Jacyara Maria Brito Macedo

Complete genome sequence of the sugarcane nitrogen-fixing endophyte Gluconacetobacter diazotrophicus Pal5

BackgroundGluconacetobacter diazotrophicus Pal5 is an endophytic diazotrophic bacterium that lives in association with sugarcane plants. It has important biotechnological features such as nitrogen fixation, plant growth promotion, sugar metabolism pathways, secretion of organic acids, synthesis of auxin and the occurrence of bacteriocins.ResultsGluconacetobacter diazotrophicus Pal5 is the third diazotrophic endophytic bacterium to be completely sequenced. Its genome is composed of a 3.9 Mb chromosome and 2 plasmids of 16.6 and 38.8 kb, respectively. We annotated 3,938 coding sequences which reveal several characteristics related to the endophytic lifestyle such as nitrogen fixation, plant growth promotion, sugar metabolism, transport systems, synthesis of auxin and the occurrence of bacteriocins. Genomic analysis identified a core component of 894 genes shared with phylogenetically related bacteria. Gene clusters for gum-like polysaccharide biosynthesis, tad pilus, quorum sensing, for modulation of plant growth by indole acetic acid and mechanisms involved in tolerance to acidic conditions were identified and may be related to the sugarcane endophytic and plant-growth promoting traits of G. diazotrophicus. An accessory component of at least 851 genes distributed in genome islands was identified, and was most likely acquired by horizontal gene transfer. This portion of the genome has likely contributed to adaptation to the plant habitat.ConclusionThe genome data offer an important resource of information that can be used to manipulate plant/bacterium interactions with the aim of improving sugarcane crop production and other biotechnological applications.

Is higher prevalence of cervical intraepithelial neoplasia in women with lupus due to immunosuppression

Background:Cervical cancer (CC) is still the second in prevalence and mortality among women. In spite of previously observed higher incidence of cervical dysplasia among systemic lupus erythematosus (SLE) patients, few studies have considered the influence of classic risk factors and the use of immunosuppressors (IM). Objectives:To study cervical dysplasia prevalence among SLE patients submitted or not to immunosuppression and to evaluate its association with classic risk factors. Methods:A group of 171 SLE patients including 87 who were receiving IM continuously for at least 1 year was compared with 222 age- and sociocultural-paired women (control group) submitted to routine cervical cytopathology. Statistical methods included univariate and multivariate analysis, besides parametric and nonparametric tests. Results:The prevalence of atypical squamous cells of undetermined significance, low-grade and high-grade intraepithelial lesions were significantly increased in SLE patients (12.8%, 5.8%, and 3.5%, respectively) compared with controls (3.1%, 0.9%, and none, respectively, P = 0.0001), although they presented significantly fewer classic risk factors for CC. Multivariate analysis showed that SLE women had a 7-fold higher prevalence of cervical dysplasia (OR: 7.23, 95% IC: 3.40–15.38) and an 11-fold higher prevalence of premalignant cervical dysplasia (OR: 11.36, 95% IC: 2.57–50.10) compared with controls. SLE patients with long-term use of IM presented even higher prevalence of low-grade and high-grade intraepithelial lesions in comparison with those without long-term use of these agents (68.7% vs. 31.1%, P = 0.03). Conclusions:This study provides evidence that even though not presenting the classic risk factors for CC, SLE patients, especially those exposed to long-term immunosuppression, have increased chances of presenting more premalignant lesions than the general population and they probably need to follow a more stringent CC prevention program.

Detection of cytotoxin genotypes of Helicobacter pylori in stomach, saliva and dental plaque

BACKGROUND The aim of this study was to detect the presence of Helicobacter pylori and its virulent cagA genes in the oral cavity of individuals with upper gastric diseases. Sixty-two individuals (42+/-2.3 years) with dispepsy symptoms, referred for gastroscopy and who were H. pylori positive in the gastric biopsy, were recruited and separated in two groups: case group-individuals with gastric disease (n = 30); control group-individuals with no gastric disease (n = 32); saliva, dental plaque and biopsy samples were collected from all individuals. Oral and biopsy samples were analyzed by PCR using specific primers for H. pylori 16S ribosomal and cagA genes. PCR products were sequenced for DNA homology confirmation. H. pylori was detected neither in dental plaque nor in saliva in the control group. In the case group H. pylori DNA was detected in 16/30 (53.3%) saliva samples and in 11/30 (36.6%) dental plaque samples. The cagA gene was detected in 13/30 (43.3%) gastric biopsies, in 7/16 (43.8%) saliva samples, and in 3/11 (27.3%) dental plaque samples. Eighteen (60.0%) individuals in the case group were H. pylori positive both in oral and biopsy samples, and 8 (26.6%) of those were positive for cagA-H. pylori DNA. H. pylori and its virulent clone showed a higher prevalence in the oral cavity of individuals in the case group than in the control group (p < 0.05). Our results suggest that dental plaque and saliva may serve as temporary reservoir for H. pylori and its virulent cagA variant in individuals with gastric disease.

Presence of Helicobacter pylori in supragingival dental plaque of individuals with periodontal disease and upper gastric diseases

BACKGROUND Helicobacter pylori is a Gram-negative microorganism which is able to colonize the gastric mucosa and is associated with peptic ulcer, gastric carcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Several studies have detected this bacterium in the oral cavity, suggesting it as a potential reservoir. The aim of this study was to investigate the presence of H. pylori in the oral cavity of individuals with periodontal disease and gastric diseases. METHODS 115 individuals, with mean age 49.6 (±5.8) years, were divided in 4 groups: (A) with gastric diseases and periodontal disease; (B) with gastric diseases and no periodontal disease; (C) without gastric diseases and without periodontal disease, (D) without gastric diseases and with periodontal disease. Supra and subgingival plaque samples were collected from posterior teeth of the individuals with sterile paper points, and prepared for Polymerase Chain Reaction analysis. Fishers exact test was used for detecting statistical differences between groups (p<0.05). RESULTS H. pylori was detected in supragingival plaque of 9/36 (25%) of group A, 1/31 (0.3%) of group B, 0 (0%) of group C and 3/36 (8.3%) of group D. No subgingival samples were positive for H. pylori. There was a statistically higher prevalence of H. pylori in groups A and D when compared to B and C (p<0.05). CONCLUSION H. pylori was detected in the supragingival plaque, but not in the subgingival plaque, of individuals with periodontal disease and upper gastric diseases. There was an association between the supragingival colonization of H. pylori and oral hygiene parameters such as the presence of plaque and gingival bleeding.

Lower expression of p14ARF and p16INK4a correlates with higher DNMT3B expression in human oesophageal squamous cell carcinomas

Oesophageal squamous cell carcinoma (ESCC) is one of the most common malignancies and is the sixth cause of cancer-related death in the world. Inactivation of cell-cycle regulating genes, such as p14ARF and p16INK4a, and cell adhesion genes, such as E-cadherin, is common in cancer, and results from genetic and/or epigenetic alterations. Therefore, we have analysed the mRNA expression of p14ARF, p16INK4a and E-cadherin in 17 matched ESCC and normal mucosal samples obtained from Brazilian patients by semi-quantitative RT-PCR. The expression of p14ARF and p16INK4a was absent or reduced in several ESCC samples. Hypermethylation of CpG islands, caused by the action of DNA methyltransferases (DNMTs), is a major form of epigenetic inactivation of the p14ARF and p16INK4a genes in tumours. Hence, we also investigated the mRNA expression of the human DNA methyltransferases in normal oesophageal mucosa and in the tumour matched samples. All DNMTs were constitutively expressed in the normal oesophageal mucosa but a significantly higher expression of DNMT3B was observed in the tumours. Data analysis by the Spearman rank test showed that the expression of DNMT3B was inversely correlated with that of p14ARF and p16INK4a. Our results suggest that DNMT3B over-expression may be involved in the suppression or lower expression of p14ARF and p16INK4a observed in ESCC.

Immunohistochemical expression of cyclin D1, p16Ink4a, p21WAF1, and Ki-67 correlates with the severity of cervical neoplasia.

High-risk human papillomaviruses are closely associated with cervical cancer and its precursor lesions through interactions between the E6 and E7 oncoproteins and the cell-cycle regulatory proteins, such as p53 and pRb, respectively. As other molecules involved in the cell-cycle control seem to be important for human papillomavirus (HPV)-mediated cervical carcinogenesis, we have analyzed the expression of p53, p21, p16, cyclin D1, and Ki-67 and the presence of HPV (HPV pool and HPV-16) by immunohistochemical studies using tissue microarray in low squamous intraepithelial lesions (n=50), high squamous intraepithelial lesions (n=98), and cervical carcinoma (n=18). We have found a significant increase in the expression of p16 and p21 (P<0.001) from low- to high-grade lesions and cancer. In contrast, cyclin D1 expression showed a significant decrease in more severe lesions (P<0.001). p16, Ki-67, p21, and p53 positivity increased with the cell-layer level and the lesion severity, with stronger correlations being observed for p16 and Ki-67. High positivity for HPV pool (96.3%) and HPV-16 (77.5%) immunostaining was detected in all cases, with an association between p16 and cyclin D1 expression and HPV-16 infection. Our tissue microarray results corroborate the usefulness of the immunohistochemical assessment of cell-cycle biomarkers in distinguishing different groups of precursor lesions of the cervix and cervical carcinoma.

Higher levels of salivary MUC5B and MUC7 in individuals with gastric diseases who harbor Helicobacter pylori

OBJECTIVE The aim of the present study was to assess the salivary levels of MUC5B and MUC7 in individuals with dyspeptic disease and Helicobacter pylori (H. pylori) in the stomach, compared to individuals without dyspeptic disease. METHODS 30 individuals with dyspeptic disease, who underwent endoscopy for upper gastrointestinal complaints at Hospital Pedro Ernesto-RJ, Brasil and tested positive for H. pylori, and 23 controls with no dyspeptic disease, with mean age 53.5+/-4.4 years, were included in the study. Saliva samples and 3 antral biopsy were taken for PCR analysis and histologic examination. In addition, saliva samples were tested by ELISA with F2 monoclonal antibody and EU7A antibody against MUC7, to determine MUC5B and MUC7 levels, prior to endoscopic examination. The expression pattern of the proteins was quantified by comparison to a pooled saliva sample of 19 healthy volunteers. RESULTS MUC5B and MUC7 salivary levels were higher in the individuals with dyspeptic disease than in controls (p<0.0001). 33.3% (9/30) of the dyspeptic individuals and 0% of the controls had H. pylori in the oral cavity. CONCLUSIONS Individuals with gastric diseases, with H. pylori in the stomach, showed higher levels of salivary H. pylori receptors-MUC5B and MUC7-than individuals without gastric diseases. These results suggest that higher levels of specific salivary mucins could be useful as risk indicators for infection by H. pylori.

Lignin peroxidase isoforms from Streptomyces viridosporus T7A: are they a monomer based structure?

Five fractions with lignin peroxidase activity were isolated by FPLC-Mono Q from a Streptomyces viridosporus culture. F4 and F5 showed the highest specific activity and degree of protein homogeneity by chromatofocusing, IEF- and gradient-PAGE. The individual analysis of F4 and F5 by FPLC-Superdex 75, showed MW that were multiples to each other (68,000; 23,000; 12,000), although by SDS PAGE a sole MW of 13,500 was obtained, indicating a monomer based structure. The amino-acid composition of F5 showed absence of sulfur amino acids.

Effects of MDM2 promoter polymorphisms on the development of cervical neoplasia in a Southeastern Brazilian population.

Abstract We investigated the importance of two adjacent functional polymorphisms in the Murine Double Minute 2 (MDM2) gene, SNP285 G > C and SNP309 T > G, for the development of cervical lesions in a Southeastern Brazilian population (293 cases and 184 controls). MDM2 genotyping was performed by PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) and/or DNA sequencing. MDM2 SNP309 has potential as a biomarker of cervical neoplasia in non-smokers, patients with family history of cancer, or those who had late sexual debut (>16 years). Besides, this polymorphism may help identify women at risk of developing severe cervical lesion at a young age (<30 years).

Association of CDKN2A polymorphisms with the severity of cervical neoplasia in a Brazilian population

Abstract Variants of p16(INK4a) and p14(ARF), encoded by the CDKN2A locus, may respond differently to the presence of human papillomavirus (HPV). We investigated the potential association of two CDKN2A polymorphisms, 500C > G (rs11515) and 540C > T (rs3088440), with cervical neoplasia in patients with cervical lesions and healthy controls (n = 492). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), single-strand conformation polymorphism (SSCP) and/or DNA sequencing techniques were employed for genotyping. The 500G allele was found higher, whereas the 540T/T genotype was less frequent in patients with more severe lesions. The CDKN2A variants may have the potential to be markers for the management of patients with cervical neoplasia.