Iron Acquisition Mechanisms and Their Role in the Virulence of Burkholderia Species

Burkholderia is a genus within the β-Proteobacteriaceae that contains at least 90 validly named species which can be found in a diverse range of environments. A number of pathogenic species occur within the genus. These include Burkholderia cenocepacia and Burkholderia multivorans, opportunistic pathogens that can infect the lungs of patients with cystic fibrosis, and are members of the Burkholderia cepacia complex (Bcc). Burkholderia pseudomallei is also an opportunistic pathogen, but in contrast to Bcc species it causes the tropical human disease melioidosis, while its close relative Burkholderia mallei is the causative agent of glanders in horses. For these pathogens to survive within a host and cause disease they must be able to acquire iron. This chemical element is essential for nearly all living organisms due to its important role in many enzymes and metabolic processes. In the mammalian host, the amount of accessible free iron is negligible due to the low solubility of the metal ion in its higher oxidation state and the tight binding of this element by host proteins such as ferritin and lactoferrin. As with other pathogenic bacteria, Burkholderia species have evolved an array of iron acquisition mechanisms with which to capture iron from the host environment. These mechanisms include the production and utilization of siderophores and the possession of a haem uptake system. Here, we summarize the known mechanisms of iron acquisition in pathogenic Burkholderia species and discuss the evidence for their importance in the context of virulence and the establishment of infection in the host. We have also carried out an extensive bioinformatic analysis to identify which siderophores are produced by each Burkholderia species that is pathogenic to humans

Serum anti-Müllerian hormone as a predictor of polycystic ovarian syndrome among women of reproductive age

BackgroundPolycystic ovarian syndrome (PCOS) affects up to one-fifth of women of reproductive age and causes anovulatory subfertility. Some studies have recommended that an anti-Müllerian hormone (AMH) level greater than 3.8–5 ng/mL can be used for diagnosing PCOS. This study aims to analyse serum AMH levels among PCOS women of reproductive age to use AMH as a biomarker predictor along with other Rotterdam criteria.MethodsIn this cross-sectional study, a total of 98 women visiting the fertility center of a private hospital in Lahore, Pakistan, were screened. Data were obtained from 51 PCOS newly diagnosed women aged 28.24 years (SD ± 4.84 years) meeting at least two of the Rotterdam criteria and specific inclusion criteria. Baseline variables, menstrual cycle length, ovarian morphology on ultrasound, hirsutism, sex hormones, gonadotropin, and serum AMH levels were analysed during the follicular phase (1–5 days) of the menstrual cycle. Serum AMH was measured by an enzyme-linked immunosorbent assay.ResultsA high serum AMH level (7.23 ± 4.67 ng/ml) was recorded with normal sex hormone levels. Women with oligo-/amenorrhea had a significant mean difference for luteinizing hormone (p = 0.02) and AMH levels (p = 0.03) when compared with women of normal menstrual cycle length. PCOS women with high AMH levels (≥ 3.9 ng/ml) showed a significant difference in ovarian morphology (p < 0.05) when compared with the normal AMH group.ConclusionsAn elevated serum AMH level can be used as a strong predictor to reflect the certainty of PCOS diagnosis among women of reproductive age when study concurrently with the other Rotterdam criteria

Comparison of physical activity levels and dietary habits between women with polycystic ovarian syndrome and healthy controls of reproductive age: A case-control study

BackgroundPolycystic ovarian syndrome (PCOS) is a reproductive hormonal anomaly prevalent among women of reproductive age, with an alarmingly high prevalence of 52% among Pakistani women. This study aims to compare the daily physical activity and dietary habits of women with PCOS with age-matched healthy controls living in Lahore, Pakistan.MethodsA case–control study design was used to collect data from a private hospital situated in Lahore, Pakistan. Data was collected from 115 participants of reproductive age (18–45 years) using a researcher-administered questionnaire. Demographic variables, reproductive characteristics, anthropometric measurements, and seven days of physical activity levels using the international physical activity questionnaire (IPAQ-Short version) and seven days of dietary intake using the food frequency questionnaire (7 days-FFQ) were used to measure the dietary habits of the participants. Mosby’s Nutritac v4.0 software was used to estimate the macronutrients, vitamins, and minerals present in dietary intake. The glycaemic index and glycaemic load were calculated to compare the quality and quantity of carbohydrate consumption between the two groups.ResultsThe 49 PCOS cases, newly identified using the Rotterdam criteria, mean age 24.63 years (SD ± 4.76), and 66 healthy controls, mean age 23.24 years (SD ± 5.45), were compared. A significant difference (p ≤ 0.05) was found for reproductive characteristics, daily physical activity, and polyunsaturated fat and vitamin intake between the two groups. A binary logistic regression analysis showed that food with a low glycaemic index (GI ≤ 40) reduced the odds of PCOS occurrence by OR = 1.94. Similarly, food nutrients with a low glycaemic load (GL ≤ 10) can reduce PCOS occurrence by OR = 1.60.ConclusionThe daily physical activity levels and dietary habits of women of reproductive age can influence their reproductive characteristics and polycystic ovarian morphology. A diet with a low glycaemic load and index can produce beneficial reproductive health effects among women of reproductive age.<br/

Oral health perceptions and practices of caregivers at children’s religious schools and foster care centers: a qualitative exploratory study in Lahore, Pakistan

BackgroundOral diseases are one of the major public health problems worldwide and affect the population of all age groups. This qualitative study aimed to explore the perceptions and practices of caregivers at care centres and boarding religious schools responsible for managing children’s oral health.MethodsA qualitative ethnomethodological approach was used to collect data from the caregivers at the children’s religious schools and foster care centres. A purposive sampling technique was used to conduct focus group discussions comprising 4–7 caregivers from five foster care centres and religious schools located in Lahore, Pakistan.An interview guide was developed based on results from previous studies. An inductive approach was used to analyse data on broader oral health concepts to generate themes in this qualitative research. A three-step thematic analysis was applied to develop codes that were merged to generate categories and to conclude into themes from the transcribed data. Five focus group discussions were conducted at two foster care centres (FG1 &amp; FG2) and three religious schools (FG3, FG4 &amp; FG5). Foster care centres had children of both gender within the same premises; however, religious schools had segregated settings.ResultsThe following four themes emerged from the thematic analysis: development of the desired living environment and responsibilities of the caregivers, preexisting traditional personal knowledge of the caregivers determine children’s oral health, use of religio-cultural driven and convenience-based oral hygiene practices, and ethnomedicine, spiritual healing, and self-medication. Development and the existing living environment of the foster care centres and religious schools appeared important to manage the matters of the boarding children.ConclusionsThis qualitative study concludes that the oral health of the children at foster care centres and at religious schools depends upon the personal reasoning and pre-existing religio-cultural knowledge of the caregivers rather than on specialized oral health-oriented approaches. The foster care centres are more involved in supervising the children to maintain oral hygiene and oral health compared to religious schools.<br/

Distinct modes of promoter recognition by two iron starvation σ factors with overlapping promoter specificities

OrbS and PvdS are extracytoplasmic function (ECF) σ factors that regulate transcription of operons required for the biosynthesis of the siderophores ornibactin and pyoverdine in the B. cepacia complex and Pseudomonas spp., respectively. Here we show that promoter recognition by OrbS requires specific tetrameric -35 and -10 element sequences that are strikingly similar to those of the consensus PvdS-dependent promoter. However, whereas P. aeruginosa PvdS can serve OrbS-dependent promoters, OrbS cannot utilise PvdS-dependent promoters. To identify features present at OrbS-dependent promoters that facilitate recognition by OrbS, we carried out a detailed analysis of the nucleotide sequence requirements for promoter recognition by both OrbS and PvdS. This revealed that DNA sequence features located outside of the sigma binding elements are required for efficient promoter utilisation by OrbS. In particular, the presence of an A-tract extending downstream from the -35 element at OrbS-dependent promoters was shown to be an important contributor to OrbS specificity. Our observations demonstrate that the nature of the spacer sequence can have a major impact on promoter recognition by some ECF sigma factors through modulation of the local DNA architecture

Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters