MAGNETIC FORCES IN ORTHODONTICS

BACKGROUND: Pneumococcus is a major human pathogen and the polysaccharide capsule is considered its main virulence factor. Nevertheless, strains lacking a capsule, named non-typeable pneumococcus (NT), are maintained in nature and frequently colonise the human nasopharynx. Interest in these strains, not targeted by any of the currently available pneumococcal vaccines, has been rising as they seem to play an important role in the evolution of the species. Currently, there is a paucity of data regarding this group of pneumococci. Also, questions have been raised on whether they are true pneumococci. We aimed to obtain insights in the genetic content of NT and the mechanisms leading to non-typeability and to genetic diversity. RESULTS: A collection of 52 NT isolates representative of the lineages circulating in Portugal between 1997 and 2007, as determined by pulsed-field gel electrophoresis and multilocus sequence typing, was analysed. The capsular region was sequenced and comparative genomic hybridisation (CGH) using a microarray covering the genome of 10 pneumococcal strains was carried out. The presence of mobile elements was investigated as source of intraclonal variation. NT circulating in Portugal were found to have similar capsular regions, of cps type NCC2, i.e., having aliB-like ORF1 and aliB-like ORF2 genes. The core genome of NT was essentially similar to that of encapsulated strains. Also, competence genes and most virulence genes were present. The few virulence genes absent in all NT were the capsular genes, type-I and type-II pili, choline-binding protein A (cbpA/pspC), and pneumococcal surface protein A (pspA). Intraclonal variation could not be entirely explained by the presence of prophages and other mobile elements. CONCLUSIONS: NT circulating in Portugal are a homogeneous group belonging to cps type NCC2. Our observations support the theory that they are bona-fide pneumococcal isolates that do not express the capsule but are otherwise essentially similar to encapsulated pneumococci. Thus we propose that NT should be routinely identified and reported in surveillance studies

Fertility and body composition after laparoscopic bilateral adrenalectomy in a 30-year-old female with congenital adrenal hyperplasia

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is caused by an inborn defect in the 21-hydroxylase gene (CYP21), leading to virilization of female patients and causing ambiguous genitals in the majority of female infants. Adult women may suffer from loss of libido, irregular or absent cycles, and reduced fertility, despite intensive medical treatment. These problems have stimulated the search for alternative treatment modalities. We present an adult female patient, who was difficult to treat medically and whose clinical situation markedly improved after laparoscopic bilateral adrenalectomy. The procedure was well tolerated and without side effects. Postoperatively the elevated serum progesterone and 17-hydroxyprogesterone levels, as well as the undetectable LH levels, normalized. The procedure resulted in marked clinical improvement. Within 12 months after surgery she lost 11 kg in weight. This weight loss consisted mainly of adipose tissue. Acne disappeared, and she had a regular 4-week menstrual cycle, with progesterone levels that are compatible with a luteal phase. The introduction of laparoscopic techniques may give an impulse to the application of surgical therapy at a larger scale in patients with 21-hydroxylase deficiency who are difficult to treat with adrenal suppression therapy

Identification of conditionally essential genes for Streptococcus suis infection in pigs

Streptococcus suis is a Gram-positive bacterium and zoonotic pathogen that causes meningitis and sepsis in pigs and humans. The aim of this study was to identify genes required for S. suis infection. We created Tn-Seq libraries in a virulent S. suis strain 10, which was used to inoculate pigs in an intrathecal experimental infection. Comparative analysis of the relative abundance of mutants recovered from different sites of infection (blood, cerebrospinal fluid, and meninges of the brain) identified 361 conditionally essential genes, i.e. required for infection, which is about 18% of the genome. The conditionally essential genes were primarily involved in metabolic and transport processes, regulation, ribosomal structure and biogenesis, transcription, and cell wall membrane and envelope biogenesis, stress defenses, and immune evasion. Directed mutants were created in a set of 10 genes of different genetic ontologies and their role was determined in ex vivo models. Mutants showed different levels of sensitivity to survival in whole blood, serum, cerebrospinal fluid, thermic shock, and stress conditions, as compared to the wild type. Additionally, the role of three selected mutants was validated in co-infection experiments in which pigs were infected with both wild type and isogenic mutant strains. The genetic determinants of infection identified in this work contribute to novel insights in S. suis pathogenesis and could serve as targets for novel vaccines or antimicrobial drugs

From microbial gene essentiality to novel antimicrobial drug targets

Background: Bacterial respiratory tract infections, mainly caused by Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are among the leading causes of global mortality and morbidity. Increased resistance of these pathogens to existing antibiotics necessitates the search for novel targets to develop potent antimicrobials. Result: Here, we report a proof of concept study for the reliable identification of potential drug targets in these human respiratory pathogens by combining high-density transposon mutagenesis, high-throughput sequencing, and integrative genomics. Approximately 20% of all genes in these three species were essential for growth and viability, including 128 essential and conserved genes, part of 47 metabolic pathways. By comparing these essential genes to the human genome, and a database of genes from commensal human gut microbiota, we identified and excluded potential drug targets in respiratory tract pathogens that will have off-target effects in the host, or disrupt the natural host microbiota. We propose 249 potential drug targets, 67 of which are targets for 75 FDA-approved antimicrobials and 35 other researched small molecule inhibitors. Two out of four selected novel targets were experimentally validated, proofing the concept. Conclusion: Here we have pioneered an attempt in systematically combining the power of high-density transposon mutagenesis, high-throughput sequencing, and integrative genomics to discover potential drug targets at genome-scale. By circumventing the time-consuming and expensive laboratory screens traditionally used to select potential drug targets, our approach provides an attractive alternative that could accelerate the much needed discovery of novel antimicrobials

XAB2, a novel tetratricopeptide repeat protein, involved in transcription-coupled repair and transcription.

Nucleotide excision repair is a highly versatile DNA repair system responsible for elimination of a wide variety of lesions from the genome. It is comprised of two subpathways: transcription-coupled repair that accomplishes efficient removal of damage blocking transcription and global genome repair. Recently, the basic mechanism of global genome repair has emerged from biochemical studies. However, little is known about transcription-coupled repair in eukaryotes. Here we report the identification of a novel protein designated XAB2 (XPA-binding protein 2) that was identified by virtue of its ability to interact with XPA, a factor central to both nucleotide excision repair subpathways. The XAB2 protein of 855 amino acids consists mainly of 15 tetratricopeptide repeats. In addition to interacting with XPA, immunoprecipitation experiments demonstrated that a fraction of XAB2 is able to interact with the transcription-coupled repair-specific proteins CSA and CSB as well as RNA polymerase II. Furthermore, antibodies against XAB2 inhibited both transcription-coupled repair and transcription in vivo but not global genome repair when microinjected into living fibroblasts. These results indicate that XAB2 is a novel component involved in transcription-coupled repair and transcription

Dutch Oncology COVID-19 consortium:Outcome of COVID-19 in patients with cancer in a nationwide cohort study

Aim of the study: Patients with cancer might have an increased risk for severe outcome of coronavirus disease 2019 (COVID-19). To identify risk factors associated with a worse outcome of COVID-19, a nationwide registry was developed for patients with cancer and COVID-19. Methods: This observational cohort study has been designed as a quality of care registry and is executed by the Dutch Oncology COVID-19 Consortium (DOCC), a nationwide collaboration of oncology physicians in the Netherlands. A questionnaire has been developed to collect pseudonymised patient data on patients' characteristics, cancer diagnosis and treatment. All patients with COVID-19 and a cancer diagnosis or treatment in the past 5 years are eligible. Results: Between March 27th and May 4th, 442 patients were registered. For this first analysis, 351 patients were included of whom 114 patients died. In multivariable analyses, age ≥65 years (p < 0.001), male gender (p = 0.035), prior or other malignancy (p = 0.045) and active diagnosis of haematological malignancy (p = 0.046) or lung cancer (p = 0.003) were independent risk factors for a fatal outcome of COVID-19. In a subgroup analysis of patients with active malignancy, the risk for a fatal outcome was mainly determined by tumour type (haematological malignancy or lung cancer) and age (≥65 years). Conclusion: The findings in this registry indicate that patients with a haematological malignancy or lung cancer have an increased risk of a worse outcome of COVID-19. During the ongoing COVID-19 pandemic, these vulnerable patients should avoid exposure to severe acute respiratory syndrome coronavirus 2, whereas treatment adjustments and prioritising vaccination, when available, should also be considered

Joint sequencing of human and pathogen genomes reveals the genetics of pneumococcal meningitis

Streptococcus pneumoniae is a common nasopharyngeal colonizer, but can also cause lifethreatening invasive diseases such as empyema, bacteremia and meningitis. Genetic variation of host and pathogen is known to play a role in invasive pneumococcal disease, though to what extent is unknown. In a genome-wide association study of human and pathogen we show that human variation explains almost half of variation in susceptibility to pneumococcal meningitis and one-third of variation in severity, identifying variants in CCDC33 associated with susceptibility. Pneumococcal genetic variation explains a large amount of invasive potential (70%), but has no effect on severity. Serotype alone is insufficient to explain invasiveness, suggesting other pneumococcal factors are involved in progression to invasive disease. We identify pneumococcal genes involved

Species- and strain-specific control of a complex, flexible regulon by Bordetella BvgAS.

Contains fulltext : 50136.pdf (publisher's version ) (Open Access)The Bordetella master virulence regulatory system, BvgAS, controls a spectrum of gene expression states, including the virulent Bvg(+) phase, the avirulent Bvg(-) phase, and at least one Bvg-intermediate (Bvg(i)) phase. We set out to define the species- and strain-specific features of this regulon based on global gene expression profiling. Rather than functioning as a switch, Bvg controls a remarkable continuum of gene expression states, with hundreds of genes maximally expressed in intermediate phases between the Bvg(+) and Bvg(-) poles. Comparative analysis of Bvg regulation in B. pertussis and B. bronchiseptica revealed a relatively conserved Bvg(+) phase transcriptional program and identified previously uncharacterized candidate virulence factors. In contrast, control of Bvg(-)- and Bvg(i)-phase genes diverged substantially between species; regulation of metabolic, transporter, and motility loci indicated an increased capacity in B. bronchiseptica, compared to B. pertussis, for ex vivo adaptation. Strain comparisons also demonstrated variation in gene expression patterns within species. Among the genes with the greatest variability in patterns of expression, predicted promoter sequences were nearly identical. Our data suggest that the complement of transcriptional regulators is largely responsible for transcriptional diversity. In support of this hypothesis, many putative transcriptional regulators that were Bvg regulated in B. bronchiseptica were deleted, inactivated, or unregulated by BvgAS in B. pertussis. We propose the concept of a "flexible regulon." This flexible regulon may prove to be important for pathogen evolution and the diversification of host range specificity

Characterization of the molecular interplay between Moraxella catarrhalis and human respiratory tract epithelial cells

Contains fulltext : 183574.PDF (publisher's version ) (Open Access)Moraxella catarrhalis is a mucosal pathogen that causes childhood otitis media and exacerbations of chronic obstructive pulmonary disease in adults. During the course of infection, M. catarrhalis needs to adhere to epithelial cells of different host niches such as the nasopharynx and lungs, and consequently, efficient adhesion to epithelial cells is considered an important virulence trait of M. catarrhalis. By using Tn-seq, a genome-wide negative selection screenings technology, we identified 15 genes potentially required for adherence of M. catarrhalis BBH18 to pharyngeal epithelial Detroit 562 and lung epithelial A549 cells. Validation with directed deletion mutants confirmed the importance of aroA (3-phosphoshikimate 1-carboxyvinyl-transferase), ecnAB (entericidin EcnAB), lgt1 (glucosyltransferase), and MCR_1483 (outer membrane lipoprotein) for cellular adherence, with DeltaMCR_1483 being most severely attenuated in adherence to both cell lines. Expression profiling of M. catarrhalis BBH18 during adherence to Detroit 562 cells showed increased expression of 34 genes in cell-attached versus planktonic bacteria, among which ABC transporters for molybdate and sulfate, while reduced expression of 16 genes was observed. Notably, neither the newly identified genes affecting adhesion nor known adhesion genes were differentially expressed during adhesion, but appeared to be constitutively expressed at a high level. Profiling of the transcriptional response of Detroit 562 cells upon adherence of M. catarrhalis BBH18 showed induction of a panel of pro-inflammatory genes as well as genes involved in the prevention of damage of the epithelial barrier. In conclusion, this study provides new insight into the molecular interplay between M. catarrhalis and host epithelial cells during the process of adherence