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Life ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 123
Astra Piccinini ◽  
Eva C. Lourenço ◽  
Osvaldo S. Ascenso ◽  
Maria Rita Ventura ◽  
Heinz Amenitsch ◽  

Many proteins are usually not stable under different stresses, such as temperature and pH variations, mechanical stresses, high concentrations, and high saline contents, and their transport is always difficult, because they need to be maintained in a cold regime, which is costly and very challenging to achieve in remote areas of the world. For this reason, it is extremely important to find stabilizing agents that are able to preserve and protect proteins against denaturation. In the present work, we investigate, by extensively using synchrotron small-angle X-ray scattering experiments, the stabilization effect of five different sugar-derived compounds developed at ExtremoChem on two model proteins: myoglobin and insulin. The data analysis, based on a novel method that combines structural and thermodynamic features, has provided details about the physical-chemical processes that regulate the stability of these proteins in the presence of stabilizing compounds. The results clearly show that some modified sugars exert a greater stabilizing effect than others, being able to maintain the active forms of proteins at temperatures higher than those in which proteins, in the absence of stabilizers, reach denatured states.

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 483
Sorin David ◽  
Mihaela Gheorghiu ◽  
Sanaa Daakour ◽  
Raluca-Elena Munteanu ◽  
Cristina Polonschii ◽  

Cross linked gold-dynamic constitutional frameworks (DCFs) are functional materials of potential relevance for biosensing applications, given their adaptivity and high responsivity against various external stimuli (such as pH, temperature) or specific interactions with biomolecules (enzymes or DNA) via internal constitutional dynamics. However, characterization and assessment of their dynamic conformational changes in response to external stimuli has never been reported. This study proves the capability of Surface Plasmon Resonance (SPR) assays to analyse the adaptive structural modulation of a functional matrix encompassing 3D gold-dynamic constitutional frameworks (Au-DCFs) when exposed to pH variations, as external stimuli. We analyse Au-DCFs formed from Au nanoparticles, (AuNP) connected through constitutionally dynamic polymers, dynamers, with multiple functionalities. For increased generality of this proof-of-concept assay, Au-DCFs, involving DCFs designed from 1,3,5-benzene-tricarbaldehyde (BTA) connecting centres and polyethylene glycol (PEG) connectors, are covalently attached to standard SPR sensing chips (Au nanolayers, carboxyl terminated or with carboxymethyl dextran, CMD top-layer) and analysed using state-of-the art SPR instrumentation. The SPR effects of the distance from the Au-DCFs matrix to the Au nanolayer of the sensing chip, as well as of Au-DCFs thickness were investigated. This study reveals the SPR response, augmented by the AuNP, to the conformational change, i.e., shrinkage, of the dynamer and AuNP matrix when decreasing the pH, and provides an unexplored insight into the sensing applicability of SPR real-time analysis of adaptive functional materials.

Lawal-Are A.O. ◽  
Moruf R.O. ◽  
Olaniyi I.O. ◽  
Okafor D.S.

The biological response to chemical pollutants reflects the acid–base status of an aquatic ecosystem. The gercacinid, Cardiosoma armatum (75±0.1 g) was exposed to acidified waters to evaluate the effects on its immune parameters. The crabs were exposed to pH 4.0, 5.0, 6.0 and 7.8 (control) for 28 days. The hematological parameters of control crabs and crabs exposed to varied doses of acidified water indicated a marked reduction. Significant (p<0.05) higher alkaline phosphatase and albumen were obtained in pH 4.0, 5.0 and 6.0 compared to control; other values were mostly similar to control. The highest superoxide dismutase (SOD) (252.61±0.06 min/mg pro) was recorded in control group, while highest CAT activity (2.08±0.16 min/mg protein) was recorded in crabs exposed to pH 4 treatment. Furthermore, the control group's SOD activity was significantly higher than the exposed groups. With a lower pH, the quantities of malondialdehyde increased substantially and were significantly different from the control group. While these findings demonstrate that changes in pH have limited impact on energy use, decreasing immune system conditions show that C. armatum is susceptible to pH variations and may be influenced in aquaculture, where a pH drop is more prominent.

2021 ◽  
Vol 193 (12) ◽  
Nicholas Metherall ◽  
Elisabeth Holland ◽  
Sara Beavis ◽  
Adi Mere Dralolo Vinaka

AbstractWithin Pacific Small Island Developing States (Pacific SIDS), the ridge-to-reef (R2R) approach has emerged as a framework for monitoring river connectivity between terrestrial and marine ecosystems. The study measured water quality, including pH, over 88.40 km of the Ba River in Fiji. The sampling design focused on measuring spatio-temporal variability in pH throughout the sugarcane season with three rapid sampling periods (RSP1, 2 & 3) along the Ba River, together with continuous measurement of temperature and pH using stationary data loggers at two locations upstream and downstream of the sugar mill. Spatial variability in pH and water quality was characterised before (RSP1 and RSP2) and during (RSP3) the sugarcane season. Mean pH measured before the sugarcane crushing season for RSP1 and RSP2 were 8.16 (± 0.49) and 8.20 (± 0.61) respectively. During the sugarcane crushing season (RSP3), mean pH declined by 3.06 units to 6.94 within 42 m downstream of the sugar mill (P ≤ 0.001). The 3.06 unit decline in pH for RSP3 exceeded both the mean diurnal variation in pH of 0.39 and mean seasonal variation in pH of 2.01. This decline in pH could be a potential source of acidification to downstream coastal ecosystems with implications for coral reefs, biodiversity and fishery livelihoods.

Jurnal Tekno ◽  
2021 ◽  
Vol 18 (2) ◽  
pp. 62-70
Netty Herawati - ◽  
Muhamad Rafiqy ◽  
Kiagus Rahmad Roni ◽  
Heni Juniar

Industrial waste can cause environmental pollution, one of which is solid metal waste.  Lead is a dangerous and toxic heavy metal that can cause damage to the surrounding environment. Liquid waste containing mercury in industry contains a mixture of chemical compounds that other This causes the pH of the solution in the waste to vary. Lead metal waste needs to be treated with method one of which is the absorption of waste using an adsorbent. To enlarge the pores, the adsorbent will be activated using a 2 M KOH solution with the selected adsorbent, namely the sewage sludge of PDAM Tirta Musi Palembang which contains PAC (Poly Aluminum Chloride) which can help optimize absorption. The level of metal degradation was analyzed using AAS with absorption parameters obtained 4 with an absorption capacity of 23 ,22 mg/g.

2021 ◽  
Vol 924 (1) ◽  
pp. 012088
R N Sari ◽  
E Sinurat ◽  
D L Ayudiarti ◽  
D A Oktavia

Abstract The potential of green seaweed Caulerpa sp. as a reducing agent, stabilizer, and capping agent and the benefits of zinc oxide (ZnO) nanoparticles in the food and non-food is exciting to be developed. The research was aimed to understand the potential of green seaweed (Caulerpa sp.) to become ZnO nanoparticles capping agent with ten mM zinc nitrate as a precursor and pH variations of 8-12. The analysis included function groups, particle size distribution, and % mass O and Zn composition. The result found that spectra at wave number 574 cm−1 were Zn-O stretching vibration from solution pH synthesis of 11. Size distribution was homogeneous, but it still had not met the size of nano. The average particle size ranged from 992.37-1369.36 nm, and the smallest particle size was obtained at a ZnO synthesized at a pH of 8. The composition from ZnO synthesis at solution pH of 9 was 7.68% O and 92.32% Zn. Caulerpa sp. extract could produce a synthesis of ZnO with ten mM zinc nitrate as a precursor and solution pH variations. Although the biosynthesis had not produced a ZnO with nanoparticles size yet, the particle size distribution had been homogeneous. The biosynthesis at pH 9, %mass Zn and O for ZnO produced had been similar to the ZnO standard.

2021 ◽  
Vol 16 (4) ◽  
pp. 847-856
Ni Made Wiratini ◽  
Triyono Triyono ◽  
Wega Trisunaryanti ◽  
Agus Kuncaka

Graphite/NiO/Ni electrode had been fabricated for the electro-oxidation of remazol black 5 dye. The electrode was synthesized by electrodeposition method. Electro-oxidation of 100 ppm remazol black 5 dye was carried out at various concentrations of NaCl, 0.025; 0.05; 0.1; 0.25; and 0.5 M, variations in electro-oxidation time were 15, 30, 45, and 60 minutes, and pH variations were 4, 6, and 8. Cyclic voltammetry test revealed that graphite/NiO/Ni electrode had higher electrocatalytic capability compared to graphite electrode. The X-ray diffraction (XRD) patterns showed the decreasing value of 2θ from 44.6° for Ni to 43.5° for NiO. Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) showed that NiO/Ni deposited on the graphite surface in the form of solid grains and cracks, FTIR showed that δ(Ni−O) bond appeared at 582–511 cm−1. The decolorization efficiency of remazol black 5 for graphite/NiO/Ni electrode was 100% for 45 minutes of the electro-oxidation process, while the decolorization efficiency of remazol black 5 for graphite electrode was 99.74% for 60 minutes of the electro-oxidation process. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License ( 

Silviu-Laurentiu Badea ◽  
Diana-Ionela Stegarus ◽  
Violeta-Carolina Niculescu ◽  
Stanica Enache ◽  
Amalia Soare ◽  

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 191
Ana Carolina P. Afonso ◽  
Ana Salomé Correia ◽  
Diana Duarte ◽  
Ana T. S. C. Brandão ◽  
Maria del Valle Martínez de Yuso ◽  

Here we report the rational development of a carbon dot (CDs)-based fluorescent pH nanosensor by employing an active surface preservation strategy. More specifically, citric acid, urea and fluorescein were subjected to a one-pot hydrothermal treatment, which preserved fluorescein-like structures on the surface of the CDs. The obtained CDs showed pH-sensitive green emission, which can be used to determine pH variations from 3.7 to 12.1 by fluorescence enhancement. Moreover, the obtained nanoparticles showed excellent selectivity toward pH, fluorescence reversibility in different pH values, photostability, while being compatible with human cell lines (even at high concentrations). Furthermore, their performance as pH sensors was comparable with reference pH determination procedures. Thus, an active surface preservation strategy was successfully employed to develop fluorescence pH nanosensors in a rational manner and without post-synthesis functionalization strategies, which show potential for future use in pH determination.

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