Validation and calibration of a novel GEM biosensor for specific detection of Cd2+, Zn2+, and Pb2.

BACKGROUND: In this study, we designed a novel genetic circuit sensitive to Cd2+, Zn2+ and Pb2+ by mimicking the CadA/CadR operon system mediated heavy metal homeostasis mechanism of Pseudomonas aeruginosa. The regular DNA motifs on natural operon were reconfigured and coupled with the enhanced Green Fluorescent Protein (eGFP) reporter to develop a novel basic NOT type logic gate CadA/CadR-eGFP to respond metal ions mentioned above. A Genetically Engineered Microbial (GEM)-based biosensor (E.coli-BL21:pJET1.2-CadA/CadR-eGFP) was developed by cloning the chemically synthesised CadA/CadR-eGFP gene circuit into pJET1.2-plasmid and transforming into Escherichia coli (E. coli)-BL21 bacterial cells. RESULTS: The GEM-based biosensor cells indicated the reporter gene expression in the presence of Cd2+, Zn2+ and Pb2+ either singly or in combination. Further, the same biosensor cells calibrated for fluorescent intensity against heavy metal concentration generated linear graphs for Cd2+, Zn2+ and Pb2+ with the R2 values of 0.9809, 0.9761 and 0.9758, respectively as compared to non-specific metals, Fe3+ (0.0373), AsO43- (0.3825) and Ni2+ (0.8498) making our biosensor suitable for the detection of low concentration of the former metal ions in the range of 1-6 ppb. Furthermore, the GEM based biosensor cells were growing naturally within the concentration range of heavy metals, at 37 °C and optimum pH = 7.0 in the medium, resembling the characteristics of wildtype E.coli. CONCLUSION: Finally, the novel GEM based biosensor cells developed in this study can be applied for detection of targeted heavy metals in low concentration ranges (1-6 ppb) at normal bacterial physiological conditions.

Mass Transport via In-Plane Nanopores in Graphene Oxide Membranes.

Angstrom-confined solvents in 2D laminates can travel through interlayer spacings, through gaps between adjacent sheets, and via in-plane pores. Among these, experimental access to investigate the mass transport through in-plane pores is lacking. Our experiments allow an understanding of this mass transport via the controlled variation of oxygen functionalities, size and density of in-plane pores in graphene oxide membranes. Contrary to expectations, our transport experiments show that higher in-plane pore densities may not necessarily lead to higher water permeability. We observed that membranes with a high in-plane pore density but a low amount of oxygen functionalities exhibit a complete blockage of water. However, when water-ethanol mixtures with a weaker hydrogen network are used, these membranes show an enhanced permeation. Our combined experimental and computational results suggest that the transport mechanism is governed by the attraction of the solvents toward the pores with functional groups and hindered by the strong hydrogen network of water formed under angstrom confinement.

Nutritional status and dietary intake of the population aged 1-60 years during the COVID-19 Pandemic in Sri Lanka.

Background: There is a co-existence of different forms of malnutrition leading to a Triple Burden of Malnutrition (TBM) in Sri Lanka. Accessing basic needs and services was a challenge during COVID-19 pandemic, which led to issues in food security with an effect on nutrition status of the population. Objectives: To estimate the prevalence of malnutrition and dietary intakes of the population aged 1 to 60 years. Methods: This study was conducted in 2021. A multistage cluster sample was drawn to represent households at national level using 75 clusters, and 24-hour dietary recalls were compared with estimated average requirements of different age groups. Height and weight of all selected participants were measured. Results: A total of 1776 households and 2991 individuals were studied. The prevalence of wasting, stunting and overweight of children aged 1-4 years (n=486) was 14%, 16.3% and 0.8% respectively. Thinness, stunting, overweight and obesity of children aged 5-9 years (n=388) was 21.4%, 8.5%, 5.2%, 5.1%; children aged 10-17 years (n=355) was 21.1%, 14.1%,11%, 8.2%; and adults aged 18-60 years (n=1762) was 9.9%, 5.4%, 32.6% and 11.5% respectively. Dietary intake gaps were minimal with energy and protein while it was wider with majority of vitamins, iron and calcium. Stunting of children aged 1-4 years was significantly associated with the low calcium and iron intakes. Conclusions: The presence of TBM amongst children and adults were observed with a dietary gap of essential micronutrients. This study highlights the need to re-orient the nutritional interventions to control TBM at population level.

ALDH1 immunoexpression in epithelial and stromal cells of oral lichen planus and lesions with lichenoid inflammatory infiltrate.

BACKGROUND: Oral Lichen Planus is a potential malignant disorder and shares clinical and histopathological features with other similar lesions. ALDH1 is a specific biomarker for stem cells identification, however its role in stromal cells of immune inflammatory infiltrate has not been explored. The aim of this study was to investigate the ALDH1 immunoexpression in epithelial and stromal cells of Oral Lichen Planus and other lesions with lichenoid inflammatory infiltrate. MATERIAL AND METHODS: 64 samples of Oral Lichen Planus, Oral Lichenoid Lesions, Oral Leukoplakia and Unspecific Chronic Inflammation were included. ALDH1 was evaluated in both epithelium and stromal cells. ALDH1+ cells ≥ 5% were considered positive in epithelium. Stromal cells were evaluated semi quantitatively. Fields were ranked in scores, according to criteria: 1 (0 to 10%); 2 (11 to 50%) and 3 (>50%). The mean value of the sum of the fields was the final score. Statistical differences among groups were investigated, considering p < 0.05. RESULTS: ALDH1 expression in epithelium was low in all groups without difference among them. ALDH1+ cells in the lamina propria were higher for Lichen Planus [2.0], followed by Leukoplakia [1.3], Lichenoid lesions [1.2] and control [1.1] (p<0.05). CONCLUSIONS: ALDH1 immunoexpression in epithelium of lichenoid potential malignant disorders did not show a contributory tool, however ALDH1 in stromal cells of lichen planus might be involved in the complex process of immune regulation associated with the pathogenesis of this disease.

Association between perceived stress and health-risk behaviours in workers.

Individuals who experience stress can engage in health-risk behaviours that may decrease work performance. The aim of this study was to determine perceived stress levels in Brazilian workers and verify whether perceived stress was associated with health-risk behaviours. Stress levels of 1,270 workers (1,019 men, 251 women) were assessed using the Perceived Stress Scale. The health-risk behaviours investigated were low intake of vegetables and fruits, daily smoking, high-risk alcohol consumption, physical inactivity, and the presence of obesity. The Student's t-test or one-way analysis of variance was used to assess differences in stress levels. Ordinal regression was used to determine the association between the degrees of stress and health-risk behaviours. Women had higher perceived stress levels than men. In addition, perceived stress levels were higher in those who had low socioeconomic status, were unmarried, had a negative perception of their health, were smokers, or had obesity. Smoking and the presence of two or more health-risk behaviours were associated with 1.84 (95% CI: 1.24-2.73) times and 1.49 (95% CI: 1.18-1.89) times higher odds of experiencing higher degrees of stress, respectively. In women, such an association was observed with the presence of obesity (odds ratio: 2.0; 95% CI: 1.01-3.98).

Prevalence of different states of glucose intolerance in Sri Lankan children and adolescents with obesity and its relation to other comorbidities.

BACKGROUND: South Asian adults have higher prevalence of obesity comorbidities than other ethnic groups. Whether this also is true for Sri Lankan children with obesity has rarely been investigated. OBJECTIVE: To investigate prevalence of glucose intolerance and other comorbidities in Sri Lankan children with obesity and compare them with Swedish children. To identify risk factors associated with glucose intolerance. SUBJECTS: A total of 357 Sri Lankan children (185 boys), aged 7 to 17 years with BMI-SDS ≥2.0 from a cross-sectional school screening in Negombo. A total of 167 subjects from this study population were matched for sex, BMI-SDS and age with 167 Swedish subjects from the ULSCO cohort for comparison. METHODS: After a 12 hour overnight fast, blood samples were collected and oral glucose tolerance test was performed. Body fat mass was assessed by bioelectrical impedance assay. Data regarding medical history and socioeconomic status were obtained from questionnaires. RESULTS: Based on levels of fasting glucose (FG) and 2 hours-glucose (2 hours-G), Sri Lankan subjects were divided into five groups: normal glucose tolerance (77.5%, n = 276), isolated impaired fasting glucose according to ADA criteria (9.0%, n = 32), isolated impaired glucose tolerance (8.4%, n = 30), combined impaired fasting glucose (IFG) + impaired glucose tolerance (IGT) (3.1%, n = 11) and type 2 diabetes mellitus (2.0%, n = 7). FG, 2 hours-insulin and educational status of the father independently increased the Odds ratio to have elevated 2 hours-G. Sri Lankan subjects had higher percentage of body fat, but less abdominal fat than Swedish subjects. CONCLUSION: High prevalence in Sri Lankan children with obesity shows that screening for glucose intolerance is important even if asymptomatic.

Association between screen time and accelerometer-measured 24-h movement behaviors in a sample of Brazilian adolescents.

OBJECTIVES: Different screen time activities may be related to sleep, physical activity, and sedentary behavior. The objective was to examine the association between self-reported screen time activities and accelerometer-measured 24-h movement behaviors. STUDY DESIGN: This was a cross-sectional study. METHODS: Adolescents' (n = 718, 50.4% girls, 16 years) sleep duration, sedentary behavior, light-intensity physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) were estimated with wrist-worn accelerometry. Time spent on screen time activities related to studying, working, watching videos, playing video games, and using social media was self-reported. Multilevel linear regressions were used to test the association between screen time with sleep, sedentary behavior, and physical activity. RESULTS: Boys and girls slept 6.4 and 6.7 h per night, spent 10.4 and 10.1 h/d in sedentary behavior, spent 4.0 and 4.4 h/d in LPA, and spent 34.7 and 29.2 min/d in MVPA, respectively. Studying was inversely related to LPA and MVPA. Working was inversely related to sleep and positively related to LPA. Watching videos was associated with lower LPA and MVPA. For boys, videogames were associated with increased sedentary behavior and lower LPA and MVPA. For girls, studying and/or using social media were associated with lower LPA and MVPA. CONCLUSIONS: Indicators of screen time were associated with different accelerometer-measured 24-h movement behaviors in this sample of Brazilian adolescents.

Biopiracy: Abolish Corporate Hijacking of Indigenous Medicinal Entities.

Biopiracy as "a silent disease" is hardly detectable because it does not leave traces frequently. The corporate hijacking of food is the most important health hazard in this era; giant commercial enterprises are using intellectual property rights to patent indigenous medicinal plants, seeds, genetic resources, and traditional medicines. The new era of biotechnology relies on the genes of living organisms as raw materials. The "Gene Rush" has thus become similar to that of the old "Gold Rush." Sri Lanka has been spotted in the top 34 biodiversity hotspots globally. Moreover, localized in the tropics, human generations in Sri Lanka have utilized the array of plant species for herbal treatments and treatment of diseases. Sri Lanka after its 30-year civil war is moving towards a solid growth and conservation of the environment which is a major component in a sustainable development where the conservation of biodiversity plays a significant role. In this paper, we present an overview of typical cases of global biopiracy, bioprospecting via introduction of cost-effective deoxyribonucleic acid (DNA) fingerprinting and international protocol with Private-Public-People Partnership concept as excellent forms of utilization of natural resources. We propose certain perspectives as scientists towards abolishing biopiracy and also to foster the fair utilization of natural resources; since the economy of most developing countries is agriculture based, the gross domestic product of the developing countries could be increased by enhanced bioprospecting via introduction of cost-effective DNA fingerprinting technologies and thus not being a pray of corporate hijacking."Biopiracy is biological theft; illegal collection of indigenous plants by corporations who patent them for their own use" (Vandana Shiva).

On the Use of Embedded Fiber Optic Sensors for Measuring Early-Age Strains in Concrete.

Detailed information about concrete behavior in real structures is an important issue in controlling its performance during its service life, and the use of embedded sensors to obtain desired information such as temperature, onset of the cracking process and evolution of strains, has gained the attention of the building concrete industry. Data obtained using this technology can provide valuable information for decision making about the need for corrective interventions that can ensure the integrity and safety of concrete structures for long period of time. This paper presents a review of the current state-of-the-art of embedded fiber optic sensors used to assess concrete information of a wide range of aspects, comprising: existing alternative technologies, characteristics and advantages, practical applications and future developments. Complementarily, the work presents preliminary results of the use of fiber optic sensors to automatically and continuously perform expansion readings of AAR in concrete elements that facilitate both the storage-with elimination of the usual interruptions for manual readings-and the availability of continuous results of expansion data that are not possible to obtain with usual AAR tests code reading recommendations.

Presentations and outcomes of interstitial lung disease and the anti-Ro52 autoantibody.

BACKGROUND: Distinct clinical presentations of interstitial lung disease (ILD) with the myositis-specific antibodies, including anti-synthetase antibodies, are well-recognized. However, the association between ILD and the myositis-associated antibodies, including anti-Ro52, is less established. Our objectives were to compare presenting phenotypes of patients with anti-Ro52 alone versus in combination with myositis-specific autoantibodies and to identify predictors of disease progression or death. METHODS: We performed a retrospective cohort study of 73 adults with ILD and a positive anti-Ro52 antibody. We report clinical features, treatment, and outcomes. RESULTS: The majority of patients with ILD and anti-Ro52 had no established connective tissue disease (78%), and one-third had no rheumatologic symptoms. Thirteen patients (17.8%) required ICU admission for respiratory failure, with 84.6% all-cause mortality. Of the 73 subjects, 85.7% had a negative SS-A, and 49.3% met criteria for idiopathic pneumonia with autoimmune features (IPAF). The 50 patients with anti-Ro52 alone were indistinguishable from patients with anti-Ro52 plus a myositis-specific autoantibody. ICU admission was associated with poor outcomes (HR 12.97, 95% CI 5.07-34.0, p < 0.0001), whereas rheumatologic symptoms or ANA > = 1:320 were associated with better outcomes (HR 0.4, 95% CI 0.16-0.97, p = 0.04, and HR 0.29, 95% CI 0.09-0.81, p = 0.03, respectively). CONCLUSIONS: Presentations of ILD with the anti-Ro52 antibody are heterogeneous, and outcomes are similar when compared to anti-Ro52 plus myositis-specific antibodies. Testing for anti-Ro52 may help to phenotype unclassifiable ILD patients, particularly as part of the serologic criteria for IPAF. Further research is needed to investigate treatment of ILD in the setting of anti-Ro52 positivity.

Validation of the Sinhala Version of the Addenbrooke's Cognitive Examination-Revised for the Detection of Dementia in Sri Lanka: Comparison with the Mini-Mental Status Examination and the Montreal Cognitive Assessment.

BACKGROUND: Sri Lanka is a rapidly aging country, where dementia prevalence will increase significantly in the future. Thus, inexpensive and sensitive cognitive screening tools are crucial. OBJECTIVES: To assess the reliability, validity, and diagnostic accuracy of the Sinhalese version of the Addenbrooke's Cognitive Examination-Revised (ACE-R s). METHOD: The ACE-R was translated into Sinhala with cultural and linguistic adaptations and administered, together with the Sinhala version of the Montreal Cognitive Assessment (MoCA), to 99 patients with dementia and 93 gender-matched controls. RESULTS: The ACE-R s cutoff score for dementia was 80 (sensitivity 91.9%, specificity 76.3%). The areas under the curve for the ACE-R s, Mini-Mental State Examination (MMSE) and MoCA were 0.90, 0.86, and 0.86, respectively. The -ACE-R s had good interrater reliability (intraclass correlation = 0.94), test-retest reliability (intraclass correlation = 0.99), and internal consistency (Cronbach's α = 0.8442). CONCLUSIONS: The ACE-R s is sensitive, specific and reliable to detect dementia in persons aged ≥50 years in a Sinhala-speaking population and its diagnostic accuracy is superior to previously validated tools (MMSE and MoCA).

Use of nanotechnology for infectious disease diagnostics: application in drug resistant tuberculosis.

BACKGROUND: The increased transmission of multidrug-resistant (MDR) tuberculosis (TB) poses a challenge to tuberculosis prevention and control in Sri Lanka. Isoniazid (INH) is a key element of the first line anti tuberculosis treatment regimen. Resistance to INH may lead to development of MDR TB. Therefore, early detection of INH resistance is important to curb spread of resistance. Due to the limited availability of rapid molecular methods for detection of drug resistance in Sri Lanka, this study was aimed at developing a simple and rapid gold nanoparticle (AuNP) based lateral flow strip for the simultaneous detection of the most common INH resistance mutation (katG S315 T, 78.6%) and Mycobacterium tuberculosis (MTb). METHODS: Lateral flow strip was designed on an inert plastic backing layer containing a sample pad, nitrocellulose membrane and an absorption pad. Biotin labeled 4 capture probes which separately conjugated with streptavidin were immobilized on the nitrocellulose. The test sample was prepared by multiplex PCR using primers to amplify codon 315 region of the katG gene and MTb specific IS6110 region. The two detection probes complementary to the 5' end of each amplified fragment was conjugated with gold nanoparticles (20 nm) and coupled with the above amplified PCR products were applied on the sample pad. The hybridization of the amplified target regions to the respective capture probes takes place when the sample moves towards the absorption pad. Positive hybridization is indicated by red colour lines. RESULTS: The three immobilized capture probes on the strip (for the detection of TB, katG wild type and mutation) were 100 and 96.6% specific and 100 and 92.1% sensitive respectively. CONCLUSION: The AuNP based lateral flow assay was capable of differentiating the specific mutation and the wild type along with MTb identification within 3 h.

Ultrasonographic length of morphologically-normal kidneys in children presented to a premier tertiary healthcare setting of Sri Lanka.

BACKGROUND: Accurate prediction of reference ranges of renal lengths facilitates clinical decision making. Currently a single renal-length-reference chart is used for both kidneys, which is solely based on the age of the child without adjusting for anthropometrics. Objective of the study is to assess the length of morphologically-normal kidneys ultrasonically and to build models to predict the renal lengths of children presenting at the Radiology Department of Lady Ridgeway Hospital for Children. METHODS: A descriptive cross sectional study was done among 424 children with 233 males and 191 females at the study setting. Study population included children undergoing abdominal ultrasound scans for indications not related to renal disease. Children with a family history of renal diseases or with morphologically-abnormal kidneys were excluded. Bipolar-lengths of kidneys, gender and anthropometrics were documented. Having tested for assumptions, Wilcoxon-signed rank test, Mann-Whitney U test and multiple linear regression were used. RESULTS: The mean (SD) bipor-length of right and left kidneys were 6.83 (1.43) and 7.05 (1.36) respectively (p < 0.001). Age, height and weight were significantly correlated with the renal lengths (p < 0.05). Until 16 months, there was a significant difference between the renal lengths between males and females (P < 0.05). Yet the association with gender was not significant from 17 months and in overall. Until 16 months, the best linear-regression equation (p < 0.001) for the left kidney was; 3.827 +  0.019(length in centimeters) +  0.141(weight in kilograms) - 0.023(age in months) - 0.347(for male sex). For the right kidney, it was; 3.888 + 0.020(length or height) + 0.121(weight) - 0.037(age) - 0.372 (for male sex). The respective R squares were 59.2 and 53.5% with VIF (Variance-Inflation-Factor) ranging from 1.06 to 2.08. From 17 months, best equation for left kidney (p < 0.001) was; 5.651+ 0.022(age) + 0.01(BMI). For right kidney it was; 5.336 + 0.022(age) + 0.012(BMI). The R squares were 62.5 and 66.1% with VIF being 1. CONCLUSIONS: The established models explain more variability for children above 17 months. Both renal lengths are affected significant by the body's' anthropometric parameters. For each kidney, separate normograms of renal lengths which are local-context-specific must be prepared. Further research must be promoted.

Arthritis and use of hydroxychloroquine associated with a decreased risk of macrophage activation syndrome among adult patients hospitalized with systemic lupus erythematosus.

Background Macrophage activation syndrome (MAS) is an uncommon but serious complication of systemic lupus erythematosus (SLE). We aimed to identify factors associated with MAS among adult hospitalized SLE patients. Methods Within the Brigham and Women's Hospital (BWH) Lupus Center Registry, we identified adult SLE patients > age 17 who had been hospitalized from 1970 to 2016, with either ferritin > 5000 ng/ml during admission or "macrophage activation syndrome" or "MAS" in discharge summary. We confirmed MAS by physician diagnosis in medical record review. We matched each hospitalized SLE patient with MAS to four SLE patients hospitalized without MAS (by SLE diagnosis date ±1 year). We employed conditional logistic regression models to identify clinical factors associated with MAS among hospitalized SLE patients. Results Among 2094 patients with confirmed SLE, we identified 23 who had a hospitalization with MAS and compared them to 92 hospitalized without MAS. Cases and controls had similar age at SLE diagnosis (29.0 vs. 30.5, p = 0.60), and hospital admission (43.0 vs. 38.3, p = 0.80), proportion female (78% vs. 84%, p = 0.55), and time between SLE diagnosis and hospitalization (1971 vs. 1732 days, p = 0.84). Arthritis (OR 0.04 (95% CI 0.004-0.35)) and hydroxychloroquine use (OR 0.18 (95% CI 0.04-0.72)) on admission were associated with decreased MAS risk. Admission Systemic Lupus Erythematosus Disease Activity Index scores (30 vs. 19, p = 0.002) and lengths of stay (16 days vs. 3 days, p < 0.0001) were much higher among cases. Death during hospitalization was 19% among cases and 3% among controls ( p = 0.03). Conclusions In this case-control study of hospitalized adult SLE patients, arthritis and hydroxychloroquine use at hospital admission were associated with decreased MAS risk. Further studies are needed to validate these factors associated with lowered MAS risk.

Clinicopathologic and immunohistochemical characterization of 14 cases of angioleiomyomas in oral cavity.

BACKGROUND: Angioleiomyoma (ALM) is a benign neoplasm that originates from vascular smooth muscle. It is extremely rare in oral cavity. The objective of this study was to evaluate the clinicopathological and immunohistochemical characteristics of all oral angioleiomyomas registered in a Center of Diagnosis of Oral Diseases from 1959 to 2017. MATERIAL AND METHODS: Slides from 14 cases of ALM stained with hematoxylin and eosin (H&E) were analyzed to confirm the diagnosis. Moreover, an immunohistochemical panel with alpha-smooth muscle actin (alpha-SMA), desmin, AE1/AE3, CD68, S-100, and CD34 antibodies was performed to evaluate semi-quantitatively the positive cells. RESULTS: ALM correspond to 0.08% of all benign oral tumors analyzed during the 57-year period. The mean age of the patients was 45 years with a predilection to males (58%). The most frequently reported site was lips (50%). Microscopic analysis on H&E sections revealed similar pattern in all cases, showing well-circumscribed and encapsulated tumors, characterized by a proliferation of smooth muscle cells and wide vascular spaces of varying sizes. The predominant immuno profiles were: alpha-smooth muscle actin (alpha-SMA) positive (strong immunoreactivity); positive variable pattern for desmin, negative immunoprofile for AE1/AE3, CD68, and S-100. The endothelial cells of vascular spaces were CD34+. CONCLUSIONS: Based on the results, the alpha-SM actin can be elected as a good marker for angioleiomyomas and can help the confirmation of the morphologic diagnosis of this lesion.

Evaluation of the plasmatic level of mepivacaine in different anatomical regions.

BACKGROUND: To evaluate the serum level of the local anesthetic mepivacaine 3% without vasoconstrictor in patients who underwent procedures performed in the anterior and posterior maxilla, through a method of possible extraction to quantify it in human plasma by high performance liquid chromatography (HPLC). MATERIAL AND METHODS: This was a hybrid study consisting of 18 patients (7 females and 11 males) classified as ASA I, adults and with normal body mass index, submitted to procedures in the anterior region (group I) and posterior region of the maxilla (group II). For 40 minutes, five 6 ml blood samples were collected every 10 minutes after infiltrative injection in each region of the maxilla. Serum levels of the drug were obtained through HPLC. Blood pressure (BP) and heart rate (HR) were measured throughout the procedure. RESULTS: When compared to the general average of the concentrations of each group, significant values (p <0.05) with greater absorption were observed for the anterior region of the maxilla (group I). There was no significant difference when comparing blood pressure (BP) and heart rate (HR) values. CONCLUSIONS: The concentrations found are safe for infiltrative anesthesia in the analyzed patients, there was a higher plasma level of the local anesthetic in the anterior region of the maxilla and there was no change in HR and BP in relation to the anesthetized area.

Elucidating the design principles of photosynthetic electron-transfer proteins by site-directed spin labeling EPR spectroscopy.

Site-directed spin labeling electron paramagnetic resonance (SDSL EPR) spectroscopy is a powerful tool to determine solvent accessibility, side-chain dynamics, and inter-spin distances at specific sites in biological macromolecules. This information provides important insights into the structure and dynamics of both natural and designed proteins and protein complexes. Here, we discuss the application of SDSL EPR spectroscopy in probing the charge-transfer cofactors in photosynthetic reaction centers (RC) such as photosystem I (PSI) and the bacterial reaction center (bRC). Photosynthetic RCs are large multi-subunit proteins (molecular weight≥300 kDa) that perform light-driven charge transfer reactions in photosynthesis. These reactions are carried out by cofactors that are paramagnetic in one of their oxidation states. This renders the RCs unsuitable for conventional nuclear magnetic resonance spectroscopy investigations. However, the presence of native paramagnetic centers and the ability to covalently attach site-directed spin labels in RCs makes them ideally suited for the application of SDSL EPR spectroscopy. The paramagnetic centers serve as probes of conformational changes, dynamics of subunit assembly, and the relative motion of cofactors and peptide subunits. In this review, we describe novel applications of SDSL EPR spectroscopy for elucidating the effects of local structure and dynamics on the electron-transfer cofactors of photosynthetic RCs. Because SDSL EPR Spectroscopy is uniquely suited to provide dynamic information on protein motion, it is a particularly useful method in the engineering and analysis of designed electron transfer proteins and protein networks. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.

Gender-specific impairment of in vitro sinoatrial node chronotropic responses and of myocardial ischemia tolerance in rats exposed prenatally to betamethasone.

Excessive fetal glucocorticoid exposure has been linked to increased susceptibility to hypertension and cardiac diseases in the adult life, a process called fetal programming. The cardiac contribution to the hypertensive phenotype of glucocorticoid-programmed progeny is less known, therefore, we investigated in vitro cardiac functional parameters from rats exposed in utero to betamethasone. Pregnant Wistar rats received vehicle (VEH) or betamethasone (BET, 0.1mg/kg, i.m.) at gestational days 12, 13, 18 and 19. Male and female offspring were killed at post-natal day 30 and the right atrium (RA) was isolated to in vitro evaluation of drug-induced chronotropic responses. Additionally, whole hearts were retrograde-perfused in a Langendorff apparatus and infarct size in response to in vitro ischemia/reperfusion (I/R) protocol was evaluated. Male and female progeny from BET-exposed pregnant rats had reduced birth weight, a hallmark of fetal programming. Male BET-progeny had increased basal RA rate, impaired chronotropic responses to noradrenaline and adenosine, and increased myocardial damage to I/R. Though a 12-fold reduction in the negative chronotropic responses to adenosine, the effects of non-metabolisable adenosine receptor agonists 5'-(N-ethylcarboxamido)adenosine or 2-Chloro-adenosine were not different between VEH- and BET-exposed male rats. BET-exposed female offspring presented no cardiac dysfunction. Prenatal BET exposure engenders male-specific impairment of sinoatrial node function and on myocardial ischemia tolerance resulting, at least in part, from an increased adenosine metabolism in the heart. In light of the importance of adenosine in the cardiac physiology our results suggest a link between reduced adenosinergic signaling and the cardiac dysfunctions observed in glucocorticoid-induced fetal programming.

Induction of haem oxygenase-1 increases infection of dog macrophages by L. infantum.

We aimed to induce and inhibit HO-1, ascertaining its effect on infection rate, parasite load and the levels of superoxide, reactive oxygen species (ROS), nitric oxide (NO), TNF-alpha and IL-10 in cultured macrophages from healthy dogs infected by Leishmania infantum. Macrophages obtained from 15 healthy dogs were cultured alone or infected with L. infantum, with or without association of HO-1 inducer and inhibitor. The infection rate and the parasite load were determined by the number of infected macrophages and number of promastigotes per macrophage, respectively. HO-1 levels and gene expression, as well as IL-10 and TNF-alpha levels were also measured in these cultures. Superoxide, ROS and NO levels in macrophages were measured through flow cytometry. Induction of HO-1 increased the infection rate and parasite load, while its inhibition decreased the infection rate and IL-10 production. There was a positive correlation between HO-1 and infection rate or parasite load. Increased infection rate was associated with decreased superoxide, ROS and NO levels. Induction of HO-1 metabolism in dogs infected by L. infantum is possibly one of the mechanisms responsible for increasing the infection of macrophages, mainly through reduction in the oxidative and nitrosative metabolisms of these cells.

Variation in susceptibility of different breeds of sheep to Mycobacterium avium subspecies paratuberculosis following experimental inoculation.

Exposure to Mycobacterium avium subspecies paratuberculosis (MAP) does not always lead to Johne's disease. Understanding differences in disease susceptibility of individual animals is a key aspect to controlling mycobacterial diseases. This study was designed to examine the susceptibility or resistance of various breeds of sheep to MAP infection. Merino, Suffolk first cross Merino, Border Leicester, and Poll Dorset sheep were orally inoculated with MAP and monitored for 14 months. Clinical disease occurred more frequently in the Merino (42%) and Suffolk first cross Merino (36%) compared to the Border Leicester (12%) and Poll Dorset (11%) breeds. Infection risk, as determined by culture of gut and associated lymphoid tissues, ranged from 75% for the Suffolk first cross Merino to 47% for the Poll Dorset sheep. Significant differences were identified in the site in the intestines of the most severe histopathological lesions and the immune responses to infection between the breeds. However, there was no difference in faecal MAP shedding by clinical cases between breeds. All breeds tested were susceptible to MAP infection, as determined by infection and clinical disease development, although there were differences in the proportions of diseased animals between the breeds. Poll Dorset and Border Leicester sheep were more resilient to MAP infection but there was evidence that more animals could have developed disease if given more time. These findings provide evidence of potential differential disease susceptibility between breeds, further our understanding of disease pathogenesis and risks of disease spread, and may have an influence on control programs for paratuberculosis.