1731. Immune Dysregulation in Mucormycosis

Background

Mucormycosis is a fatal fungal infection with unique predisposition to infect diabetics. Dysregulated adaptive immunity contributes to the pathogenesis in all fungal diseases, but activated Th17 cells have laid a new dimension to chronic inflammatory response which was previously attributed to uncontrolled Th1 response. We attempted to study the Th17 and T regulatory (Treg) immune response in diabetic patients with mucormycosis and compared the data with a healthy control and a T2DM case without fungal infection. In addition we could follow-up one patient post 6-month treatment and performed immunological studies.

Methods

2 mL of blood samples were collected in EDTA vial from two patients who were suffering from diabetes with mucormycosis for immunological investigations. Samples were also taken from age-matched T2DM patient without fungal infection and a healthy volunteer as controls for T-cell parameters. Repeat blood sample was taken to study immune parameters in one patient who was followed up after 6 months. The expression of various T-cell markers was analyzed by immunostaining with the antibodies against CD3, CD4, CD25, CD161, IL-23R [Becton Dickinson (BD) PharMingen]. Fluorescence profiles were analyzed using Flow Jo software (BD Biosciences). The results are expressed as a percentage of positive cells.

Results

The percentages of CD4+ cells were low in both patients when compared with and healthy control but it is much higher in diabetes case when compared with others. CD161+ cell population was higher in both patients when compared with healthy control and diabetic patient without fungal infection. The percentage of IL23R+ cells was significantly high in patient before treatment when compared with, healthy control and diabetics. and decline after treatment. The percentage positivity of CD25+ cells was highest in healthy control when compared with others. The profile of CD25+ cells was comparatively similar in patient before treatment and diabetics but we found a higher percentage, in patients after treatment.

Conclusion

The findings in this study imminently indicate the mechanism of immune dysregulation involving Th17 and Treg pathways in mucormycosis and provide evidence that restoration of Th17/Treg may be considered as a therapeutic option for long-term benefit in diabetics.

Disclosures

All authors: No reported disclosures.

Structural and biochemical studies of phosphopantetheine adenylyltransferase from Acinetobacter baumannii with dephospho-coenzyme A and coenzyme A

Phosphopantetheine adenylyl transferase catalyzes a rate limiting penultimate step of the multistep reaction which produces coenzyme A (CoA) as a final product. CoA is required as an essential cofactor in a number of metabolic reactions. Therefore inhibiting the function of this enzyme will lead to cell death in bacteria. Acinetobacter baumannii is multi drug resistant pathogen and causes infections in immunocompromised patients. AbPPAT has been cloned, expressed, purified and crystallized and structures of two complexes of AbPPAT with dephospho coenzyme A (dPCoA) and coenzyme A (CoA) have been determined. Both dPCoA and CoA molecules are observed in the substrate binding site of AbPPAT. A comparison with the structures of the complexes of PPAT from other species shows that the orientations of dPCoA are identical in all the structures. On the other hand, as observed from the structures of the complexes of CoA with PPAT, the orientations of CoA are found to differ considerably. This shows that the substrates occupy identical positions in the substrate binding sites of enzymes whereas the positions of inhibitors may differ. The binding studies carried out using fluorescence method and surface plasmon resonance techniques showed that binding affinity of CoA towards AbPPAT is nearly three times higher than that of dPCoA.

Tracking the adoption of bread wheat varieties in Afghanistan using DNA fingerprinting

BACKGROUND

Wheat is the most important staple crop in Afghanistan and accounts for the main part of cereal production. However, wheat production has been unstable during the last decades and the country depends on seed imports. Wheat research in Afghanistan has emphasized releases of new, high-yielding and disease resistant varieties but rates of adoption of improved varieties are uncertain. We applied DNA fingerprinting to assess wheat varieties grown in farmers' fields in four Afghan provinces.

RESULTS

Of 560 samples collected from farmers' fields during the 2015-16 cropping season, 74% were identified as varieties released after 2000, which was more than the number reported by farmers and indicates the general prevalence of use of improved varieties, albeit unknowingly. At the same time, we found that local varieties and landraces have been replaced and were grown by 4% fewer farmers than previously reported. In 309 cases (58.5%), farmers correctly identified the variety they were growing, while in 219 cases (41.5%) farmers did not. We also established a reference library of released varieties, elite breeding lines, and Afghan landraces, which confirms the greater genetic diversity of the landraces and their potential importance as a genetic resource.

CONCLUSIONS

Our study is the first in wheat to apply DNA fingerprinting at scale for an accurate assessment of wheat varietal adoption and our findings point up the importance of DNA fingerprinting for accuracy in varietal adoption studies.

Surface Exclusion Revisited: Function Related to Differential Expression of the Surface Exclusion System of Bacillus subtilis Plasmid pLS20

During conjugation a genetic element is transferred from a bacterial donor to a recipient cell via a connecting channel. It is the major route responsible for the spread of antibiotic resistance. Conjugative elements can contain exclusion system(s) that inhibit its transfer to a cell already harboring the element. Our limited knowledge on exclusion systems is mainly based on plasmids of Gram-negative bacteria. Here we studied the conjugative plasmid pLS20 of the Gram-positive Bacillus subtilis. We demonstrate that pLS20 contains an exclusion system and identified the single gene responsible for exclusion, named sespLS20 , which is embedded in the conjugation operon. SespLS20 is the founding member of a novel family of surface exclusion proteins encoded by conjugative elements of Gram-positive origin. We show that the extent of surface exclusion correlates with the level of sespLS20 expression, and that sespLS20 is expressed at basal low-levels in all donor cells but becomes highly expressed in conjugating cells. Accordingly, the transfer of pLS20 from a conjugation-primed donor cell to an un-primed or conjugation-primed donor is inhibited moderately and very efficiently, respectively. The consequences of this differential regulation, which appears to be a conserved feature of surface exclusion systems of Gram-positive and Gram-negative origin, are discussed.

Emergence of three-dimensional order and structure in growing biofilms

Surface-attached bacterial biofilms are self-replicating active liquid crystals and the dominant form of bacterial life on earth (1-4). In conventional liquid crystals and solid-state materials, the interaction potentials between the molecules that comprise the system determine the material properties. However, for growth-active biofilms it is unclear whether potential-based descriptions can account for the experimentally observed morphologies, and which potentials would be relevant. Here, we overcame previous limitations of single-cell imaging techniques (5,6) to reconstruct and track all individual cells inside growing three-dimensional (3D) biofilms with up to 10,000 individuals. Based on these data, we identify, constrain, and provide a microscopic basis for an effective cell-cell interaction potential, which captures and predicts the growth dynamics, emergent architecture, and local liquid crystalline order of Vibrio cholerae biofilms. Furthermore, we show how external fluid flows control the microscopic structure and 3D morphology of biofilms. Our analysis implies that local cellular order and global biofilm architecture in these active bacterial communities can arise from mechanical cell-cell interactions, which cells can modulate by regulating the production of particular matrix components. These results establish an experimentally validated foundation for improved continuum theories of active matter and thereby contribute to solving the important problem of controlling biofilm growth.

Pain during Injection of Propofol: The Effect of Prior Administration of Ephedrine

Propofol causes pain on intravenous injection in 28 to 90% of patients. A number of techniques have been tried to minimize propofol-induced pain, with variable results. In a randomized, double-blind, placebo-controlled trial, we compared the efficacy of ephedrine 30 μg/kg pretreatment to lignocaine 40 mg for prevention of propofol-induced pain. Ninety-three adult patients, ASA 1 and 2, undergoing elective laparoscopic cholecystectomy were randomly assigned to three groups of 31 each. Group 1 received normal saline, group 2 received lignocaine 2% (40 mg) and group 3 received 30 μg/kg ephedrine. All pretreatment drugs were made up to 2 ml. Pain at the time of propofol injection was assessed on a four-point scale: 0=no pain, 1=mild pain, 2=moderate pain, and 3=severe pain. Twenty-seven patients (87%) of ephedrine pretreatment patients had pain during intravenous injection of propofol as compared to 24 (77%) in the normal saline group. In the lignocaine group, propofol-induced pain was observed in only 13 (42%) when compared with other study groups (P<0.05). Pretreatment with ephedrine 30 μg/kg did not attenuate pain associated with intravenous injection of propofol, nor did it improve haemodynamic stability during induction. However, pretreatment with 2% lignocaine (40 mg) was effective in attenuating propofol-associated pain.

Laser Acceleration of Highly Energetic Carbon Ions Using a Double-Layer Target Composed of Slightly Underdense Plasma and Ultrathin Foil

We report the experimental generation of highly energetic carbon ions up to 48 MeV per nucleon by shooting double-layer targets composed of well-controlled slightly underdense plasma and ultrathin foils with ultraintense femtosecond laser pulses. Particle-in-cell simulations reveal that carbon ions are ejected from the ultrathin foils due to radiation pressure and then accelerated in an enhanced sheath field established by the superponderomotive electron flow. Such a cascaded acceleration is especially suited for heavy ion acceleration with femtosecond laser pulses. The breakthrough of heavy ion energy up to many tens of MeV/u at a high repetition rate would be able to trigger significant advances in nuclear physics, high energy density physics, and medical physics.

Response Surface Methodology-Genetic Algorithm Based Medium Optimization, Purification, and Characterization of Cholesterol Oxidase from Streptomyces rimosus

The applicability of the statistical tools coupled with artificial intelligence techniques was tested to optimize the critical medium components for the production of extracellular cholesterol oxidase (COD; an enzyme of commercial interest) from Streptomyces rimosus MTCC 10792. The initial medium component screening was performed using Placket-Burman design with yeast extract, dextrose, starch and ammonium carbonate as significant factors. Response surface methodology (RSM) was attempted to develop a statistical model with a significant coefficient of determination (R² = 0.89847), followed by model optimization using Genetic Algorithm (GA). RSM-GA based optimization approach predicted that the combination of yeast extract, dextrose, starch and ammonium carbonate at concentrations 0.99, 0.8, 0.1, and 0.05 g/100 ml respectively, has resulted in 3.6 folds increase in COD production (5.41 U/ml) in comparison with the un-optimized medium (1.5 U/ml). COD was purified 10.34 folds having specific activity of 12.37 U/mg with molecular mass of 54 kDa. The enzyme was stable at pH 7.0 and 40 °C temperature. The apparent Michaelis constant (K_m) and V_max values of COD were 0.043 mM and 2.21 μmol/min/mg, respectively. This is the first communication reporting RSM-GA based medium optimization, purification and characterization of COD by S. rimosus isolated from the forest soil of eastern India.

Candida auris in critically ill patients: Emerging threat in intensive care unit of hospitals

Candida auris has emerged as the multi-drug resistant non-albican candida species in critically ill patients admitted to intensive care units (ICU) causing bloodstream and other infections. It has often been misidentified as Candida famata, Candida sake, Rhodotorula glutinis, or Saccharomyces cerevisiae and Candida haemulonii by automated identification systems. We, in this study, discuss three patients who acquired Candida auris infection after 15 to 20days of their stay in medical ICU. Medical equipment, use of multiple antibiotics, and poor hand hygiene are the most probable predisposing factors attributing to its colonization at multiple anatomical sites leading to bloodstream infection. Candida auris might substantially contaminate the environment of colonized or infected patients making its eradication difficult. Patient screening for Candida auris, especially during prolonged ICU stays, along with strict infection prevention and control strategies needs to be adopted to break its persistence.

No yield penalty under favorable conditions paving the way for successful adoption of flood tolerant rice

Flooding is one of the major constraints for rice production in rainfed lowlands, especially in years and areas of high rainfall. Incorporating the Sub1 (Submergence1) gene into high yielding popular varieties has proven to be the most feasible approach to sustain rice production in submergence-prone areas. Introgression of this QTL into popular varieties has resulted in considerable improvement in yield after flooding. However, its impact under non-flooded conditions or years have not been thoroughly evaluated which is important for the farmers to accept and adopt any new version of their popular varieties. The present study was carried out to evaluate the effect of Sub1 on grain yield of rice in different genetic backgrounds, under non-submergence conditions, over years and locations. The study was carried out using head to head trials in farmer’s fields, which enable the farmers to more accurately compare the performance of Sub1 varieties with their recurrent parents under own management. The data generated from different head to head trials revealed that the grain yield of Sub1 varieties was either statistically similar or higher than their non-Sub1 counterparts under non-submergence conditions. Thus, Sub1 rice varieties show no instance of yield penalty of the introgressed gene.

Anesthetic challenges of extrinsic trachea-bronchial compression due to posterior mediastinal mass: Our experience with a large esophageal mucocele

Large posterior mediastinal masses may lead threatening complications such as critical tracheobronchial compression. Airway management in these individuals is a challenge and being a lower airway obstruction; rescue strategies are limited. We encountered one such case of a large esophageal mucocele causing extrinsic tracheobronchial compression. We have described the anesthetic management of this case using awake fiber-optic assessment followed by intubation. Close communication with the surgical team, meticulous planning of airway management, and early drainage of the mucocele are the cornerstones of management in such patients.

Rapid detection of ethambutol-resistant Mycobacterium tuberculosis in clinical specimens by real-time polymerase chain reaction hybridisation probe method

Background

Early diagnosis of drug resistance (DR) to ethambutol (EMB) in tuberculosis (TB) remains a challenge. Simple and reliable method (s) are needed for rapid detection of DR Mycobacterium tuberculosis (MTB) in clinical specimens.

Objectives

The aim of this study was to design fluorescence resonance energy transfer hybridisation probe-based real-time polymerase chain reaction (PCR) method for the early detection of EMB-resistant MTB direct from clinical sputa.

Materials and Methods

Primers and probes were designed against 306 codon of embB gene which is commonly associated with EMB resistance. A comparative study was done between Lowenstein-Jenson (L-J) proportion and hybridisation probe-based real-time PCR method for susceptibility testing. DNA sequencing was used in nine representative isolates to validate the efficiency of real-time PCR method to detect emb306 mutation of MTB.

Results

A total of 52 clinical sputum samples and corresponding culture isolates (from category II pulmonary TB cases) were included in this study. Out of 52 MTB isolates, 32 and 20 were resistant and susceptible to EMB, respectively, as determined by L-J proportion method. Real-time PCR showed 95% specificity, 75% sensitivity and 82.69% accuracy when compared with L-J proportion method. A 100% of concordance was observed by validating the real-time PCR results with DNA sequencing.

Conclusions

Our real-time PCR hybridisation probe method promises for rapid detection of EMB-resistant MTB directly from clinical specimens. However, future studies and modifications of method by incorporating other potential loci along with targeted mutation (emb306) are still required to increase the sensitivity of method.

Ambient black carbon particulate matter in the coal region of Dhanbad, India

Light-absorbing, atmospheric particles have gained greater attention in recent years because of their direct and indirect impacts on regional and global climate. Atmospheric black carbon (BC) aerosol is a leading climate warming agent, yet uncertainties in the global direct aerosol radiative forcing remain large. Based on a year of aerosol absorption measurements at seven wavelengths, BC concentrations were investigated in Dhanbad, the coal capital of India. Coal is routinely burned for cooking and residential heat as well as in small industries. The mean daily concentrations of ultraviolet-absorbing black carbon measured at 370nm (UVBC) and black carbon measured at 880nm (BC) were 9.8±5.7 and 6.5±3.8μgm^-3, respectively. The difference between UVBC and BC, Delta-C, is an indicator of biomass or residential coal burning and averaged 3.29±4.61μgm^-3. An alternative approach uses the Ǻngstrom Exponent (AE) to estimate the biomass/coal and traffic BC concentrations. Biomass/coal burning contributed ~87% and high temperature, fossil-fuel combustion contributed ~13% to the annual average BC concentration. The post-monsoon seasonal mean UVBC values were 10.9μgm^-3 and BC of 7.2μgm^-3. Potential source contribution function analysis showed that in the post-monsoon season, air masses came from the central and northwestern Indo-Gangetic Plains where there is extensive agricultural burning. The mean winter UVBC and BC concentrations were 15.0 and 10.1μgm^-3, respectively. These higher values were largely produced by local sources under poor dispersion conditions. The direct radiative forcing (DRF) due to UVBC and BC at the surface (SUR) and the top of the atmosphere (TOA) were calculated. The mean atmospheric heating rates due to UVBC and BC were estimated to be 1.40°Kday^-1 and 1.18°Kday^-1, respectively. This high heating rate may affect the monsoon circulation in this region.

Self-Perception of Halitosis among Undergraduate Students of Kathmandu University School of Medical Sciences - A Questionnaire Based Study

Background Halitosis is a frequently reported oral health problem worldwide with a prevalence rate of 10-30% in the general population. It is defined as the disagreeable or foul smelling breath originating consistently from a person's oral cavity. It not only effects the normal daily life activities of the patient but also bring humiliation, reduced self- esteem, ultimately resulting into decreased quality of life. Objective To determine the self-perception of halitosis among undergraduate students of different medical branches of Kathmandu University School of Medical Sciences (KUSMS); Kavre, Nepal. Method A descriptive cross-sectional epidemiological survey was conducted among undergraduate students of Physiotherapy, B.Sc Nursing, Bachelor of Nursing Sciences (BNS), MBBS and BDS program of Kathmandu University School of Medical Sciences, Dhulikhel. A self-administered questionnaire was developed and were distributed among 500 undergraduate students. Result Out of total 500 distributed questionnaires, 406 were completely filled and returned giving an overall response of 81.2%, in which 70 (89.7%) male and 280 (85.4%) female students from different medical branches were aware of the term halitosis. Among them 29 (7.14%) of students think that they suffer from halitosis. Similarly 178 (43.84%) students had severe impact of halitosis on their social life while 153 (37.68%) and 62 (15.27%) students had moderate and mild impact respectively. Conclusion Due to the multifactorial complexity of halitosis, further longitudinal studies including objective assessment of malodor are required to determine its prevalence and to further investigate the association of this problem with other etiological factors in the context of Nepal. Also, curriculum of different fields should be modified to include this simple but very necessary topic.

Vibrio cholerae Combines Individual and Collective Sensing to Trigger Biofilm Dispersal

Bacteria can generate benefits for themselves and their kin by living in multicellular, matrix-enclosed communities, termed biofilms, which are fundamental to microbial ecology and the impact bacteria have on the environment, infections, and industry [1, 2, 3, 4, 5, 6]. The advantages of the biofilm mode of life include increased stress resistance and access to concentrated nutrient sources [3, 7, 8]. However, there are also costs associated with biofilm growth, including the metabolic burden of biofilm matrix production, increased resource competition, and limited mobility inside the community [9, 10, 11]. The decision-making strategies used by bacteria to weigh the costs between remaining in a biofilm or actively dispersing are largely unclear, even though the dispersal transition is a central aspect of the biofilm life cycle and critical for infection transmission [12, 13, 14]. Using a combination of genetic and novel single-cell imaging approaches, we show that Vibrio cholerae integrates dual sensory inputs to control the dispersal response: cells use the general stress response, which can be induced via starvation, and they also integrate information about the local cell density and molecular transport conditions in the environment via the quorum sensing apparatus. By combining information from individual (stress response) and collective (quorum sensing) avenues of sensory input, biofilm-dwelling bacteria can make robust decisions to disperse from large biofilms under distress, while preventing premature dispersal when biofilm populations are small. These insights into triggers and regulators of biofilm dispersal are a key step toward actively inducing biofilm dispersal for technological and medical applications, and for environmental control of biofilms.

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Cells in V. cholerae biofilms decide to disperse by combining two sensory mechanisms

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Quorum sensing and RpoS provide information on different environmental parameters

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Integration of both sensory inputs yields robust and optimal dispersal decisions

Identification of mega-environments and rice genotypes for general and specific adaptation to saline and alkaline stresses in India

In the present study, a total of 53 promising salt-tolerant genotypes were tested across 18 salt-affected diverse locations for three years. An attempt was made to identify ideal test locations and mega-environments using GGE biplot analysis. The CSSRI sodic environment was the most discriminating location in individual years as well as over the years and could be used to screen out unstable and salt-sensitive genotypes. Genotypes CSR36, CSR-2K-219, and CSR-2K-262 were found ideal across years. Overall, Genotypes CSR-2K-219, CSR-2K-262, and CSR-2K-242 were found superior and stable among all genotypes with higher mean yields. Different sets of genotypes emerged as winners in saline soils but not in sodic soils; however, Genotype CSR-2K-262 was the only genotype that was best under both saline and alkaline environments over the years. The lack of repeatable associations among locations and repeatable mega-environment groupings indicated the complexity of soil salinity. Hence, a multi-location and multi-year evaluation is indispensable for evaluating the test sites as well as identifying genotypes with consistently specific and wider adaptation to particular agro-climatic zones. The genotypes identified in the present study could be used for commercial cultivation across edaphically challenged areas for sustainable production.

Structural dynamics of RbmA governs plasticity of Vibrio cholerae biofilms

Biofilm formation is critical for the infection cycle of Vibrio cholerae. Vibrio exopolysaccharides (VPS) and the matrix proteins RbmA, Bap1 and RbmC are required for the development of biofilm architecture. We demonstrate that RbmA binds VPS directly and uses a binary structural switch within its first fibronectin type III (FnIII-1) domain to control RbmA structural dynamics and the formation of VPS-dependent higher-order structures. The structural switch in FnIII-1 regulates interactions in trans with the FnIII-2 domain, leading to open (monomeric) or closed (dimeric) interfaces. The ability of RbmA to switch between open and closed states is important for V. cholerae biofilm formation, as RbmA variants with switches that are locked in either of the two states lead to biofilms with altered architecture and structural integrity.

CR-39 track detector for multi-MeV ion spectroscopy

We present the characteristics of track formation on the front and rear surfaces of CR-39 produced by laser-driven protons and carbon ions. A methodological approach, based on bulk etch length, is proposed to uniquely characterize the particle tracks in CR-39, enabling comparative description of the track characteristics in different experiments. The response of CR-39 to ions is studied based on the energy dependent growth rate of the track diameter to understand the intrinsic particle stopping process within the material. A large non-uniformity in the track diameter is observed for CR-39 with thickness matching with the stopping range of particles. Simulation and experimental results show the imprint of longitudinal range straggling for energetic protons. Moreover, by exploiting the energy dependence of the track diameter, the energy resolution (δE/E) of CR-39 for few MeV protons and Carbon ion is found to be about 3%.

Gold nanotriangles: scale up and X-ray radiosensitization effects in mice

In the past decade, there has been considerable interest in radiosensitization using gold nanoparticles that accumulate specifically in cancerous tissue while sparing normal tissues. Despite this interest, it remains unclear which nanoparticle morphologies, cellular uptake, or cytoplasmic distribution elicit optimal radiosensitization. We introduce gold nanotriangles (AuNTs) as a possible X-ray radiotherapy sensitizer. In this study, we first explored a large-scale synthetic method for the production of high quality monodisperse AuNTs. Second, we conducted in vitro and in vivo experiments to evaluate the effect of PEGylated AuNTs (pAuNTs) on cellular uptake, cytotoxicity, bio-distribution, and radiosensitization on radiation-resistant human Glioblastoma Multiforme (GBM) cells. Our results suggest that the new scale up synthesis methodology consistently produced high quality AuNTs and pAuNTs which had nonspecific cellular uptake without any obvious cytotoxicity and exhibited excellent radiosensitization.

Molecular dynamics and pharmacophore modelling studies of different subtype (ALK and EGFR (T790M)) inhibitors in NSCLC

Extensively validated 3D pharmacophore models for ALK (anaplastic lymphoma kinase) and EGFR (T790M) (epithelial growth factor receptor with acquired secondary mutation) were developed. The pharmacophore model for ALK (r² = 0.96, q² = 0.692) suggested that two hydrogen bond acceptors and three hydrophobic groups arranged in 3-D space are essential for the binding affinity of ALK inhibitors. Similarly, the pharmacophore model for EGFR (T790M) (r² = 0.92, q² = 0.72) suggested that the presence of a hydrogen bond acceptor, two hydrogen bond donors and a hydrophobic group plays vital role in binding of an inhibitor of EGFR (T790M). These pharmacophore models allowed searches for novel ALK and EGFR (T790M) dual inhibitors from multiconformer 3D databases (Asinex, Chembridge and Maybridge). Finally, the eight best hits were selected for molecular dynamics simulation, to study the stability of their complexes with both proteins and final binding orientations of these molecules. After molecular dynamics simulations, one hit has been predicted to possess good binding affinity for both ALK and EGFR (T790M), which can be further investigated for its experimental in-vitro/in-vivo activities.