Structural features of vegetative organs in some Ficus carica L. cultivars cultured in vitro

2021 ◽  
pp. 47-52
Author(s):  
O.V. Mitrofanova ◽  
V.A. Brailko ◽  
E.L. Shishkina ◽  
I.V. Mitrofanova
Author(s):  
Godfrey C. Hoskins ◽  
Betty B. Hoskins

Metaphase chromosomes from human and mouse cells in vitro are isolated by micrurgy, fixed, and placed on grids for electron microscopy. Interpretations of electron micrographs by current methods indicate the following structural features.Chromosomal spindle fibrils about 200Å thick form fascicles about 600Å thick, wrapped by dense spiraling fibrils (DSF) less than 100Å thick as they near the kinomere. Such a fascicle joins the future daughter kinomere of each metaphase chromatid with those of adjacent non-homologous chromatids to either side. Thus, four fascicles (SF, 1-4) attach to each metaphase kinomere (K). It is thought that fascicles extend from the kinomere poleward, fray out to let chromosomal fibrils act as traction fibrils against polar fibrils, then regroup to join the adjacent kinomere.


2018 ◽  
Vol 24 (17) ◽  
pp. 1899-1904
Author(s):  
Daniel Fabio Kawano ◽  
Marcelo Rodrigues de Carvalho ◽  
Mauricio Ferreira Marcondes Machado ◽  
Adriana Karaoglanovic Carmona ◽  
Gilberto Ubida Leite Braga ◽  
...  

Background: Fungal secondary metabolites are important sources for the discovery of new pharmaceuticals, as exemplified by penicillin, lovastatin and cyclosporine. Searching for secondary metabolites of the fungi Metarhizium spp., we previously identified tyrosine betaine as a major constituent. Methods: Because of the structural similarity with other inhibitors of neprilysin (NEP), an enzyme explored for the treatment of heart failure, we devised the synthesis of tyrosine betaine and three analogues to be subjected to in vitro NEP inhibition assays and to molecular modeling studies. Results: In spite of the similar binding modes with other NEP inhibitors, these compounds only displayed moderate inhibitory activities (IC50 ranging from 170.0 to 52.9 µM). However, they enclose structural features required to hinder passive blood brain barrier permeation (BBB). Conclusions: Tyrosine betaine remains as a starting point for the development of NEP inhibitors because of the low probability of BBB permeation and, consequently, of NEP inhibition at the Central Nervous System, which is associated to an increment in the Aβ levels and, accordingly, with a higher risk for the onset of Alzheimer's disease.


2020 ◽  
Vol 21 (10) ◽  
pp. 955-964 ◽  
Author(s):  
Mengjie Liu ◽  
John Wade ◽  
Mohammed Akhter Hossain

: Ghrelin is a 28-amino acid octanoylated peptide hormone that is implicated in many physiological and pathophysiological processes. Specific visualization of ghrelin and its cognate receptor using traceable ligands is crucial in elucidating the localization, functions, and expression pattern of the peptide’s signaling pathway. Here 12 representative radio- and fluorescently-labeled peptide-based ligands are reviewed for in vitro and in vivo imaging studies. In particular, the focus is on their structural features, pharmacological properties, and applications in further biochemical research.


2018 ◽  
Vol 18 (5) ◽  
pp. 321-368 ◽  
Author(s):  
Juan A. Bisceglia ◽  
Maria C. Mollo ◽  
Nadia Gruber ◽  
Liliana R. Orelli

Neglected diseases due to the parasitic protozoa Leishmania and Trypanosoma (kinetoplastids) affect millions of people worldwide, and the lack of suitable treatments has promoted an ongoing drug discovery effort to identify novel nontoxic and cost-effective chemotherapies. Polyamines are ubiquitous small organic molecules that play key roles in kinetoplastid parasites metabolism, redox homeostasis and in the normal progression of cell cycles, which differ from those found in the mammalian host. These features make polyamines attractive in terms of antiparasitic drug development. The present work provides a comprehensive insight on the use of polyamine derivatives and related nitrogen compounds in the chemotherapy of kinetoplastid diseases. The amount of literature on this subject is considerable, and a classification considering drug targets and chemical structures were made. Polyamines, aminoalcohols and basic heterocycles designed to target the relevant parasitic enzyme trypanothione reductase are discussed in the first section, followed by compounds directed to less common targets, like parasite SOD and the aminopurine P2 transporter. Finally, the third section comprises nitrogen compounds structurally derived from antimalaric agents. References on the chemical synthesis of the selected compounds are reported together with their in vivo and/or in vitro IC50 values, and structureactivity relationships within each group are analyzed. Some favourable structural features were identified from the SAR analyses comprising protonable sites, hydrophobic groups and optimum distances between them. The importance of certain pharmacophoric groups or amino acid residues in the bioactivity of polyamine derived compounds is also discussed.


2021 ◽  
Vol 40 (2) ◽  
pp. 205-222
Author(s):  
Monica Scali ◽  
Alessandra Moscatelli ◽  
Luca Bini ◽  
Elisabetta Onelli ◽  
Rita Vignani ◽  
...  

AbstractPollen tube elongation is characterized by a highly-polarized tip growth process dependent on an efficient vesicular transport system and largely mobilized by actin cytoskeleton. Pollen tubes are an ideal model system to study exocytosis, endocytosis, membrane recycling, and signaling network coordinating cellular processes, structural organization and vesicular trafficking activities required for tip growth. Proteomic analysis was applied to identifyNicotiana tabacumDifferentially Abundant Proteins (DAPs) after in vitro pollen tube treatment with membrane trafficking inhibitors Brefeldin A, Ikarugamycin and Wortmannin. Among roughly 360 proteins separated in two-dimensional gel electrophoresis, a total of 40 spots visibly changing between treated and control samples were identified by MALDI-TOF MS and LC–ESI–MS/MS analysis. The identified proteins were classified according to biological processes, and most proteins were related to pollen tube energy metabolism, including ammino acid synthesis and lipid metabolism, structural features of pollen tube growth as well modification and actin cytoskeleton organization, stress response, and protein degradation. In-depth analysis of proteins corresponding to energy-related pathways revealed the male gametophyte to be a reliable model of energy reservoir and dynamics.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1602
Author(s):  
Anna Elizarova ◽  
Alexey Sokolov ◽  
Valeria Kostevich ◽  
Ekaterina Kisseleva ◽  
Evgeny Zelenskiy ◽  
...  

As shown recently, oleic acid (OA) in complex with lactoferrin (LF) causes the death of cancer cells, but no mechanism(s) of that toxicity have been disclosed. In this study, constitutive parameters of the antitumor effect of LF/OA complex were explored. Complex LF/OA was prepared by titrating recombinant human LF with OA. Spectral analysis was used to assess possible structural changes of LF within its complex with OA. Structural features of apo-LF did not change within the complex LF:OA = 1:8, which was toxic for hepatoma 22a cells. Cytotoxicity of the complex LF:OA = 1:8 was tested in cultured hepatoma 22a cells and in fresh erythrocytes. Its anticancer activity was tested in mice carrying hepatoma 22a. In mice injected daily with LF-8OA, the same tumor grew significantly slower. In 20% of animals, the tumors completely resolved. LF alone was less efficient, i.e., the tumor growth index was 0.14 for LF-8OA and 0.63 for LF as compared with 1.0 in the control animals. The results of testing from 48 days after the tumor inoculation showed that the survival rate among LF-8OA-treated animals was 70%, contrary to 0% rate in the control group and among the LF-treated mice. Our data allow us to regard the complex of LF and OA as a promising tool for cancer treatment.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qiuye Li ◽  
W. Michael Babinchak ◽  
Witold K. Surewicz

AbstractAmyotrophic lateral sclerosis and several other neurodegenerative diseases are associated with brain deposits of amyloid-like aggregates formed by the C-terminal fragments of TDP-43 that contain the low complexity domain of the protein. Here, we report the cryo-EM structure of amyloid formed from the entire TDP-43 low complexity domain in vitro at pH 4. This structure reveals single protofilament fibrils containing a large (139-residue), tightly packed core. While the C-terminal part of this core region is largely planar and characterized by a small proportion of hydrophobic amino acids, the N-terminal region contains numerous hydrophobic residues and has a non-planar backbone conformation, resulting in rugged surfaces of fibril ends. The structural features found in these fibrils differ from those previously found for fibrils generated from short protein fragments. The present atomic model for TDP-43 LCD fibrils provides insight into potential structural perturbations caused by phosphorylation and disease-related mutations.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qin Gong ◽  
Kim Robinson ◽  
Chenrui Xu ◽  
Phuong Thao Huynh ◽  
Kelvin Han Chung Chong ◽  
...  

AbstractNod-like receptor (NLR) proteins activate pyroptotic cell death and IL-1 driven inflammation by assembling and activating the inflammasome complex. Closely related sensor proteins NLRP1 and CARD8 undergo unique auto-proteolysis-dependent activation and are implicated in auto-inflammatory diseases; however, their mechanisms of activation are not understood. Here we report the structural basis of how the activating domains (FIINDUPA-CARD) of NLRP1 and CARD8 self-oligomerize to assemble distinct inflammasome complexes. Recombinant FIINDUPA-CARD of NLRP1 forms a two-layered filament, with an inner core of oligomerized CARD surrounded by an outer ring of FIINDUPA. Biochemically, self-assembled NLRP1-CARD filaments are sufficient to drive ASC speck formation in cultured human cells—a process that is greatly enhanced by NLRP1-FIINDUPA which forms oligomers in vitro. The cryo-EM structures of NLRP1-CARD and CARD8-CARD filaments, solved here at 3.7 Å, uncover unique structural features that enable NLRP1 and CARD8 to discriminate between ASC and pro-caspase-1. In summary, our findings provide structural insight into the mechanisms of activation for human NLRP1 and CARD8 and reveal how highly specific signaling can be achieved by heterotypic CARD interactions within the inflammasome complexes.


2014 ◽  
Vol 42 (6) ◽  
pp. 1773-1779 ◽  
Author(s):  
Lubna Freihat ◽  
Victor Muleya ◽  
David T. Manallack ◽  
Janet I. Wheeler ◽  
Helen R. Irving

Over 30 receptor-like kinases contain a guanylate cyclase (GC) catalytic centre embedded within the C-terminal region of their kinase domain in the model plant Arabidopsis. A number of the kinase GCs contain both functional kinase and GC activity in vitro and the natural ligands of these receptors stimulate increases in cGMP within isolated protoplasts. The GC activity could be described as a minor or moonlighting activity. We have also identified mammalian proteins that contain the novel GC centre embedded within kinase domains. One example is the interleukin 1 receptor-associated kinase 3 (IRAK3). We compare the GC functionality of the mammalian protein IRAK3 with the cytoplasmic domain of the plant prototype molecule, the phytosulfokine receptor 1 (PSKR1). We have developed homology models of these molecules and have undertaken in vitro experiments to compare their functionality and structural features. Recombinant IRAK3 produces cGMP at levels comparable to those produced by PSKR1, suggesting that IRAK3 contains GC activity. Our findings raise the possibility that kinase-GCs may switch between downstream kinase-mediated or cGMP-mediated signalling cascades to elicit desired outputs to particular stimuli. The challenge now lies in understanding the interaction between the GC and kinase domains and how these molecules utilize their dual functionality within cells.


2021 ◽  
pp. 185-190
Author(s):  
I.V. Mitrofanova ◽  
V.A. Brailko ◽  
N.P. Lesnikova-Sedoshenko ◽  
N.N. Ivanova ◽  
O.V. Mitrofanova

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