64 research outputs found
Plasma peptidome profiling of acute hepatitis E patients by MALDI-TOF/TOF
Background Hepatitis E is endemic to resource-poor regions, where it manifests as sporadic cases and large waterborne outbreaks. The disease severity ranges from acute self-limited hepatitis with low mortality to fulminant hepatic failure with high mortality. It is believed that the host response plays an important role in determining the progression and outcome of this disease. We profiled the plasma peptidome from hepatitis E patients to discover suitable biomarkers and understand disease pathogenesis. Results The peptidome (< 10 kDa) fraction of plasma was enriched and analyzed by mass spectrometry. A comparative analysis of the peptide pattern of hepatitis E patients versus healthy controls was performed using ClinPro Tools. We generated a peptide profile that could be used for selective identification of hepatitis E cases. We have identified five potential biomarker peaks with m/z values of 9288.6, 7763.6, 4961.5, 1060.572 and 2365.139 that can be used to reliably differentiate between hepatitis E patients and controls with areas under the receiver operating characteristic curve (AUROC) values of 1.00, 0.954, 0.989, 0.960 and 0.829 respectively. A number of proteins involved in innate immunity were identified to be differentially present in the plasma of patients compared to healthy controls. Conclusions Besides the utility of this approach for biomarker discovery, identification of changes in endogenous peptides in hepatitis E patient plasma has increased our understanding of disease pathogenesis. We have identified peptides in plasma that can reliably distinguish hepatitis E patients from healthy controls. Results from this and an earlier proteomics study are discussed
The Critical Role of N- and C-Terminal Contact in Protein Stability and Folding of a Family 10 Xylanase under Extreme Conditions
Stabilization strategies adopted by proteins under extreme conditions are very complex and involve various kinds of interactions. Recent studies have shown that a large proportion of proteins have their N- and C-terminal elements in close contact and suggested they play a role in protein folding and stability. However, the biological significance of this contact remains elusive.In the present study, we investigate the role of N- and C-terminal residue interaction using a family 10 xylanase (BSX) with a TIM-barrel structure that shows stability under high temperature, alkali pH, and protease and SDS treatment. Based on crystal structure, an aromatic cluster was identified that involves Phe4, Trp6 and Tyr343 holding the N- and C-terminus together; this is a unique and important feature of this protein that might be crucial for folding and stability under poly-extreme conditions. folding and activity. Alanine substitution with Phe4, Trp6 and Tyr343 drastically decreased stability under all parameters studied. Importantly, substitution of Phe4 with Trp increased stability in SDS treatment. Mass spectrometry results of limited proteolysis further demonstrated that the Arg344 residue is highly susceptible to trypsin digestion in sensitive mutants such as ΔF4, W6A and Y343A, suggesting again that disruption of the Phe4-Trp6-Tyr343 (F-W-Y) cluster destabilizes the N- and C-terminal interaction. Our results underscore the importance of N- and C-terminal contact through aromatic interactions in protein folding and stability under extreme conditions, and these results may be useful to improve the stability of other proteins under suboptimal conditions
A Search for Technosignatures Around 11,680 Stars with the Green Bank Telescope at 1.15-1.73 GHz
We conducted a search for narrowband radio signals over four observing
sessions in 2020-2023 with the L-band receiver (1.15-1.73 GHz) of the 100 m
diameter Green Bank Telescope. We pointed the telescope in the directions of 62
TESS Objects of Interest, capturing radio emissions from a total of ~11,680
stars and planetary systems in the ~9 arcminute beam of the telescope. All
detections were either automatically rejected or visually inspected and
confirmed to be of anthropogenic nature. In this work, we also quantified the
end-to-end efficiency of radio SETI pipelines with a signal injection and
recovery analysis. The UCLA SETI pipeline recovers 94.0% of the injected
signals over the usable frequency range of the receiver and 98.7% of the
injections when regions of dense RFI are excluded. In another pipeline that
uses incoherent sums of 51 consecutive spectra, the recovery rate is ~15 times
smaller at ~6%. The pipeline efficiency affects calculations of transmitter
prevalence and SETI search volume. Accordingly, we developed an improved Drake
Figure of Merit and a formalism to place upper limits on transmitter prevalence
that take the pipeline efficiency and transmitter duty cycle into account.
Based on our observations, we can state at the 95% confidence level that fewer
than 6.6% of stars within 100 pc host a transmitter that is detectable in our
search (EIRP > 1e13 W). For stars within 20,000 ly, the fraction of stars with
detectable transmitters (EIRP > 5e16 W) is at most 3e-4. Finally, we showed
that the UCLA SETI pipeline natively detects the signals detected with AI
techniques by Ma et al. (2023).Comment: 22 pages, 9 figures, submitted to AJ, revise
Protocol of an individual participant data meta-analysis to quantify the impact of high ambient temperatures on maternal and child health in Africa (HE 2 AT IPD)
Introduction:
Globally, recognition is growing of the harmful impacts of high ambient temperatures (heat) on health in pregnant women and children. There remain, however, major evidence gaps on the extent to which heat increases the risks for adverse health outcomes, and how this varies between settings. Evidence gaps are especially large in Africa. We will conduct an individual participant data (IPD) meta-analysis to quantify the impacts of heat on maternal and child health in sub-Saharan Africa. A detailed understanding and quantification of linkages between heat, and maternal and child health is essential for developing solutions to this critical research and policy area.
Methods and analysis:
We will use IPD from existing, large, longitudinal trial and cohort studies, on pregnant women and children from sub-Saharan Africa. We will systematically identify eligible studies through a mapping review, searching data repositories, and suggestions from experts. IPD will be acquired from data repositories, or through collaboration with data providers. Existing satellite imagery, climate reanalysis data, and station-based weather observations will be used to quantify weather and environmental exposures. IPD will be recoded and harmonised before being linked with climate, environmental, and socioeconomic data by location and time. Adopting a one-stage and two-stage meta-analysis method, analytical models such as time-to-event analysis, generalised additive models, and machine learning approaches will be employed to quantify associations between exposure to heat and adverse maternal and child health outcomes.
Ethics and dissemination:
The study has been approved by ethics committees. There is minimal risk to study participants. Participant privacy is protected through the anonymisation of data for analysis, secure data transfer and restricted access. Findings will be disseminated through conferences, journal publications, related policy and research fora, and data may be shared in accordance with data sharing policies of the National Institutes of Health. PROSPERO registration number: CRD42022346068
Glyoxalase I from Brassica juncea: molecular cloning, regulation and its over-expression confer tolerance in transgenic tobacco under stress
Despite its ubiquitous presence, the role of glyoxalase I has not been well investigated in plants. In order to find out its physiological functions, we have cloned and characterized a cDNA from Brassica juncea encoding glyoxalase I (Gly I) and made transgenic tobacco plants harbouring Gly I in both sense and antisense orientation. The transgenic nature of the plants was confirmed by Southern blotting, and the estimated number of genes inserted ranged from one to six. The transcript and protein levels of glyoxalase I were also monitored in transgenic plants. The expression of glyoxalase I in B. juncea was upregulated in response to salt, water and heavy metal stresses. In response to a high concentration of salt, the transcript level averaged threefold higher in 72 h, and an increase in the protein was also seen by immunoblotting. The transgenic plants over-expressing glyoxalase I showed significant tolerance to methylglyoxal and high salt, as tested in detached leaf disc senescence assay. A comparison of plants expressing high and low levels of glyoxalase I showed that the tolerance to different salt concentrations was correlated with the degree of glyoxalase I expression. Our results suggest an important role of glyoxalase I in conferring tolerance to plants under stress conditions
Single-crystal film piezoelectric sensors, actuators and energy harvesters with interdigitated electrodes
In this paper, the design and the fabrication of novel devices using single crystal lead zinc niobate-lead titanate (1 - x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-PT) and lead magnesium niobate-lead titanate (1 - x)Pb(Mg1/3Nb2/3)O3- xPbTiO3 (PMN-PT) are presented. Piezoelectric biosensors using PZN-PT and PMN-PT are discussed. These single-crystal sensors improve on the existing detection sensitivity of quartz or silicon based devices. The biosensors can be miniaturized through the fabrication of freestanding single crystal films and patterning by ion milling and argon-ion laser etching. A smart cantilever structure using PZN-PT and PMN-PT is also presented. This device possesses both sensing and actuation capabilities, in a single monomorph configuration. Finally, a PMN-PT energy harvester with interdigitated electrodes is demonstrated. The device converts mechanical vibration energy into electrical energy through the piezoelectric effect. A simple PMN-PT energy harvesting beam is integrated into an electrical energy storage device
Single-crystal relaxor ferroelectric piezoactuators with interdigitated electrodes
We report on the fabrication and performance of (1-x) Pb(Zn 1/3Nb 2/3)O 3-xPbTiO 3 (PZN-PT) single-crystal relaxor piezoactuators with interdigitated electrodes patterned on a single surface. An electric field gradient across the sample thickness induces a differential contraction between opposite faces, and it is responsible for the actuation. The samples are poled by energizing the electrodes at 100°C and cooling in a field. Calculations of the piezoelectric response based on a periodically modulated dipolar field yield good agreement with experiment. Discrepancies with the model are ascribed to multidomain formation in the ferroelectric sample as a result of field reversals in the applied electric field along the sample length
Transgenic tobacco expressing Entamoeba histolytica calcium binding protein exhibits enhanced growth and tolerance to salt stress
Calcium has been recognized as an important signal in many abiotic stresses. Our earlier work indicated the presence of homologues of a novel calcium binding protein from Entamoeba histolytica (EhCaBP) and its binding proteins with kinase activity in different plants. In this paper, we demonstrate the transfer of EhCaBP cDNA into tobacco via Agrobacterium mediated transformation. The transgenic plants expressing EhCaBP proteins were identified using western blots and immuno-precipitation of the labeled EhCaBP protein. The seeds obtained from the transgenic plants exhibited enhanced rate of germination and increased growth and had 20-37% more dry weight in 3 weeks old seedlings compared to wild type controls. The seeds of transgenic plants were also able to germinate and grow on 200 mM NaCl. The dry weight of different EhCaBP expressing plants maintained on NaCl was 55-100% more as compared to wild type plants. The increased growth and tolerance to salinity conditions were correlated with the expression of EhCaBP protein in the transgenic plants
Destructive adsorption of methyl parathion over nanocrystalline MgO
251-255Destructive adsorption of methyl parathion
(MP) has been investigated over few transition metal oxides and alkali earth metal
oxides. Performance of alkaline earth ox ides have been found to be better than
transition metal oxides and best performance has been shown by aerogel method prepared
nanocrystalline AP-MgO. The AP-MgO powder has been
characterized by XRD, AFM and BET
surface area measurements. Destructive adsorption of MP over AP-MgO has been compared
with that of activated carbon. Both are found to adsorb methyl parathion effectively.
An IR investigation of the surface of treated AP-MgO and activated carbon reveals
that activated carbon adsorbs methyl parathion as such in the
molecular form and AP-MgO adsorbs it destructively
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