Total Soluble Protein Extraction for Improved Proteomic Analysis of Transgenic Rice Plant Roots

Optimizing Phycocyanin Extraction from Cyanobacterial Biomass: A Comparative Study of Freeze-Thaw Cycling with Various Solvents

Cyanobacterial phycocyanin pigment is widely utilized for its properties in various industries, including food, cosmetics, and pharmaceuticals. Despite its potential, challenges exist, such as extraction methods impacting yield, stability, and purity. This study investigates the impact of the number of freeze-thaw (FT) cycles on the extraction of phycocyanin from the wet biomass of four cyanobacteria species (Arthrospira platensis, Chlorogloeopsis fritschii, Phormidium sp., and Synechocystis sp.), along with the impact of five extraction solutions (Tris-HCl buffer, phosphate buffer, CaCl2, deionized water, and tap water) at various pH values. Synechocystis sp. exhibited the highest phycocyanin content among the studied species. For A. platensis, Tris-HCl buffer yielded maximum phycocyanin concentration from the first FT cycle, while phosphate buffer provided satisfactory results from the second cycle. Similarly, Tris-HCl buffer showed promising results for C. fritschii (68.5% of the maximum from the first cycle), with the highest concentration (~12% w/w) achieved during the seventh cycle, using phosphate buffer. Phormidium sp. yielded the maximum pigment concentration from the first cycle using tap water. Among species-specific optimal extraction solutions, Tris-HCl buffer demonstrated sufficient extraction efficacy for all species, from the first cycle. This study represents an initial step toward establishing a universal extraction method for phycocyanin from diverse cyanobacteria species.

Comparative proteomic analysis of chromosome segment substitution lines of Thai jasmine rice KDML105 under short-term salinity stress

Heat shock proteins, ROS detoxifying enzymes, and ion homeostasis proteins, together with proteins in carbohydrate metabolism, cell structure, brassinosteroids, and carotenoid biosynthesis pathway were up-regulated in CSSLs under salinity stress. Rice is one of the most consumed staple foods worldwide. Salinity stress is a serious global problem affecting rice productivity. Many attempts have been made to select or produce salinity-tolerant rice varieties. Genetics and biochemical approaches were used to study the salinity-responsive pathway in rice to develop salinity tolerant strains. This study investigated the proteomic profiles of chromosome segment substitution lines (CSSLs) developed from KDML105 (Khao Dawk Mali 105, a Thai jasmine rice cultivar) under salinity stress. The CSSLs showed a clear resistant phenotype in response to 150 mM NaCl treatment compared to the salinity-sensitive line, IR29. Liquid chromatography-tandem mass spectrometry using the Ultimate 3000 Nano/Capillary LC System coupled to a Hybrid Quadrupole Q-Tof Impact II™ equipped with a nano-captive spray ion source was applied for proteomic analysis. Based on our criteria, 178 proteins were identified as differentially expressed proteins under salinity stress. Protein functions in DNA replication and transcription, and stress and defense accounted for the highest proportions in response to salinity stress, followed by protein transport and trafficking, carbohydrate metabolic process, signal transduction, and cell structure. The protein interaction network among the 75 up-regulated proteins showed connections between proteins involved in cell wall synthesis, transcription, translation, and in defense responses.

Extraction and identification of biologically important proteins from the medicinal plant God's crown (Phaleria macrocarpa)

The fruit and leaf of God's crown (Phaleria macrocarpa) have been traditionally used to treat a wide variety of diseases. However, the proteins of this tropical plant are still heavily understudied. Three protein extraction methods; phenol (Phe), trichloroacetic acid (TCA)-acetone-phenol (TCA-A-Phe), and ultrasonic (Ult) were compared on the fruit and leaf of P. macrocarpa. The Phe extraction method showed the highest percentage of recovered protein after the resolubilization process for both leaf (12.24%) and fruit (30.41%) based on protein yields of the leaf (6.15 mg/g) and fruit (36.98 mg/g). Phe and TCA-A-Phe extraction methods gave well-resolved bands over a wide range of molecular weights through sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Following liquid chromatography-tandem mass spectrometry analysis, proteins identified through the Phe extraction method were 30%-35% enzymatic proteins, including oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases that possess various biological functions. PRACTICAL APPLICATIONS: Every part of God's crown plant is traditionally consumed to treat various illnesses. While plant's benefits are well known and have led to a plethora of health products, the proteome remains mostly unknown. This study compares three protein extraction methods for the leaf and fruit of P. macrocarpa and identifies their proteins thru LC-MS/MS coupled with PEAKS. These method comparisons can be a guide for works on other plants as well. In addition, the proteomics data from this study may shed light on the functional properties of these plant parts and their products.

Root-type ferredoxin-NADP+ oxidoreductase isoforms in Arabidopsis thaliana: Expression patterns, location and stress responses

In Arabidopsis, two leaf-type ferredoxin-NADP⁺ oxidoreductase (LFNR) isoforms function in photosynthetic electron flow in reduction of NADP⁺ , while two root-type FNR (RFNR) isoforms catalyse reduction of ferredoxin in non-photosynthetic plastids. As the key to understanding, the function of RFNRs might lie in their spatial and temporal distribution in different plant tissues and cell types, we examined expression of RFNR1 and RFNR2 genes using β-glucuronidase (GUS) reporter lines and investigated accumulation of distinct RFNR isoforms using a GFP approach and Western blotting upon various stresses. We show that while RFNR1 promoter is active in leaf veins, root tips and in the stele of roots, RFNR2 promoter activity is present in leaf tips and root stele, epidermis and cortex. RFNR1 protein accumulates as a soluble protein within the plastids of root stele cells, while RFNR2 is mainly present in the outer root layers. Ozone treatment of plants enhanced accumulation of RFNR1, whereas low temperature treatment specifically affected RFNR2 accumulation in roots. We further discuss the physiological roles of RFNR1 and RFNR2 based on characterization of rfnr1 and rfnr2 knock-out plants and show that although the function of these proteins is partly redundant, the RFNR proteins are essential for plant development and survival.

Electron transport pathways in isolated chromoplasts from Narcissus pseudonarcissus L

During daffodil flower development, chloroplasts differentiate into photosynthetically inactive chromoplasts having lost functional photosynthetic reaction centers. Chromoplasts exhibit a respiratory activity reducing oxygen to water and generating ATP. Immunoblots revealed the presence of the plastid terminal oxidase (PTOX), the NAD(P)H dehydrogenase (NDH) complex, the cytochrome b₆ f complex, ATP synthase and several isoforms of ferredoxin-NADP⁺ oxidoreductase (FNR), and ferredoxin (Fd). Fluorescence spectroscopy allowed the detection of chlorophyll a in the cytochrome b₆ f complex. Here we characterize the electron transport pathway of chromorespiration by using specific inhibitors for the NDH complex, the cytochrome b₆ f complex, FNR and redox-inactive Fd in which the iron was replaced by gallium. Our data suggest an electron flow via two separate pathways, both reducing plastoquinone (PQ) and using PTOX as oxidase. The first oxidizes NADPH via FNR, Fd and cytochrome b_h of the cytochrome b₆ f complex, and does not result in the pumping of protons across the membrane. In the second, electron transport takes place via the NDH complex using both NADH and NADPH as electron donor. FNR and Fd are not involved in this pathway. The NDH complex is responsible for the generation of the proton gradient. We propose a model for chromorespiration that may also be relevant for the understanding of chlororespiration and for the characterization of the electron input from Fd to the cytochrome b₆ f complex during cyclic electron transport in chloroplasts.