Screening of streptococcus pneumoniae ABC transporters for their role in virulence and investigation of their lipoprotein components as vaccine candidates

Streptococcus pneumoniae causes life-threatening invasive diseases in children and older adults. Although effective at reducing the incidence of disease, the two currently available vaccines against S. pneumoniae have significant limitations that a vaccine based on protein antigens may overcome. For this thesis I have investigated the role of S. pneumoniae ABC transporters during infection, and have assessed as potential vaccine candidates the lipoprotein components of two ABC transporters. Eleven ABC transporters were chosen for investigation of their role during infection, and disruption mutant strains were successfully constructed for 9 of these. Two mutant strains disrupting the Sp0148-52 and Sp0749-53 ABC transporters, which BLAST searches suggest have methionine and branched chain amino acids (BCAAs) as substrates respectively, were markedly attenuated in systemic and pulmonary mice models of virulence. Western blotting and PCR confirmed that the lipoprotein components of these ABC transporters, Sp0149 and Sp0749, are present in all the S. pneumoniae strains investigated and are membrane-localised. Radioactive and fluorescence ligand binding experiments showed the Sp0749 lipoprotein specifically bound to BCAAs, confirming Sp0749-53 encodes a BCAA ABC transporter. Vaccination of mice with His6-Sp0149 and His6-Sp0749 induced specific IgG which was able to increase complement activity against and phagocytosis of S. pneumoniae. Intranasal immunisation of mice with His6-Sp0749 and His6-PiaA, affected the immune response to subsequent intranasal challenge with S. pneumoniae and increased lung inflammation upon subsequent S. pneumoniae intranasal challenge. However, both intraperitoneal and intranasal immunisation of mice with His6-Sp0149 and His6-Sp0749 resulted in only minor degrees of protection against S. pneumoniae septicaemia and pneumonia respectively. These results demonstrate that the S. pneumoniae BCAA ABC transporter is required for the full virulence, and its lipoprotein component can elicit immune responses against invasive S. pneumoniae that although weakly protective could contribute towards a multivalent vaccine

Analysis of Damping in Soil as Applied to Machine Foundations

The parameters needed for the design of machine foundations are usually evaluated from the model block resonance test conducted at a given site. Sometimes it may not be possible to attain complete resonance and the test results may be limited to the ascending part of the response. In this paper the possible effect of damping on the values of the design parameters evaluated from the ascending part of response is examined and the nature of damping which gives realistic values of design parameters is presented

Load Settlement Characteristics and Bearing Capacity of Clays Under Transient Load

The investigation presented here utilizes finite element technique coupled with Galerikins weighted residual process to predict the settlement of footing resting on the surface of clays and subjected to transient load. The predicted quantities have been compared with the experimental observations of model footing tests. The influence of fundamental natural period of soil and foundation system on the settlement and bearing capacity of footing has been brought out

Role of the newly synthesized brightener in modification of surface properties of Zn-Ni alloy electrodeposited on steel substrate

In the present study, a new brightener was synthesized by condensation of salicylaldehyde and cysteine hydrochloride (SC). To examine the influence of SC on the nucleation mechanism of Zn-Ni alloy, electrodeposition, cyclic voltammetric and chronoamperometric studies were carried out. The model of Schariffker and Hills was used to analyze current transients which explained the electrocrystallization process of Zn-Ni alloy. It is revealed that Zn-Ni electrocrystallization process in presence of SC is regulated by instantaneous nucleation mechanism. The corrosion studies were done for the bright and dull zinc-nickel alloy coatings in 3.5 wt.% NaCl solution, using potentiodynamic polarization and electro­chemical impedance spectroscopic techniques. The phase structure, surface morphology and brightness of the deposit were characterized by means of X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and reflectance studies. These studies revealed the role of SC in producing a bright Zn-Ni alloy coating on mild steel substrate and also showed its improved corrosion resistant nature

Evaluation of wound healing activity of ethanolic extract of Azadirachta Indica leaves on incision and excision wound models in Wister albino rats

Background: Wound healing is complex cellular and biochemical cascade that lead to restitution of integrity and function. Recently, the traditional use of plants for wound healing has received attention by the scientific community, as traditional medicine is a source of less expensive, comprehensive medical care, especially in developing countries. Azadirachta indica (Neem) is well-known in India, as one of the most versatile medicinal plants having a wide spectrum of biological activity. Hence, this study was undertaken to evaluate the wound healing activity of the ethanolic extract of A. indica leaf in the experimentally-induced wound in rats.Methods: The healing effect produced by A. indica extract was assessed by the rate of wound contraction histopathology and skin breaking strength by using excision wound model and incision wound model in Wister albino rats. This was compared with control (soft white paraffin) and standard (1% w/w framycetin sulfate ointment). The results have been analyzed by calculating the mean values, standard deviation and compared by using student t-test.Results: The ethanol extract of leaves of A. indica significantly promoted the wound healing activity in both excision and incision wound models.Conclusion: The study revealed promising wound healing activity of ethanolic extract of A. indica and provides a scientific rationale for the traditional use in the management of wounds

Adverse drug reactions due to cancer chemotherapy in a tertiary care hospital in south Karnataka: a prospective observational study

Background: Cancer is a multi-cellular disease which can arise from any cell type and organs. Adverse drug reactions (ADR) are undesirable consequence of cancer chemotherapeutic drugs. A great importance has to be given for their assessment, detection, monitoring, reporting and preventing these ADR for the beneficial effects of the patients. So the present study was undertaken for the purpose of detecting and quantifying those adverse reactions which is of some importance in therapeutic setting.Methods: A prospective observational study conducted in chemotherapy ward, male and female patients of any age receiving cancer chemotherapy and presenting with ADR’s in duration of 3 months.Results: 160 patients were observed. Out of 160 patients 123 presented with ADR’s. Most common ADR’s were loss of appetite (67.6), diarrhea (61.8%), vomiting (21.5%), nausea (17.7%), anemia (24.7%). Cisplatin, paclitaxel, oxaliplatin, doxorubicin, gefitinib are common drugs causing ADR’s.Conclusions: Cancer chemotherapeutic drugs are associated with various adverse reactions. This study shows the importance of active monitoring of these reactions and measures to prevent their effects early in the treatment of cancer

Evaluation of pharmacotherapy in neonatal and pediatric intensive care unit of a south Indian tertiary care hospital: a prospective observational study

Background: Evaluating the pharmacotherapy is essential at neonatal intensive care unit (NICU) and pediatric intensive care unit (PICU) to identify and understand pattern and variability in drug use in polypharmacy, also to promote interventions that will improve patient outcomes.Methods: In our study, we audited pharmacotherapy of 300 neonates and 100 pediatric patients admitted to NICU and PICU from November 2018 to February 2019. WHO-CORE prescribing indicators, WHO-ATC system and WHO-ICD 10th version was used to evaluate pharmacotherapy and to understand the pattern and extent of medication use and to systematically classify drugs and diseases respectively.Results: A total of 1207 medications containing 34 unique active ingredients were prescribed for 300 neonates with an average of 4.02 (±2.0) drugs per neonate admitted to NICU and the most prescribed drugs were anti-infectives for systemic use 799. A total of 976 medications containing 69 unique active ingredients were prescribed with an average of 9.76 (±3.81) per pediatric patients admitted to PICU with anti-infectives for systemic use 331 tops the list. More than 75% of drugs was prescribed in generic name with 98% constant availability of key drugs at intensive care unit.Conclusions: This study substantiates the need for reinforcement of institutional antibiotic policies as antibiotics are widely prescribed and there is an increase trend of antibiotic resistance at critical care unit, assessment of WHO core prescribing indicators are reflective of quality care revealing the awareness about strict monitoring of pharmacotherapy

Toward Continuous Monitoring of Breath Biochemistry: A Paper-Based Wearable Sensor for Real-Time Hydrogen Peroxide Measurement in Simulated Breath

Exhaled breath contains a large amount of biochemical and physiological information concerning one’s health and provides an alternative route to noninvasive medical diagnosis of diseases. In the case of lung diseases, hydrogen peroxide (H2O2) is an important biomarker associated with asthma, chronic obstructive pulmonary disease, and lung cancer and can be detected in exhaled breath. The current method of breath analysis involves condensation of exhaled breath, is not continuous or real time, and requires two separate and bulky devices, complicating the periodic or long-term monitoring of a patient. We report the first disposable paper-based electrochemical wearable sensor that can monitor exhaled H2O2 in artificial breath calibration-free and continuously, in real time, and can be integrated into a commercial respiratory mask for on-site testing of exhaled breath. To improve precision for sensing H2O2, we perform differential electrochemical measurement by amperometry in which screen-printed Prussian Blue-mediated and nonmediated carbon electrodes are used for differential analysis. We were able to measure H2O2 in simulated breath in a concentration-dependent manner in real time, confirming its functionality. This proposed system is versatile, and by modifying the chemistry of the sensing electrodes, our method of differential sensing can be extended to continuous monitoring of other analytes in exhaled breath

Chemical interaction, interfacial effect and the microstructural characterization of the induced zinc–aluminum–Solanum tuberosum in chloride solution on mild steel

In this study, we report the effect of Solanum tuberosum (ST) as a strong additive on the morphological interaction, wear, and hardness properties of electroplated zinc coating in chloride bath solutions. The structural and the mechanical behavior of the Zn–Al–ST coating were studied and compared with the properties of Zn coatings. Characterization of the electrodeposited coatings were carried out using scanning electron microscopy, energy dispersive spectrometer, AFM, and X-ray diffraction techniques. The adhesion between the coatings and substrate was examined mechanically using hardness and wear techniques. From the results, amorphous Zn–Al–ST coatings were effectively obtained by electrodeposition using direct current. The coating morphology was revealed to be reliant on the bath composition containing strong leveling additives. From all indications, ST content contribute to a strong interfacial surface effect leading to crack-free and better morphology, good hardness properties, and improved wear resistance due to the precipitation of Zn2Si and Zn7Al2Si3. Hence, addition of ST is beneficial for the structural strengthening, hardness, and wear resistance properties of such coatings

Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo

Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt), deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection