Identification of a haemolysin-like peptide with antibacterial activity using the draft genome sequence of Staphylococcus epidermidis strain A487

Our interest in Staphylococcus epidermidis strain A487 was prompted by the unusual nature of its inhibitory activity in screening tests against methicillin-resistant Staphylococcus aureus isolates. The inhibitory activity was detected in deferred antagonism tests only if the agar plate was preheated for at least 35 min at ≥ 55 °C before inoculation of the indicator bacteria, this phenomenon indicating possible involvement of a heat-labile immunity agent or protease. The inhibitor was purified to homogeneity by ammonium sulphate precipitation, followed by cation-exchange and reversed-phase chromatography. Tandem MS revealed a novel peptide of molecular weight 2588.4 Da. The draft genome sequence of strain A487 was determined using 454 GS FLX technology, allowing the identification of the structural gene (hlp) encoding the mature peptide MQFITDLIKKAVDFFKGLFGNK. The deduced amino acid sequence of peptide 487 exhibited 70.8% similarity to that of a putative haemolysin from Staphylococcus cohnii. Analysis of the genome of strain A487 showed several additional inhibitor-encoding genes, including hld, the determinant for staphylococcal δ-lysin. This work indicates that potentially useful inhibitors could be overlooked in agar-based inhibitor screening programmes lacking a heat pretreatment step and also highlights the utility of draft genome sequence examination in antibacterial agent discovery.     

Different patterns of evolution for duplicated DNA repair genes in bacteria of the Xanthomonadales group

Background

DNA repair genes encode proteins that protect organisms against genetic damage generated by environmental agents and by-products of cell metabolism. The importance of these genes in life maintenance is supported by their high conservation, and the presence of duplications of such genes may be easily traced, especially in prokaryotic genomes.

Results

The genome sequences of two Xanthomonas species were used as the basis for phylogenetic analyses of genes related to DNA repair that were found duplicated. Although 16S rRNA phylogenetic analyses confirm their classification at the basis of the gamma proteobacteria subdivision, differences were found in the origin of the various genes investigated. Except for lexA, detected as a recent duplication, most of the genes in more than one copy are represented by two highly divergent orthologs. Basically, one of such duplications is frequently positioned close to other gamma proteobacteria, but the second is often positioned close to unrelated bacteria. These orthologs may have occurred from old duplication events, followed by extensive gene loss, or were originated from lateral gene transfer (LGT), as is the case of the uvrD homolog.

Conclusions

Duplications of DNA repair related genes may result in redundancy and also improve the organisms' responses to environmental challenges. Most of such duplications, in Xanthomonas, seem to have arisen from old events and possibly enlarge both functional and evolutionary genome potentiality.

     

External quality assurance for cervical cytology in developing countries. Experience in Peru and Nicaragua

Given interest from the professionals concerned, an external quality assurance scheme for cervical cytology can successfully be introduced in developing countries. This is a very important precondition if screening programs are to be expanded and decreases in mortality from cervical cancer are to occur in developing countries. Nicaragua and Peru have been experimenting with an external quality assurance system adapted from the Scottish and Northern Ireland scheme. It has been received with enthusiasm and acceptance and has helped cytology laboratories in these countries focusing on quality issues. Nevertheless, a successful quality control scheme that is to result in improvements in the quality of professionals' diagnostic skills needs to be accompanied by a remedial program for subperformers.     

Research: Is resection of tumours involving the pelvic ring justified? : A review of 49 consecutive cases

INTRODUCTION: Pelvic surgery is challenging and impacts significantly on limb and visceral function, thus, raising the question "is heroic surgery justifiable". This study assessed the functional, oncologic and surgical outcomes following pelvis tumour resections. METHODS: Between 1996-2003, 49 patients (mean age 43 years) underwent pelvic tumour resections- 38 primary malignant tumours, 5 secondary tumours and 6 benign tumours. Bone tumours comprised 5 osteosarcomas, 5 Ewings sarcomas, and 12 chondrosarcomas. Of the soft tumours, 9 were of neural origin. Tumours involved the ilium, acetabulum, pubic bones, sacrum or a combination of these. Functional assessment was performed and no patient had metastases at presentation. RESULTS: There were 41 limb sparing resections and 8 hindquarter amputations. Surgical margins were intralesional (1), marginal (13), wide (26), and radical (3). Of limb sparing surgery, prosthetic reconstructions were performed in 10 patients, biologic reconstructions in 6, a combination of these in 3 and no reconstruction in others. There was 1 intraoperative death, 7 local recurrences and 19 metastases. Death from disease occurred at a mean of 14.2 months with a mean followup of 27 (1-96) months. Amputation and periacetabular resections had worse functional outcomes. Emotional acceptance was surprisingly high. CONCLUSION: Pelvic resections are complex. Functional outcome is significantly affected by surgery. Disease control is similar to limb tumours. Emotional acceptance of surgery in survivors was surprisingly high. Major pelvic resection for malignancy appears justified.     

The role of aromatase inhibitors in ameliorating deleterious effects of ovarian stimulation on outcome of infertility treatment

Clinical utilization of ovulation stimulation to facilitate the ability of a couple to conceive has not only provided a valuable therapeutic approach, but has also yielded extensive information on the physiology of ovarian follicular recruitment, endometrial receptivity and early embryo competency. One of the consequences of the use of fertility enhancing agents for ovarian stimulation has been the creation of a hyperestrogenic state, which may influence each of these parameters. Use of aromatase inhibitors reduces hyperestrogenism inevitably attained during ovarian stimulation. In addition, the adjunct use of aromatase inhibitors during ovarian stimulation reduces amount of gonadotropins required for optimum stimulation. The unique approach of reducing hyperestrogenism, as well as lowering amount of gonadotropins without affecting the number of mature ovarian follicles is an exciting strategy that could result in improvement in the treatment outcome by ameliorating the deleterious effects of the ovarian stimulation on follicular development, endometrial receptivity, as well as oocyte and embryo quality.     

DNA-DNA hybridization evidence of the rapid rate of muroid rodent DNA evolution

Single-copy nuclear DNAs (scnDNAs) of eight species of arvicoline and six species of murine rodents were compared using DNA-DNA hybridization. The branching pattern derived from the DNA comparisons is congruent with the fossil evidence and supported by comparative biochemical, chromosomal, and morphological studies. The recently improved fossil record for these lineages provides seven approximate divergence dates, which were used to calibrate the DNA-hybridization data. The average rate of scnDNA divergence was estimated as 2.5%/Myr. This is approximately 10 times the rate in the hominoid primates. These results agree with previous reports of accelerated DNA evolution in muroid rodents and extend the DNA-DNA hybridization data set of Brownell.      

Immunohistochemical localization of irisin in mole rats (Spalax leucodon)

Irisin was first identified in skeletal muscle cells. It is an exercise protein that is secreted into the circulation; it causes conversion of white adipose tissue to brown adipose tissue. We investigated irisin immunoreactivity in mole rat (Spalax leucodon) tissues. We examined cerebellum, pituitary, heart, liver, pancreas, spleen, uterus, kidney and striated muscle in female adult mole rats. Tissues were processed, embedded in paraffin, sectioned at 5 μm and stained immunohistochemically for irisin. Irisin immunostaining was detected in the cytoplasm of stained cells; the cytoplasm of Purkinje cells was unstained. We found that irisin may be synthesized in many tissues. The function of locally synthesized irisin currently is unknown.     

Tumor Necrosis Factor-α +489G/A gene polymorphism is associated with chronic obstructive pulmonary disease

Pulmonary surfactant is a complex mixture of phospholipids and proteins, which is present in the alveolar lining fluid and is essential for normal lung function. Alterations in surfactant composition have been reported in several interstitial lung diseases (ILDs). Furthermore, a mutation in the surfactant protein C gene that results in complete absence of the protein has been shown to be associated with familial ILD. The role of surfactant in lung disease is therefore drawing increasing attention following the elucidation of the genetic basis underlying its surface expression and the proof of surfactant abnormalities in ILD.     

Intraosseous angiosarcoma with secondary aneurysmal bone cysts presenting as an elusive diagnostic challenge

Angiosarcoma of bone is an exceedingly rare primary bone malignancy that can present as an aggressive osteolytic lesion. Histological diagnosis can be extremely challenging, as the pathological features often resemble that of aneurysmal bone cysts. We report an interesting and peculiar case of an intraosseous angiosarcoma that presented as a diagnostic dilemma and discuss the relevant radiological and pathologic findings.     

Human muscle sarcoplasmic reticulum function during submaximal exercise in normoxia and hypoxia.

In this study, the response of the sarcoplasmic reticulum (SR) to prolonged exercise, performed in normoxia (inspired O(2) fraction = 0.21) and hypoxia (inspired O(2) fraction = 0.14) was studied in homogenates prepared from the vastus lateralis muscle in 10 untrained men (peak O(2) consumption = 3.09 +/- 0.25 l/min). In normoxia, performed at 48 +/- 2.2% peak O(2) consumption, maximal Ca(2+)-dependent ATPase activity was reduced by approximately 25% at 30 min of exercise compared with rest (168 +/- 10 vs. 126 +/- 8 micromol.g protein(-1) x min(-1)), with no further reductions observed at 90 min (129 +/- 6 micromol x g protein(-1) x min(-1)). No changes were observed in the Hill coefficient or in the Ca(2+) concentration at half-maximal activity. The reduction in maximal Ca(2+)-dependent ATPase activity at 30 min of exercise was accompanied by oxalate-dependent reductions (P < 0.05) in Ca(2+) uptake by approximately 20% (370 +/- 22 vs. 298 +/- 25 micromol x g protein(-1) x min(-1)). Ca(2+) release, induced by 4-chloro-m-cresol and assessed into fast and slow phases, was decreased (P < 0.05) by approximately 16 and approximately 32%, respectively, by 90 min of exercise. No differences were found between normoxia and hypoxia for any of the SR properties examined. It is concluded that the disturbances induced in SR Ca(2+) cycling with prolonged moderate-intensity exercise in human muscle during normoxia are not modified when the exercise is performed in hypoxia.