: Common themes about what provided strength for these children during treatment emerged: "knowing" (what to expect, information about cancer, others with cancer), "caring" (for self, being cared for by family and nurses), "feeling special" (feeling unique and also struggling to feel normal), and "getting used to it" (being brave, accepting things). CONCLUSIONS: Children can demonstrate a pattern of strength and the ability to bounce back, despite stressful situations. In spite of differences in cognitive development, children can be helped to develop strength in the face of adversity. IMPLICATIONS FOR NURSING: Nurses can assist children with cancer by developing interventions that provide age-appropriate information, support their perceived specialness, and integrate the use of new interventions that decrease painful treatments.