scholarly journals New Factors Enhancing the Reactivity of Cysteines in Molten Globule-Like Structures

2020 ◽  
Vol 21 (18) ◽  
pp. 6949
Author(s):  
Giorgia Gambardella ◽  
Giada Cattani ◽  
Alessio Bocedi ◽  
Giorgio Ricci
Keyword(s):  
Electrostatic Interactions ◽  
Molten Globule ◽  
Disulfide Exchange ◽  
Disulfide Formation ◽  
Ph Values ◽  
New Findings ◽  
Thiol Reagent ◽  
Protein Functions ◽  
Complex Formations ◽  
First Time

Protein cysteines often play crucial functional and structural roles, so they are emerging targets to design covalent thiol ligands that are able to modulate enzyme or protein functions. Some of these residues, especially those involved in enzyme mechanisms—including nucleophilic and reductive catalysis and thiol-disulfide exchange—display unusual hyper-reactivity; such a property is expected to result from a low pKa and from a great accessibility to a given reagent. New findings and previous evidence clearly indicate that pKa perturbations can only produce two–four-times increased reactivity at physiological pH values, far from the hundred and even thousand-times kinetic enhancements observed for some protein cysteines. The data from the molten globule-like structures of ribonuclease, lysozyme, bovine serum albumin and chymotrypsinogen identified new speeding agents, i.e., hydrophobic/electrostatic interactions and productive complex formations involving the protein and thiol reagent, which were able to confer exceptional reactivity to structural cysteines which were only intended to form disulfides. This study, for the first time, evaluates quantitatively the different contributions of pKa and other factors to the overall reactivity. These findings may help to clarify the mechanisms that allow a rapid disulfide formation during the oxidative folding of many proteins.

Materials to the lichen flora of Samurskiy Ridge (high mountainous Dagestan)

2018 ◽  
Vol 52 (2) ◽  
pp. 397-406
Author(s):  
A. B. Ismailov ◽  
G. P. Urbanavichus
Keyword(s):  
North Caucasus ◽  
Lichenicolous Fungi ◽  
Greater Caucasus ◽  
Altitudinal Range ◽  
The North ◽  
New Findings ◽  
Mountainous Landscapes ◽  
First Time ◽  
Lichen Flora

The lichens and lichenicolous fungi of high mountainous landscapes of Samurskiy Ridge were studied in altitudinal range 2400–3770 m a. s. l. for the first time and 112 species are recorded. Among them 33 species, 10 genera (Arthrorhaphis, Baeomyces, Calvitimela, Epilichen, Lambiella, Psorinia, Rufoplaca, Sagedia, Sporastatia, Tremolecia) and 4 families (Anamylopsoraceae, Arthrorhaphidaceae, Baeomycetaceae, Hymeneliaceae) are new for Dagestan, six species (Buellia uberior, Carbonea atronivea, Lecanora atrosulphurea, Lecidea fuliginosa, L. swartzioidea, Rhizoplaca subdiscrepans) are reported for the first time for the Greater Caucasus and two species (Acarospora subpruinata and Rhizocarpon postumum) — for the North Caucasus. Most of the new findings were collected from 3500–3770 m a. s. l.

Rekonstruktion des Ursprungs und Neudatierung zweier magischer Gemmen mit Hilfe einer Zauberzeichensequenz

2020 ◽  
Vol 147 (2) ◽  
pp. 153-163
Author(s):  
Kirsten Dzwiza
Keyword(s):  
Comparative Study ◽  
Fine Arts ◽  
17Th Century ◽  
The State ◽  
Roman Period ◽  
16Th Century ◽  
New Findings ◽  
State Museum ◽  
Museum Of Fine Arts ◽  
First Time

SummaryThere are only a few sequences of ancient magic signs known to us today that have been preserved on multiple artefacts. A previously unnoticed sequence of 17 signs on a gem in the Museum of Fine Arts in Vienna occurs with minor but significant variations on two other gems in the State Museum of Egyptian Art in Munich. The Viennese gem is dated to the 16th century and is documented as a drawing in a 17th century publication. The first Munich gem has been assigned to the Graeco-Roman period. The second gem, which, according to the inventory card of the museum, also belongs to the Graeco-Roman period, is published here for the first time. A comparative study of the three gems and the drawing has lead to a number of new findings, including the re-dating of the Munich gems.

scholarly journals Bioactive Compounds in Salicornia patula Duval-Jouve: A Mediterranean Edible Euhalophyte

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 410
Author(s):  
Irene Sánchez-Gavilán ◽  
Esteban Ramírez ◽  
Vicenta de la Fuente
Keyword(s):  
Fatty Acids ◽  
Bioactive Compounds ◽  
Mediterranean Area ◽  
Biological Properties ◽  
Total Phenolic ◽  
Tinto River ◽  
New Findings ◽  
High Concentrations ◽  
Salicornia Patula ◽  
First Time

Many halophytes have great nutritional and functional potential, providing chemical compounds with biological properties. Salicornia patula Duval-Jouve is a common euhalophyte from saline Mediterranean territories (Spain, Portugal, France, and Italy). In the present work we quantified for the first time the bioactive compounds in S. patula (total phenolic compounds and fatty acids), from Iberian Peninsula localities: littoral-coastal Tinto River basin areas (southwest Spain, the Huelva province), and mainland continental territories (northwest and central Spain, the Valladolid and Madrid provinces). Five phenolic acids including caffeic, coumaric, veratric, salicylic, and transcinnamic have been found with differences between mainland and coastal saltmarshes. S. patula contain four flavonoids: quercetin-3-O-rutinoside, kaempferol/luteolin, apigenin 7-glucoside, and pelargonidin-3-O-rutinoside. These last two glycosylated compounds are described for the first time in this genus of Chenopodiaceae. The fatty acid profile described in S. patula stems contains palmitic, oleic, and linoleic acids in high concentrations, while stearic and long-chain fatty acids were detected in low amounts. These new findings confirm that S. patula is a valuable source of bioactive compounds from Mediterranean area.

scholarly journals Hybrid Acrylated Chitosan and Thiolated Pectin Cross-Linked Hydrogels with Tunable Properties

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 266
Author(s):  
Shaked Eliyahu ◽  
Alexandra Galitsky ◽  
Esther Ritov ◽  
Havazelet Bianco-Peled
Keyword(s):  
Electrostatic Interactions ◽  
Profile Analysis ◽  
Hybrid Hydrogel ◽  
Texture Profile ◽  
Ph Values ◽  
X Ray Scattering ◽  
Wide Range ◽  
Michael Type Addition ◽  
Physical And Chemical ◽  
Hydrogel System

We developed and characterized a new hydrogel system based on the physical and chemical interactions of pectin partially modified with thiol groups and chitosan modified with acrylate end groups. Gelation occurred at high pectin thiol ratios, indicating that a low acrylated chitosan concentration in the hydrogel had a profound effect on the cross-linking. Turbidity, Fourier transform infrared spectroscopy, and free thiol determination analyses were performed to determine the relationships of the different bonds inside the gel. At low pH values below the pKa of chitosan, more electrostatic interactions were formed between opposite charges, but at high pH values, the Michael-type addition reaction between acrylate and thiol took place, creating harder hydrogels. Swelling experiments and Young’s modulus measurements were performed to study the structure and properties of the resultant hydrogels. The nanostructure was examined using small-angle X-ray scattering. The texture profile analysis showed a unique property of hydrogel adhesiveness. By implementing changes in the preparation procedure, we controlled the hydrogel properties. This hybrid hydrogel system can be a good candidate for a wide range of biomedical applications, such as a mucosal biomimetic surface for mucoadhesive testing.

scholarly journals A “molten globule” of Torpedo acetylcholinesterase undergoes thiol-disulfide exchange.

1994 ◽  
Vol 269 (48) ◽  
pp. 30093-30096
Author(s):  
J Eichler ◽  
D.I. Kreimer ◽  
L Varon ◽  
I Silman ◽  
L Weiner
Keyword(s):  
Molten Globule ◽  
Disulfide Exchange

scholarly journals Notes on protected and threatened plants in Castilla y León (North-West Spain)

2020 ◽  
Vol 41 (2) ◽  
pp. 213-220
Author(s):  
Fermín Del Egido ◽  
Patricio Bariego ◽  
Alberto Rodríguez ◽  
María Santos Vicente
Keyword(s):  
Plant Species ◽  
New Records ◽  
Vascular Plant ◽  
Geographic Range ◽  
Threatened Plants ◽  
North West ◽  
Castilla Y Leon ◽  
Vascular Plant Species ◽  
New Findings ◽  
First Time

We provide new records and notes on 25 protected and/or threatened vascular plant species in Castilla y León. Some of them illustrate not only new findings but also an interesting expansion of their geographic range. Eight taxa are reported for the first time in some provinces, while eleven of them were two or three times previously reported.

Three new species and four new species records of earthworms of the genus Moniligaster Perrier, 1872 (Clitellata: Moniligastridae) from Kerala region of the Western Ghats Biodiversity Hotspot, India

Zootaxa ◽  
2021 ◽  
Vol 4949 (2) ◽  
pp. 381-397
Author(s):  
S. PRASANTH NARAYANAN ◽  
S. SATHRUMITHRA ◽  
R. ANUJA ◽  
G. CHRISTOPHER ◽  
A.P. THOMAS ◽  
...  
Keyword(s):  
New Species ◽  
Original Description ◽  
Biodiversity Hotspot ◽  
Andaman Islands ◽  
Peninsular India ◽  
New Findings ◽  
Indian State ◽  
Three New Species ◽  
First Time ◽  
The Western Ghats

Three new species of Moniligaster Perrier, 1872, namely M. bahli Narayanan & Julka, sp. nov., M. blakemorei Narayanan & Julka, sp. nov. and M. keralensis Narayanan & Julka, sp. nov. are described from materials collected from the Indian state of Kerala. Moniligaster cernosvitovi Gates, 1962, Moniligaster horsti Gates, 1940, Moniligaster michaelseni Gates, 1940 and Moniligaster stephensoni Gates, 1940 are recorded for the first time from the state. With the new findings, a total of 10 Moniligaster species are known from Kerala. Moniligaster species are restricted to southern peninsular India, except Moniligaster ivaniosi Manazhy, 2011, decribed from the Andaman Islands, outside the currently known distributional range of the genus. Hence we critically reviewed the original description and reinvestigated the holotype. As a result, Moniligaster ivaniosi is considered a junior synonym of Drawida nepalensis Michaelsen, 1907. 

scholarly journals Oxaliplatin–Biomimetic Magnetic Nanoparticle Assemblies for Colon Cancer-Targeted Chemotherapy: An In Vitro Study

Pharmaceutics ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 395 ◽  
Author(s):  
Ylenia Jabalera ◽  
Beatriz Garcia-Pinel ◽  
Raul Ortiz ◽  
Guillermo Iglesias ◽  
Laura Cabeza ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Electrostatic Interactions ◽  
Magnetic Nanoparticle ◽  
In Vitro Study ◽  
Targeted Chemotherapy ◽  
Proof Of Concept ◽  
Therapeutic Approaches ◽  
Ph Values ◽  
Common Cancer

Conventional chemotherapy against colorectal cancer (CRC), the third most common cancer in the world, includes oxaliplatin (Oxa) which induces serious unwanted side effects that limit the efficiency of treatment. Therefore, alternative therapeutic approaches are urgently required. In this work, biomimetic magnetic nanoparticles (BMNPs) mediated by MamC were coupled to Oxa to evaluate the potential of the Oxa–BMNP nanoassembly for directed local delivery of the drug as a proof of concept for the future development of targeted chemotherapy against CRC. Electrostatic interactions between Oxa and BMNPs trigger the formation of the nanoassembly and keep it stable at physiological pH. When the BMNPs become neutral at acidic pH values, the Oxa is released, and such a release is greatly potentiated by hyperthermia. The coupling of the drug with the BMNPs improves its toxicity to even higher levels than the soluble drug, probably because of the fast internalization of the nanoassembly by tumor cells through endocytosis. In addition, the BMNPs are cytocompatible and non-hemolytic, providing positive feedback as a proof of concept for the nanoassembly. Our study clearly demonstrates the applicability of Oxa–BMNP in colon cancer and offers a promising nanoassembly for targeted chemotherapy against this type of tumor.

scholarly journals High-Efficiency Catalysis of Peroxymonosulfate by MgO for the Degradation of Organic Pollutants

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Qian Peng ◽  
Xuekun Tang ◽  
Kun Liu ◽  
Xianping Luo ◽  
Dongsheng He ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Organic Pollutants ◽  
High Efficiency ◽  
The Novel ◽  
Ph Values ◽  
Interesting Insight ◽  
Wide Range ◽  
First Time ◽  
Insight Into ◽  
Single Factor Experiment

In the study, magnesium oxide (MgO) was used to catalyze peroxymonosulfate (PMS) for the degradation of organic pollutants for the first time. According to the single-factor experiment results, it was determined that MgO could efficiently catalyze PMS to degrade organic matters in a wide range of pH values. Based on radical quenching experiments and electron spinning resonance spectra, singlet oxygen was identified to be the crucial reactive species. Importantly, the oxygen vacancy on the surface of MgO was determined as the key active site, which accelerated the decomposition of PMS to produce singlet oxygen. This study provides an interesting insight into the novel and ignored catalyst of MgO for the highly efficient activation of PMS, which will greatly benefit the Fenton-like catalytic degradation of organic wastewater.

scholarly journals Study of the Adhesion Mechanism of Acidithiobacillus ferrooxidans to Pyrite in Fresh and Saline Water

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 306 ◽  
Author(s):  
Francisca San Martín ◽  
Claudio Aguilar
Keyword(s):  
Fresh Water ◽  
Electrostatic Interactions ◽  
Saline Water ◽  
Streaming Potential ◽  
Bacterial Attachment ◽  
Van Der Waals Interactions ◽  
Streaming Potentials ◽  
Ph Values ◽  
Na Ions ◽  
Kinetics Of

In the present work, the streaming potential of A. ferrooxidans and pyrite was measured in two environments: fresh and saline water (water with 35 g/L of NaCl) at different pH values. Also, attachment kinetics of A. ferrooxidans to pyrite was studied in fresh and saline water at pH 4. The results show that A. ferrooxidans and pyrite had lower streaming potentials (comparing absolute values) in saline water than in fresh water, indicating the compression in the electrical double layer caused by Cl− and Na+ ions. It was also determined that the bacteria had a higher level of attachment to pyrite in fresh water than in saline water. The high ionic strength of saline water reduced the attractive force between A. ferrooxidans and pyrite, which in turn reduced bacterial attachment. Electrostatic interactions were determined to be mainly repulsive, since the bacteria and mineral had the same charge at pH 4. Despite this, the bacteria adhered to pyrite, indicating that hydrophobic attraction forces and Lifshitz–van der Waals interactions were stronger than electrostatic interactions, which caused the adhesion of A. ferrooxidans to pyrite.

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