agar and Dehydration

Modified agar pre-embedded paraffin embedding method was proposed to evaluate the effects on tissue integrity, histological morphology, protein and DNA detection in small specimens of core needle biopsies.. The core needle biopsy specimens of 10 patients with oral mucosal squamous cell carcinoma were subjected to modified agar pre-embedded paraffin embedding using molded embedding molds and conventional paraffin embedding respectively, the dehydration time of the former was 3.5 h and that of the latter was 12 h. After tissue treatment, H-E staining, histological morphology, immunohistochemistry (IHC), and DNA fluorescence in situ hybridization (FISH) were performed, respectively. The results were compared and analyzed using GraphPad Prism 9 software package.. The modified agar pre-embedding method was less difficult to perform than the agar pre-embedding method, and easier to be promoted. Compared with conventional paraffin embedding method, the tissue dehydration time was significantly reduced(P＜0.001), and the results of microscopic histological morphology and subsequent IHC and FISH assays were reliable.. The modified agar pre-embedded paraffin embedding method meets the requirements of clinical pathological diagnosis for tissue processing, and is worthy of clinical application for core needle biopsy specimens.

Topics: Agar; Biopsy; Biopsy, Large-Core Needle; Dehydration; DNA; Head and Neck Neoplasms; Humans; In Situ Hybridization, Fluorescence; Paraffin Embedding

The bacterial colony is a powerful experimental platform for broad biological research, and reaction-diffusion models are widely used to study the mechanisms of its formation process. However, there are still some crucial factors that drastically affect the colony growth but are not considered in the current models, such as the non-homogeneously distributed nutrient within the colony and the substantially decreasing expansion rate caused by agar dehydration. In our study, we propose two plausible reaction-diffusion models (the VN and MVN models) based on the above two factors and validate them against experimental data. Both models provide a plausible description of the non-homogeneously distributed nutrient within the colony and outperform the classical Fisher-Kolmogorov equation and its variation in better describing experimental data. Moreover, by accounting for agar dehydration, the MVN model captures how a colony's expansion slows down and the change of a colony's height profile over time. Furthermore, we demonstrate the existence of a traveling wave solution for the VN model.

Topics: Agar; Dehydration; Escherichia coli; Humans; Mathematical Concepts; Models, Biological

Plants are constantly exposed to various biological and non-biological stresses that endanger their lives. Drought stress is one of the abiotic stresses that have a great impact on the yield and life of plants and is one of the main causes of reduced crop yields. Reducing the effects of environmental stresses such as drought using methods such as irrigation, fertilizer application and appropriate planting methods is limited. Therefore, genetic modification of plants is an important effort to minimize the effect of environmental stresses. in this research, Twenty disinfected camelina seeds were cultured on the MS medium containing 3% sucrose, 0.8% agar and pH 5.8 under a laminar hood. After 14 days, the cotyledon explants (about 1 cm) were separated from the seedlings and placed on the callus induction medium. The MS callus induction medium containing 0.5 mg / l kinetin, 2 mg / l -2,4 D, 3% sucrose, 0.8% agar and pH 5.8. Samples were subcultured every two weeks to the same medium and calli were formed after 4 weeks. Then the calli were transferred to the medium containing a concentration of 30% PEG. To study gene expression, first callus samples were treated with liquid nitrogen and to study the effect of drought stress on gene expression, this sample was sent to Zagros Bioidea Company located in the Razi University Incubator. Gene expression was performed through microarray technology. The results showed that seven different genes whose expression increased by almost six times the control value can be mentioned, including Cold-acclimation protein (CAP160), NAC10, Abscisic acid (ABA), ABF4, CRK3, lysM domain receptor-like kinases (LYKs) and Basic/helix-loop-helix(bHLH130-like). Drought tolerance is not a genetically simple trait, but a quantitative and complex trait with various aspects that require the use of molecular methods to investigate the relevant mechanisms. This study aimed to investigate the expression of different genes of callus tissues of the Camelina plant under stress and non-stress conditions by microarray method.

Topics: Agar; Brassicaceae; Dehydration; Humans; Plants; Sucrose

The concept of water activity (a(w)) does not differentiate between water status resulting from the interaction of water with solutes, and that from interaction of water with matrices, which is termed matric potential (psi(m)). This study reports the effect of agar concentration (1.5, 3.0, 4.5, 6.0, and 7.5%, w/w) on matric potential of glycerol agar media (GA) and the germination and growth of xerophilic fungi (Eurotium herbariorum and E. rubrum) and non-xerophilic fungi (Aspergillus niger, A. flavus, and Penicillium roqueforti) on GA with or without sorbic acid (0.1-0.4%, w/w) at 0.90 a(w) and 0.95 a(w). The matric potential of GA decreased when the agar concentration increased from 1.5 to 7.5%. When the agar concentration increased at each a(w), the radial growth rate of the xerophilic fungi generally increased but the biomass density (biomass per unit area) decreased, whereas the radial growth rate of the non-xerophilic fungi generally decreased but the biomass density was unchanged. In the absence of sorbic acid, the time to germination of each species was similar for all agar concentrations. In the presence of sorbic acid, the time to germination of some species was significantly longer at higher agar concentrations (4.5%-7.5%) than 1.5% agar. This study demonstrated the inhibition effect on germination and growth of non-xerophilic fungi and xerophilic fungi by decreased matric potential resulting from increased agar concentrations, and the different responses of non-xerophilic fungi and xerophilic fungi to water stress from solutes and matrices. The concept of matric potential may be useful in food microbiology to provide a better understanding of fungal growth in complex food matrices.

Topics: Adaptation, Biological; Agar; Biomass; Culture Media; Dehydration; Fungi; Glycerol; Sorbic Acid; Water

Topics: Agar; Candida; Candida albicans; Dehydration; Oryza