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Journal of Ophthalmic & Vision Research 2023Animal models are necessary in understanding the pathogenesis of endophthalmitis and are also necessary to assist the development of new therapeutics for this...
PURPOSE
Animal models are necessary in understanding the pathogenesis of endophthalmitis and are also necessary to assist the development of new therapeutics for this sight-threatening ocular inflammation. Hamilton syringes are usually preferred to inject pathogens when performing experiments on test subjects, however, this method has technical and financial disadvantages. In this study, we report the findings and assess the related benefits of applying a novel low-cost intravitreal injection technique to initiate endophthalmitis in a mouse model while using the Eppendorf tip and a 26G needle.
METHODS
The 18-hr culture of clinical isolates of bacteria ( and ) and fungus ( and ) were resuspended to a final concentration of 10,000 colony forming units (CFU)/1 µL which were separately injected intravitreally into C57BL/6 mice (6-8 weeks) using a 0.1-2.5µL pipette attached to the modified Eppendorf tip with a 26G needle. The contralateral eye served as vehicle/uninjected control. Disease progression was determined by assessing the corneal haze, opacity, bacterial burden, and retinal histology of the eyes used in the model. Following euthanization, bacteria-infected mice were enucleated after 24 hr of the initial injection, and fungus-infected mice after 72 hr.
RESULTS
Of the 50 mice injected, the modified technique was successful in 48 mice. Two mice were excluded due to cataract formed by accidental injury to the lens. The experimental endophthalmitis mice model successfully mimicked the natural clinical course. Clinical assessment and histopathology confirmed the influx of inflammatory cells into the posterior segment of the eye along with dissolution of retinal architecture.
CONCLUSION
Our novel method of injection using a modified Eppendorf tip and 26G needle yielded a cost-effective mouse model of clinical endophthalmitis, resulting in reproducible infection for understanding various aspects of its pathobiology.
PubMed: 37600911
DOI: 10.18502/jovr.v18i3.13775 -
Analytical Methods : Advancing Methods... May 2024This study outlines the development and optimization of an analytical method using Disposable Pipette Extraction (DPX) followed by high performance liquid...
This study outlines the development and optimization of an analytical method using Disposable Pipette Extraction (DPX) followed by high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis to determine NAs in medicines. HPLC-MS analysis utilized a reversed-phase and positive mode electrospray ion source. DPX parameters were optimized through univariate and multivariate analyses, including extraction phase, desorption solvent, sample pH, equilibrium time, and extraction/desorption cycles. The optimized conditions included a C18 extraction phase, methanol desorption solvent, pH at 7, an equilibrium time of 30 seconds, 2 extraction cycles, and 5 desorption cycles. Considering this method, it was possible to achieve a sample preparation step for the analysis of NAs in medicines using a minimal amount of extraction phase, sample, and desorption solvent. Furthermore, the total extraction procedure enables the extraction of NAs in around 4 minutes with NA recovery up to 98%. Analytical performance demonstrated precision and accuracy below 15% and a quantification limit of 1 ng mL, meeting validation requirements set by regulations worldwide. Thus, the DPX/HPLC-MS technique offers a faster and cost-effective method for analyzing NAs in medicines compared to traditional approaches. Besides, this method reduces solvent consumption and residue generation, enhancing environmental sustainability according to green chemistry principles.
Topics: Chromatography, High Pressure Liquid; Nitrosamines; Limit of Detection; Mass Spectrometry; Reproducibility of Results; Solid Phase Extraction; Liquid Chromatography-Mass Spectrometry
PubMed: 38747210
DOI: 10.1039/d4ay00554f -
Scientific Reports Oct 2023In this study, our primary objective was to develop an effective analytical method for studying trypsin-digested peptides of two proteins commonly found in cow's milk:...
In this study, our primary objective was to develop an effective analytical method for studying trypsin-digested peptides of two proteins commonly found in cow's milk: β-casein (βCN) and β-lactoglobulin (βLG). To achieve this, we employed two distinct approaches: traditional in-gel protein digestion and protein digestion using immobilized enzyme microreactors (μ-IMER). Both methods utilized ZipTip pipette tips filled with C18 reverse phase media for sample concentration. The μ-IMER was fabricated through a multi-step process that included preconditioning the capillary, modifying its surface, synthesizing a monolithic support, and further surface modification. Its performance was evaluated under HPLC chromatography conditions using a small-molecule trypsin substrate (BAEE). Hydrolysates from both digestion methods were analyzed using MALDI-TOF MS. Our findings indicate that the μ-IMER method demonstrated superior sequence coverage for oxidized molecules in βCN (33 ± 1.5%) and βLG (65 ± 3%) compared to classical in-gel digestion (20 ± 2% for βCN; 49 ± 2% for βLG). The use of ZipTips further improved sequence coverage in both classical in-gel digestion (26 ± 1% for βCN; 60 ± 4% for βLG) and μ-IMER (41 ± 3% for βCN; 80 ± 5% for βLG). Additionally, phosphorylations were identified. For βCN, no phosphorylation was detected using classical digestion, but the use of ZipTips showed a value of 27 ± 4%. With μ-IMER and μ-IMER-ZipTip, the values increased to 30 ± 2% and 33 ± 1%, respectively. For βLG, the use of ZipTip enabled the detection of a higher percentage of modified peptides in both classical (79 ± 2%) and μ-IMER (79 ± 4%) digestions. By providing a comprehensive comparison of traditional in-gel digestion and μ-IMER methods, this study offers valuable insights into the advantages and limitations of each approach, particularly in the context of complex biological samples. The findings set a new benchmark in protein digestion and analysis, highlighting the potential of μ-IMER systems for enhanced sequence coverage and post-translational modification detection.
Topics: Enzymes, Immobilized; Caseins; Lactoglobulins; Trypsin; Peptides; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 37783762
DOI: 10.1038/s41598-023-43521-z -
Plant Disease Aug 2023Quinoa (Chenopodium quinoa Willd.) is a traditional food originally from the Andes Mountains in South America. It was first planted in China in 1987 and is grown in...
Quinoa (Chenopodium quinoa Willd.) is a traditional food originally from the Andes Mountains in South America. It was first planted in China in 1987 and is grown in Tibet, Gansu, and Qinghai provinces. In May 2021, 40% of 2-month-old quinoa plants in the 3.4 hm² experimental base of Qinghai University (36.7262° N, 101.7487° E) were found to have leaves with grey-brown subcircular spots (about 0.4 to 0.7 cm) with black dots (acervuli). Severely infected plants exhibited symptoms such as withered and stunted growth. The diseased-healthy junctions of infected leaves (0.5 cm) were cut out, disinfected with 3% NaClO for 1.5 min, washed three times with sterile water, dried, placed on water agar, and incubated at 25°C for 48 h. After sporulation was seen on the leaf surface, spore suspensions were prepared by placing conidia in sterile water using a pipette. Next, 200 μl of each spore suspension was spread on the surface of water agar and incubated at 25°C for 12 h. Single spores were selected under a stereomicroscope and cultured on potato dextrose agar (PDA) (Qi et al. 2022). The mycelium of two representative isolates (20DLMF-5-4-1 and 20DLMF-7-4-1) was grey-black with white edges and included a fluffy aerial mycelium. Conidia were unicellular, colorless, long ellipsoid or curved moon shaped, averaging 14.3 × 1.8 to 20.2 × 2.2 μm (n=100). The light brown appressoria were ovoid, averaging 8.5 × 5.2 to 7.7 × 4.1 μm (n=20). Spherical, dark brown acervuli were observed on the leaves, averaging 160 to 200 μm (n=20), and there were dark brown spiny bristles. The ITS, partial ACT, CHS, GAPDH and TUB2 genes were amplified from genomic DNA of the two isolates (Weir et al. 2012). Sequences were deposited in GenBank (accession no. OQ871595 to OQ871602 for ACT, CHS, GAPDH, and TUB2, and OQ860235 to OQ860236 for ITS) and showed over 99% identities with the corresponding sequences of C. spinaciae CBS125347 and CBS128.57 (Vu et al. 2019; Damm et al. 2009). Both isolates clustered with the type culture of C. spinaciae (CBS125347, CBS128.57), with 100% bootstrap support in the phylogenetic tree. Thus, according to the morphological and molecular characteristics, the two isolates were identified as C. spinaciae. Pathogenicity tests were conducted on 24 healthy, tender leaves of six 1-month-old quinoa plants, with three replicates (Yang et al. 2021). The leaves were gently scratched in 3-4 areas with a sterile needle. A conidial suspension (105 conidia/ml) of the two isolates was sprayed on these wounds. The control group was unscratched and sprayed with sterile water. The plants were incubated in a greenhouse at 25°C for 24 h in the dark and 7 days in the light. Tiny grey-brown spots appeared on day 3 (about 0.4 to 0.6 cm) and continued to enlarge until perforations and ruptures developed on day 7. Subsequently, acervuli were observed on the surface of the leaves. The control leaves remained healthy. Isolates were reisolated from the symptomatic leaves and they had the same morphological and molecular characteristics as the original isolates, confirming Koch's postulates. To our knowledge, this is the first report of C. spinaciae causing quinoa leaf anthracnose in China. C. spinaciae seriously affects the yield and quality of quinoa and has been previously reported to cause anthracnose of Vicia sativa in China (Wang et al. 2019). The results provide a basis for the study and control of quinoa leaf anthracnose.
PubMed: 37622274
DOI: 10.1094/PDIS-07-23-1285-PDN -
Journal of Mass Spectrometry and... Aug 2023Free thyroxine (FT4) measurement is one of the most requested tests in patient care for diagnosing and treating thyroid-related illnesses. Equilibrium dialysis (ED) is...
BACKGROUND
Free thyroxine (FT4) measurement is one of the most requested tests in patient care for diagnosing and treating thyroid-related illnesses. Equilibrium dialysis (ED) is considered the "gold standard" for FT4 measurement; however, several factors have a profound effect on the reliability of FT4 assays and require special consideration.
METHODS
In the current study, we focused on evaluating critical factors that could contribute to reporting errors, such as adsorption of thyroxine (T4) to labware surfaces, stability of serum samples, stock solutions, and calibrator storage conditions, as well as the solvents used to prepare T4 solutions.
RESULTS
The adsorption of T4 in ethanolic solutions and dialysates to labware surfaces can be reduced with the careful selection of pipette tips, test tubes, and 96-well plates. Adding pH modifiers to neat T4 solutions can improve its stability. FT4 in serum samples remains stable after exposure to four freeze-thaw cycles, 5 °C for 18-20 h, or -70 °C for a minimum of three years.
CONCLUSION
The presented study has demonstrated that the loss of analyte due to pre-analytical and analytical factors during operation of the FT4 reference measurement procedure (RMP) can be minimized by careful selection of all labware for sample preparation. It was found that the accuracy and imprecision of FT4 assays can be influenced by different types of dialysis devices, but acceptable alternatives to ED membranes were identified. This study demonstrates approaches to establish a FT4 method that is independent from specific suppliers and addresses critical pre-analytical and analytical factors important for FT4 measurements.
PubMed: 37449264
DOI: 10.1016/j.jmsacl.2023.06.001 -
Veterinary World Jan 2024The production of lignocellulosic biomass waste in the agricultural sector of Indonesia is quite high annually. Utilization of lignocellulosic biomass waste through...
BACKGROUND AND AIM
The production of lignocellulosic biomass waste in the agricultural sector of Indonesia is quite high annually. Utilization of lignocellulosic biomass waste through fermentation technology can be used as feed and biofuel. Fermentation technology requires the involvement of micro-organisms such as bacteria (lactic acid bacteria or LAB). LABs can be isolated from various sources, such as duck excreta. However, there have not been many reports of LAB from duck excreta. The present study aimed to characterize LAB enzymes isolated from duck excreta and obtain LAB enzymes with superior fermentation properties.
MATERIALS AND METHODS
A total of 11 LAB cultures obtained from duck excreta in Yogyakarta, Indonesia, were tested. Enzyme characterization of each LAB was performed using the API ZYM kit (BioMérieux, Marcy-I'Etoile, France). The bacterial cell suspension was dropped onto the API ZYM™ cupule using a pipette and incubated for 4 h at 37°C. After incubation, ZYM A and ZYM B were dripped onto the API ZYM cupule, and color changes were observed for approximately 10 s under a strong light source.
RESULTS
Esterase activity was moderate for all LABs. The activity of α-chymotrypsin, β-glucuronidase, α-fucosidase, and α-mannosidase was not observed in a total of 10 LAB. The phosphohydrolase and amino peptidase enzyme activity of seven LABs was strong. Only six LAB samples showed protease activity. The glycosyl hydrolase (GH) activity was observed in a total of 8 LAB, while the activity of 2 LAB was strong ( subsp. K5 and M4A).
CONCLUSION
A total of 2 LABs have superior properties. subsp. K5 and M4A have a high potential to be used in fermentation. They have the potential for further research, such as their effectiveness in fermentation, lignocellulose hydrolysis, feed additives, molecular characterization to detect specific enzymes, and their specific activities.
PubMed: 38406367
DOI: 10.14202/vetworld.2024.143-149 -
Longitudinal diffusion barriers imposed by myofilaments and mitochondria in murine cardiac myocytes.The Journal of General Physiology Oct 2023Using optical and electrical methods, we document that diffusion in the cytoplasm of BL6 murine cardiomyocytes becomes restricted >20-fold as molecular weight increases...
Using optical and electrical methods, we document that diffusion in the cytoplasm of BL6 murine cardiomyocytes becomes restricted >20-fold as molecular weight increases from 30 to 2,000, roughly as expected for pores with porin channel dimensions. Bodipy-FL ATP diffuses >40-fold slower than in free water at 25°C. From several fluorophores analyzed, bound fluorophore fractions range from 0.1 for a 2 kD FITC-labeled polyethylene glycol to 0.93 for sulforhodamine. Unbound fluorophores diffuse at 0.5-8 × 10-7 cm2/s (5-80 μm2/s). Analysis of Na/K pump and veratridine-modified Na channel currents suggests that Na diffusion is nearly unrestricted at 35°C (time constant for equilibration with the pipette tip, ∼20 s). Using multiple strategies, we estimate that at 35°C, ATP diffuses four to eight times slower than in free water. To address whether restrictions are caused more by protein or membrane networks, we verified first that a protein gel, 10 g% gelatin, restricts diffusion with strong dependence on molecular weight. Solute diffusion in membrane-extracted cardiac myofilaments, confined laterally by suction into large-diameter pipette tips, is less restricted than in intact myocytes. Notably, myofilaments extracted similarly from skeletal (diaphragm) myocytes are less restrictive. Solute diffusion in myocytes with sarcolemma permeabilized by β-escin (80 µM) is similar to diffusion in intact myocytes. Restrictions are strain-dependent, being twofold greater in BL6 myocytes than in CD1/J6/129svJ myocytes. Furthermore, longitudinal diffusion is 2.5-fold more restricted in CD1/J6/129svJ myocytes lacking the mitochondrial porin, VDAC1, than in WT CD1/J6/129svJ myocytes. Thus, mitochondria networks restrict long-range diffusion while presumably optimizing nucleotide transfer between myofilaments and mitochondria. We project that diffusion restrictions imposed by both myofilaments and the outer mitochondrial membrane are important determinants of total free cytoplasmic AMP and ADP (∼10 μM). However, the capacity of diffusion to deliver ATP to myofilaments remains ∼100-fold greater than ATP consumption.
Topics: Mice; Animals; Myocytes, Cardiac; Myofibrils; Mitochondria; Diffusion; Voltage-Dependent Anion Channels; Adenosine Triphosphate; Water
PubMed: 37555782
DOI: 10.1085/jgp.202213329 -
Journal of Neuroscience Methods Nov 2023Cerebrospinal fluid (CSF) collection and its analysis are common medical practices useful in the diagnosis, therapy, and prevention of central nervous system (CNS)...
BACKGROUND
Cerebrospinal fluid (CSF) collection and its analysis are common medical practices useful in the diagnosis, therapy, and prevention of central nervous system (CNS) disorders. In recent years, several types of research have improved our insight into CSF and its role in health and disease. Yet, many characteristics of this fluid remain to be fully understood.
NEW METHODS
Here, we describe how to collect CSF from embryonic, postnatal, and adult stages of the rat. In adults, CSF can be collected through simple stereotaxic surgery to expose the membrane overlying the cisterna magna (CM) of an anesthetized rat and collection of CSF through micropipette puncture through the membrane. In embryos and pups, CSF is aspirated, using a fire-polished micro-capillary pipette, from the CM of animals.
RESULTS
Application of these methods provides the maximum volume of pure, uncontaminated CSF (embryonic day 19: 10-15 microliter, postnatal day 5: 20-30 microliter, adults: 100-200 microliter) with a success rate of approximately 95% in every age.
COMPARISON WITH EXISTING METHODS
Compared to the existing protocols, these methods obtain considerable volumes of CSF, which may accelerate the measurement of biological markers in this fluid. Also, these techniques do not require surgical skills and according to the practical points mentioned during sampling, the procedures can be performed in rapid fashion.
CONCLUSION
We describe simple methods for collecting CSF in live rats. These protocols provide clean, uncontaminated CSF for experiments to understand the exact role of this fluid in the development and maintenance of the CNS health.
Topics: Rats; Animals; Spinal Puncture; Cisterna Magna; Specimen Handling; Biomarkers; Cerebrospinal Fluid
PubMed: 37722626
DOI: 10.1016/j.jneumeth.2023.109971 -
Lab on a Chip Jun 2024Microfluidic dispensing technologies often require additional equipment, posing challenges for their integration into point-of-care testing (POCT) applications. In...
Microfluidic dispensing technologies often require additional equipment, posing challenges for their integration into point-of-care testing (POCT) applications. In response to this challenge, we have developed a pipette-operable microfluidic device fabricated using 3D printing technology for precise liquid dispensing. This device features three reaction chambers and three distinct hydrophobic valves to control the flow direction of liquids. Through these valves, the pipette-operable microfluidic device can sequentially dispense and isolate the liquid into the three reaction chambers, allowing for the individual conduction of three distinct reactions. These hydrophobic valves, with optimized flow resistance and burst pressure, can sustain a volumetric flow rate of up to 25 μL s, making them compatible with a standard pipette, a syringe, or a dropper operation. Furthermore, the device is successfully used to operate with various liquids, including BSA, DMEM, FBS, plasma, and blood, representing that the device has the potential to be used for various applications. Additionally, distinct RT-LAMP primer sets have been incorporated for diagnosing SARS-CoV-2, influenza A, and influenza B within each chamber through lyophilization. This pipette-operable microfluidic device serves as a versatile tool for diagnosing these three diseases using a single loading process, with results readable by the naked eye or image assay within 30 minutes of incubation. Finally, the design concepts are extended to engineer a microfluidic device with 20 reaction chambers, offering significant potential for multi-disease diagnostics.
Topics: Lab-On-A-Chip Devices; Humans; Hydrophobic and Hydrophilic Interactions; SARS-CoV-2; Equipment Design; COVID-19; Point-of-Care Testing; Nucleic Acid Amplification Techniques; Microfluidic Analytical Techniques; Printing, Three-Dimensional
PubMed: 38758131
DOI: 10.1039/d4lc00209a -
Analytical and Bioanalytical Chemistry Jul 2023In this work, we present an in situ droplet-based derivatization method for fast tissue lipid profiling at multiple isomer levels. On-tissue derivatization for isomer...
In this work, we present an in situ droplet-based derivatization method for fast tissue lipid profiling at multiple isomer levels. On-tissue derivatization for isomer characterization was achieved in a droplet delivered by the TriVersa NanoMate LESA pipette. The derivatized lipids were then extracted and analyzed by the automated chip-based liquid extraction surface analysis (LESA) mass spectrometry (MS) followed by tandem MS to produce diagnostic fragment ions to reveal the lipid isomer structures. Three reactions, i.e., mCPBA epoxidation, photocycloaddition catalyzed by the photocatalyst Ir[dF(CF)ppy](dtbbpy)PF, and Mn(II) lipid adduction, were applied using the droplet-based derivatization to provide lipid characterization at carbon-carbon double-bond positional isomer and sn-positional isomer levels. Relative quantitation of both types of lipid isomers was also achieved based on diagnostic ion intensities. This method provides the flexibility of performing multiple derivatizations at different spots in the same functional region of an organ for orthogonal lipid isomer analysis using a single tissue slide. Lipid isomers were profiled in the cortex, cerebellum, thalamus, hippocampus, and midbrain of the mouse brain and 24 double-bond positional isomers and 16 sn-positional isomers showed various distributions in those regions. This droplet-based derivatization of tissue lipids allows fast profiling of multi-level isomer identification and quantitation and has great potential in tissue lipid studies requiring rapid sample-to-result turnovers.
Topics: Mice; Animals; Tandem Mass Spectrometry; Isomerism; Lipids
PubMed: 37017722
DOI: 10.1007/s00216-023-04653-3