| 1. |
- Jakubauskas, Dainius, et al.
(författare)
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Toward reliable low-density lipoprotein ultrastructure prediction in clinical conditions : A small-angle X-ray scattering study on individuals with normal and high triglyceride serum levels
- 2021
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Ingår i: Nanomedicine. - : Elsevier. - 1549-9634 .- 1549-9642. ; 31, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Atherosclerosis is the main killer in the west and therefore a major health challenge today. Total serum cholesterol and lipoprotein concentrations, used as clinical markers, fail to predict the majority of cases, especially between the risk scale extremes, due to the high complexity in lipoprotein structure and composition. In particular, low-density lipoprotein (LDL) plays a key role in atherosclerosis development, with LDL size being a parameter considered for determining the risk for cardiovascular diseases. Determining LDL size and structural parameters is challenging to address experimentally under physiological-like conditions. This article describes the biochemistry and ultrastructure of normolipidemic and hypertriglyceridemic LDL fractions and subfractions using small-angle X-ray scattering. Our results conclude that LDL particles of hypertriglyceridemic compared to healthy individuals 1) have lower LDL core melting temperature, 2) have lower cholesteryl ester ordering in their core, 3) are smaller, rounder and more spherical below melting temperature, and 4) their protein-containing shell is thinner above melting temperature.
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| 2. |
- Jakubauskas, Dainius, et al.
(författare)
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Ultrastructural modeling of small angle scattering from photosynthetic membranes
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The last decade has seen a range of studies using non-invasive neutron and X-ray techniques to probe the ultrastructure of a variety of photosynthetic membrane systems. A common denominator in this work is the lack of an explicitly formulated underlying structural model, ultimately leading to ambiguity in the data interpretation. Here we formulate and implement a full mathematical model of the scattering from a stacked double bilayer membrane system taking instrumental resolution and polydispersity into account. We validate our model by direct simulation of scattering patterns from 3D structural models. Most importantly, we demonstrate that the full scattering curves from three structurally typical cyanobacterial thylakoid membrane systems measured in vivo can all be described within this framework. The model provides realistic estimates of key structural parameters in the thylakoid membrane, in particular the overall stacking distance and how this is divided between membranes, lumen and cytoplasmic liquid. Finally, from fitted scattering length densities it becomes clear that the protein content in the inner lumen has to be lower than in the outer cytoplasmic liquid and we extract the first quantitative measure of the luminal protein content in a living cyanobacteria.
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| 3. |
- Kalimuthu, Palraj, et al.
(författare)
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Battery-free radio frequency wireless sensor for bacteria based on their degradation of gelatin-fatty acid composite films
- 2021
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 381
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Tidskriftsartikel (refereegranskat)abstract
- Continuous and automated bacteria detection is pivotal for a myriad of biomedical, food safety and envi-ronmental applications. This work presents the fabrication of a prototype of a passive (battery-free) radio frequency sensor for wireless detection of bacteria. The sensing mechanism is based on the bacterial-induced (proteases and peptidases) degradation of glutaraldehyde (GTA) cross-linked gelatin-caprylic acid (CA) composite film. Proteolytic degradation of the film resulted in a decrease of its resistivity, a quan-tity that could be wirelessly monitored by coupling the film to a radio-frequency antenna (an inductor-capacitor resonator) and monitoring the frequency for which the transferred power between this antenna and another antenna connected to a Vector Network Analyzer (VNA) was maximized. We experimen-tally proved this concept by monitoring E.coli bacteria in aqueous medium and detected at 18.0 +/- 2.8 h, 23.5 +/- 0.7 h, 27.0 +/- 2.8 h, 40.5 +/- 3.5 h, 45.5 +/- 0.7 h for the initial E.coli concentration of 3.2 +/- 10(8) , 6.8 +/- 10(7) , 2.3 +/- 10(6) , 4.3 +/- 10(5) , and 3.6 +/- 10(4) CFU/mL, respectively. Further, the E.coli induced degrada-tion of the composite film was investigated by evaluating the thickness of the film by optical microscopy as well as morphology by scanning electron microscopy techniques. (C) 2021 Published by Elsevier Ltd.
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| 4. |
- Thirabowonkitphithan, Pannawich, et al.
(författare)
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Electrogenicity of microbial biofilms of medically relevant microorganisms : potentiometric, amperometric and wireless detection.
- 2024
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 246
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Tidskriftsartikel (refereegranskat)abstract
- Since the progression of biofilm formation is related to the success of infection treatment, detecting microbial biofilms is of great interest. Biofilms of Gram-positive Staphylococcus aureus and Streptococcus gordonii bacteria, Gram-negative Pseudomonas aeruginosa and Escherichia coli bacteria, and Candida albicans yeast were examined using potentiometric, amperometric, and wireless readout modes in this study. As a biofilm formed, the open circuit potential (OCP) of biofilm hosting electrode (bioanode) became increasingly negative. Depending on the microorganism, the OCP ranged from −70 to −250 mV. The co-culture generated the most negative OCP (−300 mV vs Ag/AgCl), while the single-species biofilm formed by E. coli developed the least negative (−70 mV). The OCP of a fungal biofilm formed by C. albicans was −100 mV. The difference in electrode currents generated by biofilms was more pronounced. The current density of the S. aureus biofilm was 0.9‧10−7 A cm−2, while the value of the P. aeruginosa biofilm was 1.3‧10−6 A cm−2. Importantly, a biofilm formed by a co-culture of S. aureus and P. aeruginosa had a slightly higher negative OCP value and current density than the most electrogenic P. aeruginosa single-species biofilm. We present evidence that bacteria can share redox mediators found in multi-species biofilms. This synergy, enabling higher current and OCP values of multi-species biofilm hosting electrodes, could be beneficial for electrochemical detection of infectious biofilms in clinics. We demonstrate that the electrogenic biofilm can provide basis to construct novel wireless, chip-free, and battery-free biofilm detection method.
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