The role of the conserved phenylalanine in the sigma54-interacting GAFTGA motif of bacterial enhancer binding proteins

σ⁵⁴-dependent transcription requires activation by bacterial enhancer binding proteins (bEBPs). bEBPs are members of the AAA+ (ATPases associated with various cellular activities) protein family and typically form hexameric structures that are crucial for their ATPase activity. The precise mechanism by which the energy derived from ATP hydrolysis is coupled to biological output has several unknowns. Here we use Escherichia coli PspF, a model bEBP involved in the transcription of stress response genes (psp operon), to study determinants of its contact features with the closed promoter complex. We demonstrate that substitution of a highly conserved phenylalanine (F85) residue within the L1 loop GAFTGA motif affects (i) the ATP hydrolysis rate of PspF, demonstrating the link between L1 and the nucleotide binding pocket; (ii) the internal organization of the hexameric ring; and (iii) σ⁵⁴ interactions. Importantly, we provide evidence for a close relationship between F85 and the −12 DNA fork junction structure, which may contribute to key interactions during the energy coupling step and the subsequent remodelling of the Eσ⁵⁴ closed complex. The functionality of F85 is distinct from that of other GAFTGA residues, especially T86 where in contrast to F85 a clean uncoupling phenotype is observed.

Analysis of cutaneous melanoma in the province of Vojvodina

PURPOSE

To analyse the incidence and mortality of melanoma in the province of Vojvodina - the north part of Serbia- from the epidemiologic and clinical point of view.

PATIENTS AND METHODS

In this retrospective study, we used databases of the Cancer Registry of Vojvodina, Oncology Institute of Vojvodina in Sremska Kamenica; Clinical Centre of Vojvodina in Novi Sad; Institute of Public Health of Vojvodina in Novi Sad; and Institute of Public Health of Serbia in Belgrade.

RESULTS

The incidence and mortality of melanoma in Vojvodina is permanently increasing over the last three decades. The number of newly diagnosed and deceased patients was higher in men and in women in Vojvodina than in central Serbia. Considering the incidence rate, the region of Vojvodina would be placed in the middle of the European countries. The results are more unfavorable with mortality, especially in male population, similar to the range of higher mortality rates among European countries.

CONCLUSION

These upsetting facts call for improvement of primary and secondary prevention. Education of the population, continuous efforts to recognize groups of population at high risk for developing melanoma and detection of early phases of the disease increases the chances for cure and significantly reduces treatment costs.

miRNAs and apoptosis: RNAs to die for

MicroRNAs (miRNAs) are small non-coding RNAs of about 18-24 nucleotides in length that negatively regulate gene expression. Discovered only recently, it has become clear that they are involved in many biological processes such as developmental timing, differentiation and cell death. Data that connect miRNAs to various kinds of diseases, particularly cancer, are accumulating. miRNAs can influence cancer development in many ways, including the regulation of cell proliferation, cell transformation, and cell death. In this review, we focus on miRNAs that have been shown to play a role in the regulation of apoptosis. We first describe in detail how Drosophila has been utilized as a model organism to connect several miRNAs with the cell death machinery. We discuss the genetic approaches that led to the identification of those miRNAs and subsequent work that helped to establish their function. In the second part of the review article, we focus on the involvement of miRNAs in apoptosis regulation in mammals. Intriguingly, many of the miRNAs that regulate apoptosis have been shown to affect cancer development. In the end, we discuss a virally encoded miRNA that influences the cell death response in the mammalian host cell. In summary, the data gathered over the recent years clearly show the potential and important role of miRNAs to regulate apoptosis at various levels and in several organisms.

Regulation of TRAIL-induced apoptosis by XIAP in pancreatic carcinoma cells

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer therapy because of its relative tumor selectivity. However, many cancers including pancreatic cancer remain resistant towards TRAIL. To develop TRAIL for cancer therapy of pancreatic carcinoma, it will therefore be pivotal to elucidate the molecular mechanisms of TRAIL resistance. Here, we identify X-linked inhibitor of apoptosis (XIAP) as a regulator of TRAIL sensitivity in pancreatic carcinoma cells. Full activation of effector caspases, loss of mitochondrial membrane potential and cytochrome c release following TRAIL treatment were markedly impaired in pancreatic carcinoma cell lines, which poorly responded to TRAIL (PaTuII, PancTu1, ASPC1, DanG), compared to TRAIL-sensitive Colo357 pancreatic carcinoma cells. Stable downregulation of XIAP by RNA interference significantly reduced survival and enhanced TRAIL-induced apoptosis in pancreatic carcinoma cells. Also, downregulation of XIAP significantly increased CD95-induced cell death. Importantly, knockdown of XIAP strongly inhibited clonogenicity of pancreatic cancer cells treated with TRAIL indicating that XIAP promotes clonogenic survival of pancreatic carcinoma cells. Thus, our findings for the first time indicate that targeting XIAP represents a promising strategy to enhance the antitumor activity of TRAIL in pancreatic cancer, which has important clinical implications.

Standardization of transrectal ultrasound-guided biopsy

Ultrasound-guided biopsy is more sensitive to biopsy performed under the digital control, because 29% of prostatic cancers are not palpable. On the other hand, at least 30% of cancers are isoechogenic, so they cannot be viewed by transrectal ultrasound examination. It means that target biopsy is not sufficient for diagnosis of localized prostatic cancer, i.e., randomized samples are needed as well. More than ten years ago, the technique of sampling the six specimens became a standard procedure to which previously harvested target specimens from suspected growths were added. Today, the expansion of biopsy protocol is recommended, by obtaining the additional specimens from peripheral lateral area, four plus two samples if the prostate has volume over 50 ml. Larger number of biopsies requires anesthesia. In order to reduce complication, the cleaning of rectal ampulla and prophylactic use of quinolone are suggested.

Correlation of high-molecular cytokeratin in tissue of prostatic cancer with Gleason score and PSA

The absence of basal cell layer of prostatic acini containing high-molecular cytokeratin, which is immunohistochemically detected by monoclonal antibody 34betaE12, is an essential diagnostic characteristic of prostatic cancer. The absence of immunohistochemical reaction in 3 or more pseudoglandular structures of prostatic tissue indicates malignant process. The percentage of immunohistochemically completely negative glandular structures was determined by semiquantitative measurement in tissue specimens obtained by TRUS biopsy of the prostate, and it was correlated with serum PSA concentration and Gleason score. The increase of percentage of glandular prostatic formations completely negative to high-molecular cytokeratin detected by 34betaE12 led to simultaneous rise of mean value of Gleason prostatic cancer score (p < 0.001) as well as the average serum PSA concentration in subjects (p < 0.05).

The application of collagen sheet in open wound healing*

The aim of this paper is describe the application of desamidated collagen as a biomaterial in order to evaluate the utility of collagen, particularly as a drug delivery device, as a haemostat, and as a wound cover. We also evaluated the utility of vitamin A, vitamin C, 50% glucose, and gentamicin locally applied onto the open wound. Any biomaterial should ensure non-toxicity to the biological environment where it is applied. We point out the utility of vitamin A, vitamin C, 50% glucose, and gentamicin locally applied onto the open wound with a biological covering. Collagen sheet is becoming evident in our ongoing studies. We are convinced that collagen sheets are very useful in first- and second-degree burns. The cost factor comes down and the pain associated with dressing can be avoided. Especially in children it is very useful since the trauma of dressing can be avoided.

The LysR-type transcriptional regulator CysB controls the repression of hslJ transcription in Escherichia coli

The LysR-type transcriptional regulator (LTTR) CysB is a transcription factor inEscherichia colicells, where as a homotetramer it binds the target promoter regions and activates the genes involved in sulphur utilization and sulphonate-sulphur metabolism, while negatively autoregulating its own transcription. ThehslJgene was found to be negatively regulated by CysB and directly correlated with novobiocin resistance of the bacterium.cysBmutants showed upregulation of thehslJ : : lacZgene fusion and exhibited increased novobiocin resistance. In this study thehslJtranscription start point and the corresponding putativeσ70promoter were determined. ThehslJpromoter region was defined by employing differenthslJ–lacZoperon fusions, and transcription of thehslJgene was shown to be subject to both repression imposed by the CysB regulator and direct or indirect autogenous negative control. These two regulations compete to some extent but they are not mutually exclusive. CysB acts as a direct repressor ofhslJtranscription and binds thehslJpromoter region that carries the putative CysB repressor site. This CysB binding, apparently responsible for repression, is enhanced in the presence of the ligandN-acetylserine (NAS), hitherto considered to be a positive cofactor in CysB-mediated gene regulations. Interallelic complementation of characterized CysB mutants I33N and S277Ter partially restored the repression ofhslJtranscription and the consequent novobiocin sensitivity, but did not complement the cysteine auxotrophy.

Identification of the CysB-regulated gene, hslJ, related to the Escherichia coli novobiocin resistance phenotype

The cysB gene product is a LysR-type regulatory protein required for expression of the cys regulon. cysB mutants of Escherichia coli and Salmonella, along with being auxotrophs for the cysteine, exhibit increased resistance to the antibiotics novobiocin (Nov) and mecillinam. In this work, by using lambdaplacMu9 insertions creating random lacZ fusions, we identify a gene, hslJ, whose expression appeared to be increased in cysB mutants and needed for Nov resistance. Measurements of the HSLJ::lacZ gene fusion expression demonstrated that the hslJ gene is negatively regulated by CysB. In addition we observe the negative autogenous control of HslJ. When the control imposed by CysB is lifted in the cysB mutant, the elevation of Nov resistance can be achieved only in the presence of wild-type hslJ allele. A double cysB hslJ mutant restores the sensitivity to Nov. Overexpression of the wild-type HslJ protein either in a cysB(+) or a cysB(-) background increases the level of Nov resistance indicating that hslJ product is indeed involved in accomplishing this phenotype. The HSLJ::OmegaKan allele encodes the C-terminaly truncated mutant protein HslJ Q121Ter which is not functional in achieving the Nov resistance but when overexpressed induces the psp operon. Finally, we found that inactivation of hslJ does not affect the increased resistance to mecillinam in cysB mutants.

[Work capacity evaluation in workers with arterial hypertension]

The aim of this study was to show the results of working ability estimation of the workers with arterial hypertension. The estimation included 313 workers with arterial hypertension estimated by Disability Commission during 1999. Arterial hypertension was a leading diagnosis in 30.9% cause of working ability estimation. The majority of workers belonged to the 41-60 years age group and were with arterial hypertension with complications on the fundus and on the heart. In the examined group the majority of workers was declared as first category invalid (35.8%), while 32.3% of hypertensive workers had to change the working place. The majority of the first category invalids were among the hypertensive workers from textile and chemical industry, as well as among the professional drivers. The changing of the working place was more frequently suggested to the workers in textile and metal industry and in printing firms. These results could be explained by the influence of professional noxious agents on the onset and development of arterial hypertension.

The Serbian version of the Childhood Health Assessment Questionnaire (CHAQ) and the Child Health Questionnaire (CHQ)

We report herein the results of the cross-cultural adaptation and validation into the Serbian language of the parentís version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Serbian CHAQ-CHQ were fully validated with 3 forward and 1 backward translations. A total of 139 subjects were enrolled: 79 patients with JIA (30% systemic onset, 28% polyarticular onset, 6% extended oligoarticular subtype, and 36% persistent oligoarticular subtype) and 60 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the systemic, polyarticular and extended oligoarticular subtypes having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, polyarticular onset and extended oligoarticular subtypes having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Serbian version of the CHAQ-CHQ is a reliable, and valid tool for the functional, physical and psychosocial assessment of children with JIA.

Glycoprotein identification and localization of O-glycosylation sites by mass spectrometric analysis of deglycosylated/alkylaminylated peptide fragments

In-gel digestion of densely O-glycosylated proteins, an essential step in proteome analysis, is often hampered by steric hindrance of the proteases. To overcome this technical problem a simple and convenient method has been developed, which combines several advantages: (1) Approximately 70% of the oligosaccharides are cleaved without significant protein hydrolysis at the optimal reaction conditions of 70% ethylamine, and quantitative cleavage is achieved with 40% methylamine, at 50 degrees C. (2) To the unsaturated derivatives of Ser and Thr the alkylamine is added as a label of previous O-glycosylation sites. (3) The alkylaminylated protein is effectively cleaved by proteolysis. (4) The modified peptides are identified by MALDI mass spectrometry under consideration of incremental mass increases. (5) The alkylamine label is stable under MALDI post-source-decay analysis as well as in collision-induced dissociation experiments allowing sequencing and peptide localization of O-glycosylation sites. Applicability of the method is evaluated with a series of synthetic glycopeptides, the densely O-glycosylated human glycophorin A, and with the mucin MUC1 from human milk fat globule membranes.

Occupational risk of tuberculosis among health care workers at the Institute for Pulmonary Diseases of Serbia

SETTING

The Institute for Pulmonary Diseases of Serbia, which specialises in diagnosis and treatment of lung diseases in a region with approximately 550-600 TB admissions per year.

OBJECTIVE

To assess the occupational risk of tuberculosis (TB) among health care workers (HCWs) employed at this institution.

DESIGN

Retrospective analysis of morbidity of TB among HCWs over a 12-year period (1986-1997). The incidence of TB among HCWs was estimated by the frequency of bacteriologically or histologically confirmed active disease. All HCWs at our institution underwent routine pre-employment screening, consisting of verification of BCG vaccination, PPD tuberculin reactivity, chest X-ray and laboratory evaluation.

RESULTS

Of an average 267 employed HCWs, pulmonary TB occurred in nine (six nurses and three laboratory technicians). Cumulative incidence for HCWs was 3451/100,000, compared to 454/100,000 in the general population, for an incidence rate ratio of 7.6.

CONCLUSION

The risk of TB among HCWs employed at the Institute for Pulmonary Diseases of Serbia in Belgrade is 7.6 times higher than that observed in the general population, suggesting occupational acquisition of TB.