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Point-of-care testing (POCT) devices are becoming increasingly popular in the medical community as an alternative to conventional laboratory testing, especially for home treatments or other forms of outpatient care. Multiple-use chemical sensors with minimal requirements for disposables are among the most practical and cost-effective POC diagnostic instruments, especially in managing chronic conditions. An affordable, simple, and easy-to-use optical sensor based on fast protein liquid chromatography with direct UV absorption detection was developed for the rapid determination of the total protein concentration in effluent peritoneal dialysate and for the assessment of protein losses in end-stage renal disease (ESRD) patients on constant ambulatory peritoneal dialysis (CAPD). The sensor employs non-disposable PD-10 desalting columns for the separation of molecules with different molecular weights and a deep UV LED (maximum at 285 nm) as a light source for optical detection. The analytic procedure is relatively simple, takes 10–15 min, and potentially can be performed by patients themselves or nursing staff without laboratory training. Preliminary clinical trials on a group of 23 patients on CAPD revealed a good concordance between the protein concentrations in dialysate samples measured with the sensor and an automated biochemical analyzer; the mean relative error was about 10%, which is comparable with routine clinical laboratory methods.

Increased oxidative stress is associated with type-2 diabetes and related cardiovascular diseases, but oxidative modification of LDL has been partially characterized. Our aim was to compare the lipid and fatty acid composition as well as the redox status of LDL from diabetic patients and healthy subjects. First, to ensure that isolation of LDL by sequential ultracentrifugation did not result in lipid modifications, lipid composition and peroxide content were determined in LDL isolated either by ultracentrifugation or fast-protein liquid chromatography. Both methods resulted in similar concentrations of lipids, fatty acids, hydroxy-octadecadienoic acid (HODE) and malondialdehyde (MDA). Then, LDLs were isolated by ultracentrifugation from eight type-2 diabetic patients and eight control subjects. Compared to control LDL, diabetic LDL contained decreased cholesteryl esters and increased triglyceride concentrations. Ethanolamine plasmalogens decreased by 49%. Proportions of linoleic acid decreased in all lipid classes, while proportions of arachidonic acid increased in cholesteryl esters. Total HODE concentrations increased by 56%, 12- and 15-hydroxy-eicosatetraenoic acid by 161 and 86%, respectively, and MDA levels increased by twofold. α-Tocopherol concentrations, expressed relative to triglycerides, were lower in LDL from patients compared to controls, while γ-tocopherol did not differ. Overall, LDL from type-2 diabetic patients displayed increased oxidative stress. Determination of hydroxylated fatty acids and ethanolamine plasmalogen depletion could be especially relevant in diabetes.

Host proteins from Nicotiana benthamiana can remain in the recombinant biologic products after undergoing multiple steps of purification. These plant protein impurities may induce immunogenicity upon use. Therefore, controlling and monitoring host cell proteins is necessary throughout the process of recombinant protein production. Liquid chromatography-mass spectrometry (LC-MS) has been successfully used to characterize protein species down to nanogram levels in various types of samples. In this study, LC-MS was applied to detect N. benthamiana plant proteins in plant-produced pembrolizumab anti-cancer antibody. Two types of purification techniques, gravity flow with manually packed column and automated system with prepacked column, were studied. After purification, the protein products were primarily assessed with SDS-PAGE and Western blot analyses and further examined with LC-MS to confirm protein identity and investigate plant protein contaminations. The pembrolizumab sequence was confirmed with more than 89% coverage. A higher number of host plant proteins were detected in the protein samples purified with gravity flow column. Luminal-binding protein 5 and ribulose bisphosphate carboxylase (RuBisCO) enzyme were predominant host plant proteins detected. Luminal-binding protein 5 was observed in the products purified with both purification methods. It was likely bound to pembrolizumab antibody and co-eluted into eluate fraction as its sequence is similar to binding immunoglobulin protein (BiP). RuBisCO enzyme was detected in the samples purified with gravity flow only. Its presence was likely due to incomplete wash by gravity flow chromatography. In summary, this study provided an important clue for plant proteins that could be contaminated in plant-produced products and suggested that second column chromatography is required to enhance purification efficiency.

Background Green fluorescent protein (GFP) is a valuable macromolecule widely utilized in biomedical diagnostics and diverse biotechnological applications due to its low toxicity and intrinsic fluorescence, which does not require exogenous substrates or cofactors. Nevertheless, the conventional Aequorea victoria –derived GFP exhibits limitations, including relatively low brightness and restricted applicability under low-oxygen conditions. Consequently, there is increasing interest in identifying alternative and less explored microbial sources of GFP, particularly from marine environment. Results In the current study, eleven fluorescent bacteria were isolated from different anatomical parts of squid collected from Miami Beach (Alexandria, Egypt) and from seawater sample from Atubia island (Safaga, Egypt). Among the three isolation media evaluated, Sea Water Complete agar medium (SWC) supported the highest recovery of fluorescent bacteria. Fluorescence-based primary and secondary screening identified isolate E2 as the most efficient GFP producer. It was identified phenotypically using the VITEK ® 2 automated system and genotypically using 16 S rRNA studies as Pseudomonas gessardii with 99.34% similarity. Sequences of the 16 S rRNA gene were deposited in the GenBank as OQ285875. Optimization of environmental condition using a one-factor-at-a-time approach revealed the maximum GFP production was achieved after 30 h of incubation at 25 °C and pH 7.5 under static conditions (0 rpm). These optimized parameter enhanced the fluorescence intensity of GFP by 1.51-fold compared to the basal medium. Subsequent purification using an aqueous two-phase system and fast protein liquid chromatography successfully recovered GFP with a high purity of 96.3%. Conclusion Overall, the current study identifies Pseudomonas gessardii E2 strain as a novel marine-derived source of high-quality pure GFP and establishes an effective strategy for its production and purification. The findings provide a promising foundation for the potential application of this GFP in bioimaging, biosensing, and fluorescence-based reporter systems, including applications in oxygen-limited environments.

Extracellular vesicles (EVs) are valuable targets for liquid biopsy. However, attempts to introduce EV‐based biomarkers into clinical practice have not been successful to the extent expected. One of the reasons for this failure is the lack of reliable methods for EV baseline purification from complex biofluids, such as cell‐free plasma or serum. Because available one‐step approaches for EV isolation are insufficient to purify EVs, the majority of studies on clinical samples were performed either on a mixture of EVs and lipoproteins, whilst the real number of EVs and their individual specific biomarker content remained elusive, or on a low number of samples of sufficient volume to allow elaborate 2‐step EV separation by size and density, resulting in a high purity but utmost low recovery. Here we introduce Fast Protein Liquid Chromatography (FPLC) using Superose 6 as a matrix to obtain small EVs from biofluids that are almost free of soluble proteins and lipoproteins. Along with the estimation of a realistic number of small EVs in human samples, we show temporal resolution of the effect of the duration of postprandial phase on the proportion of lipoproteins in purified EVs, suggesting acceptable time frames additionally to the recommendation to use fasting samples for human studies. Furthermore, we assessed a potential value of pure EVs for liquid biopsy, exemplarily examining EV‐ and tumour‐biomarkers in pure FPLC‐derived fractions isolated from the serum of patients with pancreatic cancer. Consistent among different techniques, showed the presence of diseases‐associated biomarkers in pure EVs, supporting the feasibility of using single‐vesicle analysis for liquid biopsy.

Background The previous study investigated whether the functions of small, medium, and large high density lipoprotein (S/M/L-HDL) are correlated with protein changes in mice. Herein, the proteomic and functional analyses of high density lipoprotein (HDL) subclasses were performed in humans and rats. Methods After purifying S/M/L-HDL subclasses from healthy humans ( n  = 6) and rats ( n  = 3) using fast protein liquid chromatography (FPLC) with calcium silica hydrate (CSH) resin, the proteomic analysis by mass spectrometry was conducted, as well as the capacities of cholesterol efflux and antioxidation was measured. Results Of the 120 and 106 HDL proteins identified, 85 and 68 proteins were significantly changed in concentration among the S/M/L-HDL subclasses in humans and rats, respectively. Interestingly, it was found that the relatively abundant proteins in the small HDL (S-HDL) and large HDL (L-HDL) subclasses did not overlap, both in humans and in rats. Next, by searching for the biological functions of the relatively abundant proteins in the HDL subclasses via Gene Ontology, it was displayed that the relatively abundant proteins involved in lipid metabolism and antioxidation were enriched more in the medium HDL (M-HDL) subclass than in the S/L-HDL subclasses in humans, whereas in rats, the relatively abundant proteins associated with lipid metabolism and anti-oxidation were enriched in M/L-HDL and S/M-HDL, respectively. Finally, it was confirmed that M-HDL and L-HDL had the highest cholesterol efflux capacity among the three HDL subclasses in humans and rats, respectively; moreover, M-HDL exhibited higher antioxidative capacity than S-HDL in both humans and rats. Conclusions The S-HDL and L-HDL subclasses are likely to have different proteomic components during HDL maturation, and results from the proteomics-based comparison of the HDL subclasses may explain the associated differences in function.

Fast protein and metabolite liquid chromatography (FPLMC) was introduced years ago to enable the easy separation of high-molecular compounds such as proteins from small molecules and the identification of the low-molecular substances. In this paper, the method is applied for the rapid evaluation of freshness and monitoring the aging of animal meat and fish. A novel chromatographic sensor was developed with a deep UV LED-based photometric detection unit (255–265 nm), an original flow cuvette and registration scheme; the processing of a chromatogram with the sensor takes approximately 15 min. Strict isochronism between the elution of ATP metabolites, mainly hypoxanthine (Hx) and inosine monophosphate (IMP), and the time of maturation of meat or fish, was discovered. A new freshness index H* = [Hx]/[IMP] was introduced, which is proportional to the instrumental delay time in the FPMLC chromatograms: the H* index < 0.5 indicates the presence of inosine monophosphate (IMP) and the high quality of the meat or fish. Reasonably strong correlations were revealed between data obtained by FPMLC and total volatile basic nitrogen TVB-N (for fish) or volatile fatty acids VFA (for meat) content. Moreover, putative nucleotide salvage and an increase in the concentration of IMP were observed in fish after heat treatment using the FPMLC sensor and NMR technique.

Small ubiquitin-like modifier (SUMO) fusion technology is widely used in the production of heterologous proteins from prokaryotic system to aid in protein solubilization and refolding. Due to an extensive clinical application of human bone morphogenetic protein 2 (hBMP2) in bone augmentation, total RNA was isolated from human gingival tissue and mature gene was amplified through RT-PCR, cloned (pET21a), sequence analyzed, and submitted to GenBank (Accession no. KF250425). To obtain soluble expression, SUMO3 was tagged at the N-terminus of hBMP2 gene (pET21a/SUMO3-hBMP2), transferred in BL21 codon+, and ~ 40% soluble expression was obtained on induction with IPTG. The dimerized hBMP2 was confirmed with Western blot, native PAGE analysis, and purified by fast protein liquid chromatography with 0.5 M NaCl elution. The cleavage of SUMO3 tag from hBMP2 converted it to an insoluble form. Computational 3D structural analysis of the SUMO3-hBMP2 was performed and optimized by molecular dynamic simulation. Protein-protein interaction of SUMO3-hBMP2 with BMP2 receptor was carried out using HADDOCK and inferred stable interaction. The alkaline phosphatase assay of SUMO3-hBMP2 on C2C12 cells showed maximum 200-ng/ml dose-dependent activity. We conclude that SUMO3-tagged hBMP2 is more suited for generation of soluble form of the protein and addition of SUMO3 tag does not affect the functional activity of hBMP2.

AbstractThe cyanobacterial circadian clock is the most well-understood and simplest biological time-keeping system. Its oscillator consists of three proteins: KaiA, KaiB, and KaiC. When combined together in a test tube, the Kai proteins produce a free-running 24-h cycle of rhythmic auto-phosphorylation and auto-dephosphorylation. To generate a robust circadian rhythm of the in vitro reaction mixture, KaiC, the core oscillator protein, must be purified with an untraditional approach, since even the smallest amount of impurity can hinder its post-translational activities. Until recently, series of fast protein liquid chromatography (FPLC) columns (glutathione S-transferase (GST), anion exchange (Q), and desalting columns) have been used to purify the oscillator proteins, often requiring laborious elution processes. Although the common methodology has already been established, whether the purified KaiC can produce robust oscillations remains to be verified. Here we emphasize the significance of eliminating the Q step and lengthening the step of removing the non-specifically bound impurities on the GST column for generating a rhythmic KaiC phosphorylation in vitro. These findings demonstrate the potential for shortening the amount of time and effort it takes to purify proteins without compromising its quality.

In several studies, different antigenic preparations and diverse immunological tests were applied for serodiagnosis of Fasciola hepatica infections. Most of these preparations showed cross-reactivity with proteins of other parasites. Application of purified antigens might reduce these cross-reactivities. Here, we used fast protein liquid chromatography (FPLC)-fractionated extracts of F. hepatica excretory/secretory antigens (E/S Ags) for serodiagnosis of human and sheep fasciolosis. To develop an improved diagnostic method, we fractionated F. hepatica E/S Ags by anion exchange chromatography on a Sepharose CL-6B column and then tested the serodiagnostic values of the fractions. We used sera from F. hepatica-infected human and sheep as positive controls. Sera from patients with hydatidosis and strongyloidiasis were used for cross-reactivity studies. Enzyme-linked immunosorbent assays (ELISA) of the second FPLC peak, containing 20, 25, and 70 kDa proteins, discriminated between F. hepatica-infected and uninfected human and sheep samples. Fractionation of F. hepatica E/S Ags by FPLC is a fast and reproducible way of obtaining antigens useful for serodiagnosis of human and sheep fasciolosis with acceptable sensitivity and specificity.Graphical abstract [Images not available. See PDF.]ᅟ