scholarly journals Evaluation of the Physicochemical Properties of Chitosans in Inducing the Defense Response of Coffea arabica against the Fungus Hemileia vastatrix

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1940
Author(s):  
Julio César López-Velázquez ◽  
José Nabor Haro-González ◽  
Soledad García-Morales ◽  
Hugo Espinosa-Andrews ◽  
Diego Eloyr Navarro-López ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Protective Effect ◽  
Defense Response ◽  
Biological Properties ◽  
Hemileia Vastatrix ◽  
Food Grade ◽  
Coffee Rust ◽  
Wide Range ◽  
Activity Of Enzymes ◽  
Coffee Plants

Chitosan is a natural polymer, and its biological properties depend on factors such as the degree of deacetylation and polymerization, viscosity, molecular mass, and dissociation constant. Chitosan has multiple advantages: it is biodegradable, biocompatible, safe, inexpensive, and non-toxic. Due to these characteristics, it has a wide range of applications. In agriculture, one of the most promising properties of chitosan is as an elicitor in plant defense against pathogenic microorganisms. In this work, four kinds of chitosan (practical grade, low molecular weight, medium molecular weight, and high-density commercial food grade) were used in concentrations of 0.01 and 0.05% to evaluate its protective effect against coffee rust. The best treatment was chosen to evaluate the defense response in coffee plants. The results showed a protective effect using practical-grade and commercial food-grade chitosan. In addition, the activity of enzymes with β-1,3 glucanase and peroxidase was induced, and an increase in the amount of phenolic compounds was observed in plants treated with high-molecular-weight chitosan at 0.05%; therefore, chitosan can be considered an effective molecule for controlling coffee rust.

scholarly journals Kefiran biopolymer: Evaluation of its physicochemical and biological properties

2018 ◽  
Vol 33 (5) ◽  
pp. 461-478 ◽  
Author(s):  
Hajer Radhouani ◽  
Cristiana Gonçalves ◽  
Fátima R Maia ◽  
Joaquim M Oliveira ◽  
Rui L Reis
Keyword(s):  
Molecular Weight ◽  
Photoelectron Spectroscopy ◽  
Average Molecular Weight ◽  
Structural Features ◽  
Biological Properties ◽  
Health Claims ◽  
Extrusion Force ◽  
Wide Range ◽  
Physicochemical And Biological Properties ◽  
Kefir Grains

Kefiran, an exopolysaccharide produced by lactic acid bacteria, has received a great interest due to a variety of health claims. In this study, we aim to investigate the physicochemical and biological properties of Kefiran polysaccharide extracted from Portuguese kefir grains. The kefir growth rate was about 56% (w/w) at room temperature and the kefir pH after 24 h was about 4.6. The obtained yield of Kefiran polysaccharide extracted from the kefir grains was about 4.26% (w/w). The Kefiran structural features were showed in the 1H nuclear magnetic resonance spectrum. The bands observed in the infrared spectrum confirmed that the Kefiran had a β-configuration; and the X-ray photoelectron spectroscopy analysis confirmed the structure and composition of Kefiran and revealed a C/O atomic ratio of 1.46. Moreover, Kefiran showed an average molecular weight (Mw) of 534 kDa and a number-average molecular weight (Mn) of 357 kDa. Regarding the rheological data obtained, Kefiran showed an interesting adhesive performance accompanied by a pseudoplastic behavior, and the extrusion force of Kefiran was 1 N. Furthermore, Kefiran exhibited a higher resistance to hyaluronidase degradation than hyaluronic acid. Finally, Kefiran showed a lack of cytotoxic response through its ability to support metabolic activity and proliferation of L929 cells, and had no effect on these cells’ morphology. Our research suggested that Kefiran polymer has attractive and interesting properties for a wide range of biomedical applications, such as tissue engineering and regenerative medicine.

Overview of Enzyme Engineering Towards the Production of Hyaluronic Acid with Tailored Molecular Weight

2021 ◽  
Vol 23 ◽  
Author(s):  
Tahereh Ebrahimi ◽  
Kamran Hosseini ◽  
Hossein Ahangari ◽  
Pourya Gholizadeh ◽  
Vahideh Tarhriz
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Critical Role ◽  
Biological Properties ◽  
Research Field ◽  
Enzyme Engineering ◽  
The Body ◽  
Synthesis Process ◽  
Hyaluronan Synthase ◽  
Wide Range

: Hyaluronic acid or hyaluronan (HA) is a natural biopolymer composed of D-glucuronic acid and N-acetylglucosamine units, distributed as a non-sulfated and anionic glycosaminoglycan in important tissues of the body, and is commercially and biologically important. Its biological properties are determined by the molecular weight and dispersity which are suitable for particular medical and cosmetic applications. The synthesis of well-defined and monodisperse HA is still a significant obstacle and an impressive research field for advanced medical applications. High polydispersity by bacterial fermentation, the lack of knowledge of the mechanism required to start and continue the synthesis process, increased cost of raw materials to produce HA, clarification and explanation of factors limiting synthesis in bacterial systems are among the important challenges of hyaluronic acid synthesis. Hyaluronan synthase plays a critical role in HA molecular mass by producing a wide range of HA involved in various biological processes. Hyaluronan biosynthesis has been considered extensively; however, the control of its size and weight during the synthesis process is poorly investigated. This review focuses on these uncharted biochemical details to obtain the uniform chain lengths of Hyaluronan by protein engineering and regulating the function of Hyaluronan synthase.

scholarly journals Isobornylchalcones as Scaffold for the Synthesis of Diarylpyrazolines with Antioxidant Activity

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3579
Author(s):  
Svetlana A. Popova ◽  
Evgenia V. Pavlova ◽  
Oksana G. Shevchenko ◽  
Irina Yu. Chukicheva ◽  
Aleksandr V. Kutchin
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Properties ◽  
Biological Properties ◽  
High Reactivity ◽  
Biologically Active ◽  
Brain Lipids ◽  
Wide Range ◽  
Privileged Structure ◽  
Vitro Model

The pyrazoline ring is defined as a “privileged structure” in medicinal chemistry. A variety of pharmacological properties of pyrazolines is associated with the nature and position of various substituents, which is especially evident in diarylpyrazolines. Compounds with a chalcone fragment show a wide range of biological properties as well as high reactivity which is primarily due to the presence of an α, β-unsaturated carbonyl system. At the same time, bicyclic monoterpenoids deserve special attention as a source of a key structural block or as one of the pharmacophore components of biologically active molecules. A series of new diarylpyrazoline derivatives based on isobornylchalcones with different substitutes (MeO, Hal, NO2, N(Me)2) was synthesized. Antioxidant properties of the obtained compounds were comparatively evaluated using in vitro model Fe2+/ascorbate-initiated lipid peroxidation in the substrate containing brain lipids of laboratory mice. It was demonstrated that the combination of the electron-donating group in the para-position of ring B and OH-group in the ring A in the structure of chalcone fragment provides significant antioxidant activity of synthesized diarylpyrazoline derivatives.

scholarly journals New species and records of Trichoderma isolated as mycoparasites and endophytes from cultivated and wild coffee in Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María del Carmen H. Rodríguez ◽  
Harry C. Evans ◽  
Lucas M. de Abreu ◽  
Davi M. de Macedo ◽  
Miraine K. Ndacnou ◽  
...  
Keyword(s):  
New Species ◽  
Cloud Forest ◽  
Elongation Factor ◽  
Classical Biological Control ◽  
Hemileia Vastatrix ◽  
Translation Elongation ◽  
Coffee Leaf Rust ◽  
Novel Taxa ◽  
Coffee Plants ◽  
Wild Coffee

AbstractA survey for species of the genus Trichoderma occurring as endophytes of Coffea, and as mycoparasites of coffee rusts (Hemileia), was undertaken in Africa; concentrating on Cameroon and Ethiopia. Ninety-four isolates of Trichoderma were obtained during this study: 76 as endophytes of healthy leaves, stems and berries and, 18 directly from colonized rust pustules. A phylogenetic analysis of all isolates used a combination of three genes: translation elongation factor-1α (tef1), rpb2 and cal for selected isolates. GCPSR criteria were used for the recognition of species; supported by morphological and cultural characters. The results reveal a previously unrecorded diversity of Trichoderma species endophytic in both wild and cultivated Coffea, and mycoparasitic on Hemileia rusts. Sixteen species were delimited, including four novel taxa which are described herein: T. botryosum, T. caeruloviride, T. lentissimum and T. pseudopyramidale. Two of these new species, T. botryosum and T. pseudopyramidale, constituted over 60% of the total isolations, predominantly from wild C. arabica in Ethiopian cloud forest. In sharp contrast, not a single isolate of Trichoderma was obtained using the same isolation protocol during a survey of coffee in four Brazilian states, suggesting the existence of a ‘Trichoderma void’ in the endophyte mycobiota of coffee outside of Africa. The potential use of these African Trichoderma isolates in classical biological control, either as endophytic bodyguards—to protect coffee plants from Hemileia vastatrix, the fungus causing coffee leaf rust (CLR)—or to reduce its impact through mycoparasitism, is discussed, with reference to the on-going CLR crisis in Central America.

scholarly journals Bioactive potential of natural biomaterials: identification, retention and assessment of biological properties

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kieran Joyce ◽  
Georgina Targa Fabra ◽  
Yagmur Bozkurt ◽  
Abhay Pandit
Keyword(s):  
Tissue Engineering ◽  
Therapeutic Potential ◽  
Biological Properties ◽  
Biological Assessment ◽  
Cross Linking ◽  
Natural Polymers ◽  
Drug Delivery Device ◽  
Biomedical Device ◽  
Wide Range ◽  
Bioactive Potential

AbstractBiomaterials have had an increasingly important role in recent decades, in biomedical device design and the development of tissue engineering solutions for cell delivery, drug delivery, device integration, tissue replacement, and more. There is an increasing trend in tissue engineering to use natural substrates, such as macromolecules native to plants and animals to improve the biocompatibility and biodegradability of delivered materials. At the same time, these materials have favourable mechanical properties and often considered to be biologically inert. More importantly, these macromolecules possess innate functions and properties due to their unique chemical composition and structure, which increase their bioactivity and therapeutic potential in a wide range of applications. While much focus has been on integrating these materials into these devices via a spectrum of cross-linking mechanisms, little attention is drawn to residual bioactivity that is often hampered during isolation, purification, and production processes. Herein, we discuss methods of initial material characterisation to determine innate bioactivity, means of material processing including cross-linking, decellularisation, and purification techniques and finally, a biological assessment of retained bioactivity of a final product. This review aims to address considerations for biomaterials design from natural polymers, through the optimisation and preservation of bioactive components that maximise the inherent bioactive potency of the substrate to promote tissue regeneration.

scholarly journals Hybrid Nanoassemblies from Viruses and DNA Nanostructures

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1413
Author(s):  
Sofia Ojasalo ◽  
Petteri Piskunen ◽  
Boxuan Shen ◽  
Mauri A. Kostiainen ◽  
Veikko Linko
Keyword(s):  
Cell Activation ◽  
Immune Cell ◽  
Dna Nanotechnology ◽  
Biological Properties ◽  
Dna Nanostructures ◽  
Dna Structures ◽  
Nanoscale Structures ◽  
Immune Cell Activation ◽  
Wide Range ◽  
Structural Dna Nanotechnology

Viruses are among the most intriguing nanostructures found in nature. Their atomically precise shapes and unique biological properties, especially in protecting and transferring genetic information, have enabled a plethora of biomedical applications. On the other hand, structural DNA nanotechnology has recently emerged as a highly useful tool to create programmable nanoscale structures. They can be extended to user defined devices to exhibit a wide range of static, as well as dynamic functions. In this review, we feature the recent development of virus-DNA hybrid materials. Such structures exhibit the best features of both worlds by combining the biological properties of viruses with the highly controlled assembly properties of DNA. We present how the DNA shapes can act as “structured” genomic material and direct the formation of virus capsid proteins or be encapsulated inside symmetrical capsids. Tobacco mosaic virus-DNA hybrids are discussed as the examples of dynamic systems and directed formation of conjugates. Finally, we highlight virus-mimicking approaches based on lipid- and protein-coated DNA structures that may elicit enhanced stability, immunocompatibility and delivery properties. This development also paves the way for DNA-based vaccines as the programmable nano-objects can be used for controlling immune cell activation.

NOM and MIB, who wins in the competition for activated carbon adsorption sites?

2004 ◽  
Vol 49 (9) ◽  
pp. 257-265 ◽  
Author(s):  
C. Hepplewhite ◽  
G. Newcombe ◽  
D.R.U. Knappe
Keyword(s):  
Molecular Weight ◽  
Activated Carbons ◽  
Background Concentration ◽  
Low Molecular Weight ◽  
Activated Carbon Adsorption ◽  
Microporous Carbons ◽  
Adsorption Sites ◽  
Carbon Adsorption ◽  
Competitive Mechanism ◽  
Wide Range

The adsorption of an odour compound common in drinking water, 2-methylisoborneol (MIB), was studied on two activated carbons in the presence of 13 well-characterised natural organic matter (NOM) solutions. It was found that, although the carbons and the NOM solutions had a wide range of characteristics, the major competitive mechanism was the same in all cases. The low molecular weight NOM compounds were the most competitive, participating in a direct competition with the MIB molecule for adsorption sites. Equivalent background concentration (EBC) calculations indicated a relatively low concentration of directly competing compounds in the NOM. Some evidence of pore restriction was also seen, with microporous carbons most affected by low molecular weight NOM, and mesoporous carbons impacted by the higher molecular weight compounds.

Bioencapsulation in Sol-Gel Glasses

1998 ◽  
Vol 519 ◽  
Author(s):  
L. Bergogne ◽  
S. Fennouh ◽  
J. Livage ◽  
C. Roux
Keyword(s):  
Sol Gel ◽  
Porous Silica ◽  
Silica Matrix ◽  
Whole Cells ◽  
The Past ◽  
Wide Range ◽  
Activity Of Enzymes ◽  
Gel Glasses ◽  
Micro Organisms

AbstractBioencapsulation in sol-gel materials has been widely studied during the past decade. Trapped species appear to retain their bioactivity in the porous silica matrix. Small analytes can diffuse through the pores allowing bioreactions to be performed in-situ, inside the sol-gel glass. A wide range of biomolecules and micro-organisms have been encapsulated. The catalytic activity of enzymes is used for the realization of biosensors or bioreactors. Antibody-antigen recognition has been shown to be feasible within sol-gel matrices. Trapped antibodies bind specifically the corresponding haptens and can be used for the detection of traces of chemicals. Even whole cells are now encapsulated without any alteration of their cellular organization. They can be used for the production of chemicals or as antigens for immunoassays.

Synthesis of 1,2,3–triazole compounds by click chemistry in aqueous medium and evaluation of bactericidal and antitumoral properties.

2021 ◽  
Vol 17 ◽  
Author(s):  
Lucas Lima Zanin ◽  
David Esteban Quintero Jimenez ◽  
Willian Garcia Birolli ◽  
Tiago Venâncio ◽  
Talita Alvarenga Valdes ◽  
...  
Keyword(s):  
Click Chemistry ◽  
Biological Properties ◽  
Antitumoral Activity ◽  
Biological Assays ◽  
Triazole Derivatives ◽  
Optimization Study ◽  
Water As Solvent ◽  
Wide Range ◽  
Screening Study ◽  
High Yields

Background: Triazoles are heterocyclic synthetic compounds that have gained relevance after studies by Sharpless on regioselective methodologies for the synthesis of 1,2,3-triazole derivatives. In addition, they have a wide range of biological properties. Objective: The objective of this study is to develop a synthetic methodology aligned with the principles of click chemistry for the synthesis of 1,2,3-triazole derivatives and verify the profile of these compounds in biological assays. Methods: Initially, a model reaction was selected and an optimization study involving synthetic conditions was carried out. Using the most efficient condition, a series of compounds was developed by the reactions between 2-azido-1-phenylethan-1-one derivatives and terminal alkynes. In sequence, bactericidal and antitumoral assays were performed. Results: It was possible to synthesise ten examples using water as a sustainable solvent, in 1 hour, with good yields of 73–99%, including three compounds described for the first time. Two products presented bactericidal activity, one against the gram-negative Escherichia coli ATCC 25922 and other against the gram-positive Paenibacillus alvei CBMAI 2221. Moreover, other two triazole derivatives presented antitumoral activity for prostate and pancreas cancer cells in this screening study with the bioactivity quantified for compound 1-([1,1'-biphenyl]-4-yl)-2-(4-(p-tolyl)-1H-1,2,3-triazol-1-yl)ethan-1-one (IC50 = 132 µM). Conclusion: Herein, an efficient methodology for the synthesis of 1,2,3-triazole derivatives with high yields and using water as solvent was developed. Furthermore, some compounds presented positive results to bactericidal and antitumoral assays, justifying further exploration of these novel compounds and their biological properties.

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