scholarly journals Investigations of changes in the arabinogalactan proteins (AGPs) structure, size and composition during the fruit ripening process

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Agata Leszczuk ◽  
Adrian Zając ◽  
Magdalena Kurzyna-Szklarek ◽  
Justyna Cybulska ◽  
Artur Zdunek
Keyword(s):  
Molecular Mass ◽  
Immunogold Labelling ◽  
Structural Features ◽  
Arabinogalactan Proteins ◽  
Cellular Level ◽  
Ripening Process ◽  
Yariv Reagent ◽  
Specific Distribution ◽  
Membrane Components ◽  
Apple Fruits

AbstractArabinogalactan proteins (AGPs) are ubiquitous cell wall and plasma membrane components and are characterised by extensive glycosylation and heterogeneity of their carbohydrate and protein units. The aim of the study was to evaluate the structural features of AGPs present in apple fruits at different stages of the ripening process. AGPs were extracted using the Yariv reagent and examined using SDS-PAGE, immunoblotting, FT-IR, and AFM. In situ analysis, immunofluorescence (CLSM) and immunogold-labelling (TEM), were performed. We demonstrated that AGPs were indeed present in apple fruits at the different stages of the ripening process. The changes in the amount (1.52–2.08 mg g−1), diameter (152.73–75.05 nm), molecular mass (50–250 kDa), and distribution in the cell of AGPs demonstrate their variable presence and changeable structure during the ripening process. We propose specific wavenumbers, i.e. 1265 cm−1, 1117 cm−1, and 960 cm−1, which could be assigned to AGPs. The immunofluorescence and immunogold-labelling results indicate that the JIM13 antibody is the most characteristic for AGPs in apple fruits. This study quantitatively demonstrated for the first time that AGP accumulation occurs in ripe fruits, which is supported by the highest AGPs content, the highest molecular mass, and the appearance of a specific distribution pattern at the cellular level.

scholarly journals Synthesis and Characterization of a Fullerenol Derivative for Potential Biological Applications

2020 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Eduardo Ravelo-Nieto ◽  
Alvaro Duarte-Ruiz ◽  
Luis H. Reyes ◽  
Juan C. Cruz
Keyword(s):  
Phase Transfer ◽  
Protein A ◽  
Structural Features ◽  
Cellular Level ◽  
Cellulose Membrane ◽  
Cell Penetration ◽  
Covalent Functionalization ◽  
Dialysis Tubing ◽  
Surface Functionality

Several biological barriers are generally responsible for the limited delivery of cargoes at the cellular level. Fullerenols have unique structural features and possess suitable properties for interaction with the cells. This study aimed to synthesize and characterize a fullerenol derivative with desirable characteristics (size, charge, functionality) to develop cell penetration vehicles. Fullerenol was synthesized from fullerene (C60) solubilized in toluene, followed by hydroxylation with hydrogen peroxide and tetra-n-butylammonium hydroxide (TBAH) as a phase transfer catalyst. The obtained product was purified by a Florisil chromatography column (water as the eluent), followed by dialysis (cellulose membrane dialysis tubing) and freeze-drying (yield 66%). Subsequently, a silane coupling agent was conjugated on the fullerenol surface to render free amine functional groups for further covalent functionalization with other molecules. Characterization via UV–VIS, FTIR-ATR, Raman, DLS, and SEM techniques was conducted to evaluate the composition, size, morphology, surface functionality, and structural properties. We are currently working on the conjugation of the potent cell-penetrating agents Buforin II (BUFII) and the Outer Membrane Protein A (OmpA) on the surface of the fullerenol to estimate whether cell penetration and endosome escape are improved concerning conventional polymeric vehicles and our previous developments with iron oxide nanoparticles.

Tight junctions

1998 ◽  
Vol 111 (5) ◽  
pp. 541-547 ◽  
Author(s):  
M.S. Balda ◽  
K. Matter
Keyword(s):  
Endothelial Cells ◽  
Cell Growth ◽  
Tight Junctions ◽  
Diffusion Barrier ◽  
Basolateral Membrane ◽  
Intercellular Junctions ◽  
Cellular Level ◽  
Cellular Processes ◽  
Cell Growth And Differentiation ◽  
Membrane Components

Tight junctions are the most apical intercellular junctions of epithelial and endothelial cells and create a regulatable semipermeable diffusion barrier between individual cells. On a cellular level, they form an intramembrane diffusion fence that restricts the intermixing of apical and basolateral membrane components. In addition to these well defined functions, more recent evidence suggests that tight junctions are also involved in basic cellular processes like the regulation of cell growth and differentiation.

scholarly journals Arabinogalactan Proteins in Plant Roots – An Update on Possible Functions

2021 ◽  
Vol 12 ◽  
Author(s):  
Dagmar Hromadová ◽  
Aleš Soukup ◽  
Edita Tylová
Keyword(s):  
Cell Wall ◽  
Regulatory Networks ◽  
Developmental Plasticity ◽  
Molecular Mechanisms ◽  
Arabinogalactan Proteins ◽  
Cellular Level ◽  
Environmental Response ◽  
Essential Components ◽  
Surface Signaling ◽  
Cell Surface Signaling

Responsiveness to environmental conditions and developmental plasticity of root systems are crucial determinants of plant fitness. These processes are interconnected at a cellular level with cell wall properties and cell surface signaling, which involve arabinogalactan proteins (AGPs) as essential components. AGPs are cell-wall localized glycoproteins, often GPI-anchored, which participate in root functions at many levels. They are involved in cell expansion and differentiation, regulation of root growth, interactions with other organisms, and environmental response. Due to the complexity of cell wall functional and regulatory networks, and despite the large amount of experimental data, the exact molecular mechanisms of AGP-action are still largely unknown. This dynamically evolving field of root biology is summarized in the present review.

The First Intrinsic Tenase Complex Inhibitor with Serine Protease Structure Offers a New Perspective in Anticoagulant Therapy

2018 ◽  
Vol 118 (10) ◽  
pp. 1713-1728 ◽  
Author(s):  
Zorica Latinović ◽  
Adrijana Leonardi ◽  
Lidija Kovačič ◽  
Cho Koh ◽  
Jernej Šribar ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Serine Protease ◽  
Blood Coagulation ◽  
Three Dimensional ◽  
Serine Proteinase ◽  
Medical Application ◽  
Structural Features ◽  
Coagulation System ◽  
Three Dimensional Model ◽  
Excessive Bleeding

AbstractComponents of the intrinsic blood coagulation pathway, among them factor VIIIa (FVIIIa), have been recognized as suitable therapeutic targets to treat venous thromboembolism, pathological process behind two very serious cardiovascular diseases, deep vein thrombosis and pulmonary embolism. Here, we describe a unique glycoprotein from the nose-horned viper (Vipera ammodytes ammodytes [Vaa]) venom, Vaa serine proteinase homolog 1 (VaaSPH-1), structurally a serine protease but without an enzymatic activity and expressing potent anticoagulant action in human blood. We demonstrated that one of its targets in the blood coagulation system is FVIIIa of the intrinsic tenase complex, where it antagonizes the binding of FIXa. Anticoagulants with such characteristics are intensively sought, as they would be much safer for medical application as the contemporary drugs, which frequently induce excessive bleeding and other complications. VaaSPH-1 is unlikely to be orally available for chronic usage as it has molecular mass of 35 kDa. However, it represents a very promising template to design low molecular mass FVIIIa-directed anticoagulant substances, based on structural features of the interaction surface between VaaSPH-1 and FVIIIa. To this end, we constructed a three-dimensional model of VaaSPH-1 bound to FVIIIa. The model exposes the 157–loop and the preceding α-helix as the most appropriate structural elements of VaaSPH-1 to be considered as a guideline to synthesize small FVIIIa-binding molecules, potential new generation of anticoagulants.

scholarly journals Isolation of infectious, non-fibrillar and oligomeric prions from a genetic prion disease

Brain ◽  
2020 ◽  
Vol 143 (5) ◽  
pp. 1512-1524 ◽  
Author(s):  
Ilaria Vanni ◽  
Laura Pirisinu ◽  
Claudia Acevedo-Morantes ◽  
Razieh Kamali-Jamil ◽  
Vineet Rathod ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Amyloid Fibrils ◽  
Morphological Characteristics ◽  
Immunogold Labelling ◽  
Structural Features ◽  
Cellular Prion Protein ◽  
Proteinase K ◽  
Supernatant Fraction ◽  
C Terminus ◽  
Electron Microscopy Analysis

Abstract Prions are transmissible agents causing lethal neurodegenerative diseases that are composed of aggregates of misfolded cellular prion protein (PrPSc). Despite non-fibrillar oligomers having been proposed as the most infectious prion particles, prions purified from diseased brains usually consist of large and fibrillar PrPSc aggregates, whose protease-resistant core (PrPres) encompasses the whole C-terminus of PrP. In contrast, PrPSc from Gerstmann-Sträussler-Scheinker disease associated with alanine to valine substitution at position 117 (GSS-A117V) is characterized by a small protease-resistant core, which is devoid of the C-terminus. We thus aimed to investigate the role of this unusual PrPSc in terms of infectivity, strain characteristics, and structural features. We found, by titration in bank voles, that the infectivity of GSS-A117V is extremely high (109.3 ID50 U/g) and is resistant to treatment with proteinase K (109.0 ID50 U/g). We then purified the proteinase K-resistant GSS-A117V prions and determined the amount of infectivity and PrPres in the different fractions, alongside the morphological characteristics of purified PrPres aggregates by electron microscopy. Purified pellet fractions from GSS-A117V contained the expected N- and C-terminally cleaved 7 kDa PrPres, although the yield of PrPres was low. We found that this low yield depended on the low density/small size of GSS-A117V PrPres, as it was mainly retained in the last supernatant fraction. All fractions were highly infectious, thus confirming the infectious nature of the 7 kDa PrPres, with infectivity levels that directly correlated with the PrPres amount detected. Finally, electron microscopy analysis of these fractions showed no presence of amyloid fibrils, but only very small and indistinct, non-fibrillar PrPresparticles were detected and confirmed to contain PrP via immunogold labelling. Our study demonstrates that purified aggregates of 7 kDa PrPres, spanning residues ∼90–150, are highly infectious oligomers that encode the biochemical and biological strain features of the original sample. Overall, the autocatalytic behaviour of the prion oligomers reveals their role in the propagation of neurodegeneration in patients with Gerstmann-Sträussler-Scheinker disease and implies that the C-terminus of PrPSc is dispensable for infectivity and strain features for this prion strain, uncovering the central PrP domain as the minimal molecular component able to encode infectious prions. These findings are consistent with the hypothesis that non-fibrillar prion particles are highly efficient propagators of disease and provide new molecular and morphological constraints on the structure of infectious prions.

scholarly journals Structural features of the low-molecular-mass human salivary mucin

1992 ◽  
Vol 287 (2) ◽  
pp. 639-643 ◽  
Author(s):  
M S Reddy ◽  
L A Bobek ◽  
G G Haraszthy ◽  
A R Biesbrock ◽  
M J Levine
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Molecular Mass ◽  
Gel Filtration ◽  
Structural Features ◽  
Cdna Expression Library ◽  
Cdna Clones ◽  
Expression Library ◽  
Mrna Species ◽  
Salivary Mucin

The low-molecular-mass human salivary mucin has at least two isoforms, MG2a and MG2b, that differ primarily in their sialic acid and fucose content. In this study, we characterize further these isoforms, particularly their peptide moieties. Trypsin digests of MG2a and MG2b yielded high- and low-molecular-mass glycopeptides following gel filtration on Sephacryl S-300. The larger glycopeptides from MG2a and MG2b had similar amino acid compositions and identical N-terminal sequences, suggesting common structural features between their peptides. An oligonucleotide probe generated from the amino acid sequence of the smaller glycopeptide from MG2a was employed in Northern-blot analysis. This probe specifically hybridized to two mRNA species from human submandibular and sublingual glands. A cDNA clone selected from a human submandibular gland cDNA expression library with antibody generated against deglycosylated MG2a also hybridized to these two mRNA species. In both cases, the larger mRNA was polydisperse, and the hybridization signal was more intense in the sublingual gland. In addition, the N-terminal amino acid sequence of the larger glycopeptide was found to be part of one of the selected MG2 cDNA clones.

scholarly journals Biochemical analysis of a bladder-cancer-associated mucin: structural features and epitope characterization

1997 ◽  
Vol 321 (3) ◽  
pp. 889-896 ◽  
Author(s):  
Alain BERGERON ◽  
Hélène LaRUE ◽  
Yves FRADET
Keyword(s):  
Molecular Mass ◽  
Structural Features ◽  
High Molecular Mass ◽  
Antigenic Determinants ◽  
Heat Denaturation ◽  
Appreciable Effect ◽  
Carbohydrate Epitopes ◽  
Reducing Conditions ◽  
Epitope Characterization ◽  
Mass Component

Three monoclonal antibodies (mAbs), M344, M300 and M75, were shown to define a unique tumour-associated antigen (TAA) of superficial bladder tumours. The antigenic determinants are expressed on a very-high-molecular-mass component and, in about 50% of the positive samples, one determinant is also detected on a 62 kDa molecular species, observed only under reducing conditions. The objectives of the present study were to characterize further this TAA by analysing (1) the biochemical nature of the epitopes recognized by the three mAbs, and (2) the biochemical and structural features of the molecule bearing them. The antigenicity was resistant to heat denaturation, trypsin and α-chymotrypsin treatments but highly sensitive to papain and Pronase digestion. NaIO4 oxidation decreased reactivity to mAbs M344 and M300 but enhanced reactivity to mAb M75. The three determinants were insensitive to β-galactosidase and α-l-fucosidase but were sensitive to Vibrio choleraeneuraminidase. None of the three mAbs reacted with ovine, bovine or porcine submaxillary mucins. Deglycosylation with O-glycosidase or trifluoromethanesulphonic acid completely abolished the reactivity of the mAbs whereas N-glycosidase F deglycosylation had no appreciable effect. The presence on the molecule of cryptic Galβ(1→3)GalNAc as a major core disaccharide was demonstrated by a heterologous sandwich assay using mAb M75 and peanut agglutinin. Thiol reduction using β-mercaptoethanol increased mobility of the high-molecular-mass component in polyacrylamide gels. We thus conclude that mAbs M344 and M300 react with sialylated carbohydrate epitopes, and mAb M75 reacts with a partially cryptic and periodate-resistant sialylated epitope expressed on a typical secreted high-molecular-mass oligomeric mucin which we named MAUB for mucin antigen of the urinary bladder.

scholarly journals Changes in Polyphenol Content and Polyphonoloxidase Activity of Apple Fruits during Ripening Process.

1998 ◽  
Vol 45 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Yasuko SANNOMARU ◽  
Osamu KATAYAMA ◽  
Yoshiki KASHIMURA ◽  
Katsuyoshi KANEKO
Keyword(s):  
Polyphenol Content ◽  
Ripening Process ◽  
Apple Fruits
Sign in / Sign up

Export Citation Format

Share Document