Genetic basis for lipopolysaccharide O-antigen biosynthesis in bordetellae

Bordetella bronchiseptica and Bordetella parapertussis express a surface polysaccharide, attached to a lipopolysaccharide, which has been called O antigen. This structure is absent from Bordetella pertussis. We report the identification of a large genetic locus in B. bronchiseptica and B. parapertussis that is required for O-antigen biosynthesis. The locus is replaced by an insertion sequence in B. pertussis, explaining the lack of O-antigen biosynthesis in this species. The DNA sequence of the B. bronchiseptica locus has been determined and the presence of 21 open reading frames has been revealed. We have ascribed putative functions to many of these open reading frames based on database searches. Mutations in the locus in B. bronchiseptica and B. parapertussis prevent O-antigen biosynthesis and provide tools for the study of the role of O antigen in infections caused by these bacteria.

Formulating priorities for research in nursing education: a consensus-building approach

To expand the scientific foundation for nursing education, the National League for Nursing is establishing a national agenda for research in nursing education. This groundbreaking effort will define research priorities that can serve as a rallying point for education researchers across the nation. The goal of this consensus-building effort is to focus nursing education research efforts on discovering the core of knowledge needed to bridge education and practice as we move into the 21st century. This article describes the process being used in this historic dialogue.

Morphology of rhinoceros platelets

Basic hematological information about rhinoceros species is limited. In this study, we have determined the platelet counts and described the platelet morphology of free-living white (Ceratotherium simum) and black (Diceros bicornis) rhinoceros using light and electron microscopy. The platelet counts of the two species were similar, but there were significant differences in platelet size as well as morphology between the species. The presence of large, nondiscoid platelet forms, resembling proplatelet or stress platelet forms, were observed in both, although not as often in the white rhinoceros as in the black rhinoceros.

Update of the Human MitBASE database

Human MitBASE is a database collecting human mtDNA variants. This database is part of a greater mitochondrial genome database (MitBASE) funded within the EU Biotech Program. The present paper reports the recent improvements in data structure, data quality and data quantity. As far as the database structure is concerned it is now fully designed and implemented. Based on the previously described structure some changes have been made to optimise both data input and data quality. Cross-references with other bio-databases (EMBL, OMIM, MEDLINE) have been implemented. Human MitBASE data can be queried with the MitBASE Simple Query System (http://www.ebi.ac.uk/htbin/Mitbase/mit base.pl) and with SRS at the EBI under the 'Mutation' section (http://srs.ebi.ac.uk/srs5/). At present the HumanMitBASE node contains approximately 5000 variants related to studies investigating population polymorphisms and pathologies.

Schizophrenia, sensory gating, and nicotinic receptors

A series of human and animal investigations has suggested that altered expression and function of the alpha7-nicotinic cholinergic receptor may be responsible for the auditory sensory gating deficit characterized in schizophrenia patients and their relatives as diminished suppression of an auditory-evoked response (P50) to repeated stimuli. This finding, in conjunction with evidence for familial transmission of this sensory gating deficit, suggests a pathogenic role of the gene for the alpha7-nicotinic receptor in schizophrenia. This article considers the possible effects of this dysfunction in a broader context. Not only is this dysfunction consistent with difficulties in sensory gating, but it might also predispose patients to problems with learning efficiency and accuracy. Such learning problems could underlie schizophrenia patients' delusional thinking, hallucinations, and social dysfunction. In addition, heavy smoking in many schizophrenia patients is consistent with the high concentration of nicotine necessary to activate the receptor and with the receptor's extremely rapid desensitization. Finally, the receptor's possible role in cell growth and differentiation should be considered in connection with developmental deficits and other cellular abnormalities in schizophrenia.

Binding of the winged-helix transcription factor HNF3 to a linker histone site on the nucleosome

The transcription factor HNF3 and linker histones H1 and H5 possess winged-helix DNA-binding domains, yet HNF3 and other fork head-related proteins activate genes during development whereas linker histones compact DNA in chromatin and repress gene expression. We compared how the two classes of factors interact with chromatin templates and found that HNF3 binds DNA at the side of nucleosome cores, similarly to what has been reported for linker histone. A nucleosome structural binding site for HNF3 is occupied at the albumin transcriptional enhancer in active and potentially active chromatin, but not in inactive chromatin in vivo. While wild-type HNF3 protein does not compact DNA extending from the nucleosome, as does linker histone, site-directed mutants of HNF3 can compact nucleosomal DNA if they contain basic amino acids at positions previously shown to be essential for nucleosomal DNA compaction by linker histones. The results illustrate how transcription factors can possess special nucleosome-binding activities that are not predicted from studies of factor interactions with free DNA.

The mitBASE human dataset structure

MitBASE is a comprehensive and integrated mitochondrial genome database funded within the EU BIOTECH PROGRAM. It is a project for the development and implementation of an integrated and comprehensive database of mitochondrial data which will collect all available information from different organisms and from intraspecies variants and mutants. The present paper describes the structure of the Human dataset in mitBASE where human molecular data are distinguished from clinical and pathological data. MitBASE home page address is: http://www.ebi.ac.uk/htbin/Mitbase/mitb ase.pl

Susceptibility of stromelysin 1-deficient mice to collagen-induced arthritis and cartilage destruction

OBJECTIVE

It has long been proposed that stromelysin is one of the major degradative matrix metalloproteinases responsible for the loss of cartilage in rheumatoid arthritis (RA) and osteoarthritis (OA). This hypothesis was tested by examining the arthritic paws of stromelysin 1 (SLN1)-deficient mice for loss of cartilage and for generation of neoepitopes that would be indicative of aggrecan cleavage.

METHODS

The SLN1 gene was inactivated in murine embryonic stem cells, and knockout mice deficient in SLN1 activity were bred onto the B10.RIII background. The incidence and severity of collagen-induced arthritis (CIA) were compared in wild-type and knockout mice. Paws from mice with CIA were examined for loss of cartilage and for proteoglycan staining, as well as for the generation of the neoepitope FVDIPEN341.

RESULTS

SLN1-deficient mice developed CIA, as did the wild-type N2 mice. Histologic analyses demonstrated no significant differences among the B10.RIII, wild-type, and knockout mice in loss of articular cartilage and proteoglycan staining. No decrease in the FVDIPEN341 epitope was observed in the SLN1-deficient mice.

CONCLUSION

Disruption of the SLN1 gene neither prevents nor reduces the cartilage destruction associated with CIA. Moreover, SLN1 depletion does not prevent the cleavage of the aggrecan Asn341-Phe342 bond.

Umbilical cord blood transplants: treatment for selected hematologic and oncologic diseases

Umbilical cord blood transplantation is a rapidly growing form of treatment for many types of cancer and hematologic disorders. The concepts behind the use of umbilical cord blood transplantation are based on information gained from experience in bone marrow transplantation. Previously discarded as human waste, the blood in the umbilical cord remnant and the placenta has been observed to be rich in hematopoietic stem cells. Techniques for collecting these stem cells from the placenta may vary among the institutions, physicians, and other health care providers, including midwives and nurse practitioners, involved with this procedure. This source of hematopoietic stem cells in transplantation has many advantages, disadvantages, and controversies associated with its use.

Morphological evidence for infection of impala, Aepyceros melampus, platelets by a rickettsia-like organism

Ultrastructural studies revealed the presence of a parasite, believed to be Ehrlichia platys, in the blood platelets of impala. At the time of blood sampling all the animals appeared healthy. This is the first report on the presence of this rickettsia in these animals, previously described in canine platelets.

Targeted disruption of the tumor necrosis factor-alpha gene: metabolic consequences in obese and nonobese mice

To address the hypothesis that tumor necrosis factor (TNF)-alpha has a role in obesity-associated insulin resistance or the regulation of in vivo lipid metabolism, mice with targeted disruption of the TNF-alpha gene were generated and studied. The absence of TNF-alpha protein in TNF-null (-/-) mice was confirmed. Lean or obese (gold-thioglucose [GTG]-injected) homozygous (-/-) mice were compared with lean or obese age- and sex-matched wild-type (+/+) mice derived from the same line at 13, 19, and 28 weeks of age. The following parameters were significantly affected in lean -/- versus +/+ mice: Body weight was not affected until week 28 (decreased by 14%); epididymal fat pad weight also decreased (25%) at this time, as did percentage body fat (16%), while percentage body protein was increased 13%. Fed plasma insulin levels decreased 47% (28 weeks), triglyceride levels decreased (all three ages; maximum 35% at 19 weeks), and fed plasma leptin decreased 33% (28 weeks). Fasting glucose was slightly (10%) reduced, but the glucose response to an oral glucose tolerance test (OGTT) was not affected. There was a trend (NS) toward increased total adipose tissue lipoprotein lipase in -/- versus +/+ mice. GTG-treatment resulted in obese -/- and +/+ mice with equal mean body weights (42 and 58% increased weight versus lean mice). The following parameters were significantly different in obese -/- mice: fasting plasma glucose decreased 13% (28 weeks), fed plasma insulin decreased 67% (28 weeks), and insulin response to OGTT was decreased by 50%. For both groups of obese mice, glucose levels during the OGTT were substantially increased compared with those in lean mice; however, mean stimulated glucose levels were 20% lower in obese -/- versus +/+ mice. We conclude 1) that TNF-alpha functions to regulate plasma triglycerides and body adiposity and 2) that although TNF-alpha contributes to reduced insulin sensitivity in older or obese mice, the absence of TNF-alpha is not sufficient to substantially protect against insulin resistance in the GTG hyperphagic model of rodent obesity.

Impala, Aepyceros melampus, platelets: count, morphology, and morphometric observations

There is little published information regarding the platelets of impala (Aepyceros melampus). In this study we determined the platelet counts of 12 healthy adult male impalas and describe the morphology of the platelets. The platelet counts of the animals are high. Although the platelets appear to be extremely small, they have the characteristic ultrastructure of the platelets of the family Bovidae. They have few but prominent alpha-granules. Other cytoplasmic inclusions are the dense bodies, microtubules, mitochondria, and glycogen. There is no surface-connecting canalicular system present.

Regulation of the mating pheromone and invasive growth responses in yeast by two MAP kinase substrates

BACKGROUND

In the budding yeast Saccharomyces cerevisiae, components of a single mitogen-activated protein (MAP) kinase pathway transduce two distinct signals, each of which activates an independent developmental programme: peptide mating pheromones initiate the mating response, whereas nutrient limitation initiates filamentous growth. One of the MAP kinases in this pathway, Fus3, triggers mating but antagonizes filamentous growth, while the other, Kss 1, preferentially triggers filamentous growth. Both kinases activate the same transcription factor, Ste 12, which can stimulate gene expression specific to each of the developmental programmes. The precise mechanism by which these MAP kinases activate Ste 12, however, is not clear.

RESULTS

Two newly identified proteins, Rst 1 and Rst 2 (also known as Dig1 and Dig2), were found to associate physically with Fus3 and Ste12. Rst1 and Rst2 were prominent substrates in kinase reactions of Fus3 immune complexes from pheromone-treated cells. Association of Fus3 with Ste12 required Rst1 and Rst2, and activation of Fus3 by pheromone caused release of Ste12 from the Fus3 complex. Although rst1 and rst2 single mutants had no obvious phenotype, both filamentous growth and mating-specific gene expression were constitutive in rst1 rst2 double mutants. The phenotype of rst1 rst2 cells required Ste12 function, but did not require the function of upstream kinases. Consistent with Rst1 and Rst2 having a role in Ste12 regulation, both proteins were localized to the nucleus.

CONCLUSIONS

Rst1 and Rst2 repress the mating and filamentous growth responses of S. cerevisiae by directly inhibiting Ste12. Activation of Fus3 or Kss1 may cause phosphorylation-dependent release of Ste12 from Rst1/Rst2 and thereby activate Ste12-dependent transcription.

The ultrasound appearances of galactocoeles

Galactocoeles are an uncommon cause of breast masses, usually occurring in lactating women. The purpose of this study was to review the ultrasound (US) features of galactocoeles presenting to the Nottingham Breast Unit. Eight women with galactocoeles were scanned during 1994 and 1995. All the scans were abnormal, 50% of lesions were cystic or multicystic, 37% mixed cystic/solid and 13% appeared solid. A fat-fluid level was seen in only one case. Two of the cystic/solid lesions had ill defined solid components, raising the possibility of an intracystic carcinoma. All cases were confirmed by the aspiration of milk and clinical resolution following aspiration.

Ultrastructure of buffalo, Syncerus caffer, platelets: comparison with bovine and human platelets

Platelets are found in the blood of all mammals and serve the same basic hemostatic functions in all. Species differences in the morphology and activities of platelets in human and domesticated animals have been observed, but there is little published information regarding the blood pictures of wild animals. In this study, the ultrastructure of buffalo platelets was compared with that of bovine and human platelets. Buffalo platelets were found to be smaller than human platelets and intracellularly had larger alpha-granules, possessed distinctive dense granules and a more distinct microtubuli system, but they lacked the open canalicular system observed in the human type. This morphology is similar to that of cattle platelets.

A matrix metalloproteinase-generated aggrecan neoepitope as a marker of skeletal maturation and aging in cartilage

OBJECTIVE

To quantify the matrix metalloproteinase-induced neoepitope F(M/V)DIPEN (Phe-[Met/Val]-Asp-Ile-Pro-Glu-Asn341) in guinea pig and rabbit cartilage during aging.

METHODS

Cartilage was taken from the stifle joint, nasal septum, and xiphoid process in guinea pigs and rabbits at selected ages. The cartilage was then extracted and evaluated for F(M/V)DIPEN levels by radioimmunoassay.

RESULTS

In the 3 tissues studied, there were major increases in F(M/V)DIPEN levels during skeletal maturation and aging in both the guinea pig and rabbit cartilage. Except for spontaneous osteoarthritis that develops in guinea pigs with aging, increases in the neoepitope were not correlated with arthritis pathology.

CONCLUSION

Increases in the level of F(M/V)DIPEN in cartilage occur as a result of skeletal maturation and aging. This physiologic accumulation of F(M/V)DIPEN in cartilage should be considered when using the neoepitope as a disease marker in arthritis.

Health effects of passive smoking in adolescent children

OBJECTIVE AND DESIGN

To study the effects of passive smoking on health in adolescent schoolchildren by questionnaire, spirometry and laboratory investigations.

SETTING

Two schools in the Vanderbijlpark area.

PARTICIPANTS

Seven hundred and twenty-six high-school children of average age 16 years.

OUTCOME MEASURES

Lung function, serological abnormality or historical (i.e. questionnaire) evidence of ill health.

RESULTS

The prevalence of respiratory illness before and after 2 years, respiratory symptoms, earache over the past year, low birth weight and learning difficulties were found to be significantly increased in the children exposed to parenteral smoke in the home, especially those exposed to maternal smoking. Spirometric and laboratory parameters, however, were not affected by passive smoking.