Haemolytic activity and cellular toxicity of SBA-15-type silicas: elucidating the role of the mesostructure, surface functionality and linker length

2015 ◽  
Vol 3 (13) ◽  
pp. 2714-2724 ◽  
Author(s):  
Małgorzata Ferenc ◽  
Nadia Katir ◽  
Katarzyna Miłowska ◽  
Mosto Bousmina ◽  
Jean-Pierre Majoral ◽  
...  

Haemolytic activity and cellular toxicity of native, amino-, mercapto-, and carboxy-terminated SBA-15-type silicates were investigated.

1980 ◽  
Vol 42 (1) ◽  
pp. 153-167
Author(s):  
S. Knutton ◽  
T. Bachi

The role of the haemolytic activity of Sendai virus in cell-cell fusion has been examined in monolayers of human erythrocytes and erythrocyte ghosts fused with either haemolytic or non-haemolytic virus. Morphological observations indicate that cell swelling and haemolysis is a distinct event in cell-cell fusion irrespective of whether it is virally induced or, in the case of non-haemolytic virus, experimentally induced. Osmotic swelling appears to be the driving force by which cells which have established sites of membrane fusion expand such sites to form poly-erythrocytes. Immunofluorescent labelling of viral antigens incorporated into the erythrocyte membrane as a result of viral envelope-cell fusion indicates that diffusion of antigens in the plane of the membrane is restricted in intact erythrocytes and resealed erythrocyte ghosts but not in haemolysed erythrocytes or unsealed ghosts. A perturbation of the erythrocyte membrane resulting from osmotic lysis appears to form a prerequisite for the lateral diffusion of viral elements.


2013 ◽  
Vol 30 (12) ◽  
pp. 2228-2234 ◽  
Author(s):  
Mohammad Asadullah ◽  
Mohammad Shajahan Kabir ◽  
Mohammad Boshir Ahmed ◽  
Nadiah Abdul Razak ◽  
Nurul Suhada Abdur Rasid ◽  
...  

2019 ◽  
Vol 71 (2) ◽  
pp. 520-542 ◽  
Author(s):  
Zhixiang Jiang ◽  
Fei Lian ◽  
Zhenyu Wang ◽  
Baoshan Xing

Abstract Biochar is a promising soil additive for use in support of sustainable crop production. However, the high level of heterogeneity in biochar properties and the variations in soil composition present significant challenges to the successful uptake of biochar technologies in diverse agricultural soils. An improved understanding of the mechanisms that contribute to biochar–soil interactions is required to address issues related to climate change and cultivation practices. This review summarizes biochar modification approaches (physical, chemical, and biochar-based organic composites) and discusses the potential role of biochar in sustainable crop production and soil resiliency, including the degradation of soil organic matter, the improvement of soil quality, and reductions in greenhouse gas emissions. Biochar design is crucial to successful soil remediation, particularly with regard to issues arising from soil structure and composition related to crop production. Given the wide variety of feedstocks for biochar production and the resultant high surface heterogeneity, greater efforts are required to optimize biochar surface functionality and porosity through appropriate modifications. The design and establishment of these approaches and methods are essential for the future utilization of biochar as an effective soil additive to promote sustainable crop production.


2015 ◽  
Vol 4 (6) ◽  
Author(s):  
Athanasia Kostopoulou ◽  
Alexandros Lappas

AbstractMagnetic particles of optimized nanoscale dimensions can be utilized as building blocks to generate colloidal nanocrystal assemblies with controlled size, well-defined morphology, and tailored properties. Recent advances in the state-of-the-art surfactant-assisted approaches for the directed aggregation of inorganic nanocrystals into cluster-like entities are discussed, and the synthesis parameters that determine their geometrical arrangement are highlighted. This review pays attention to the enhanced physical properties of iron oxide nanoclusters, while it also points to their emerging collective magnetic response. The current progress in experiment and theory for evaluating the strength and the role of intra- and inter-cluster interactions is analyzed in view of the spatial arrangement of the component nanocrystals. Numerous approaches have been proposed for the critical role of dipole-dipole and exchange interactions in establishing the nature of the nanoclusters’ cooperative magnetic behavior (be it ferromagnetic or spin-glass like). Finally, we point out why the purposeful engineering of the nanoclusters’ magnetic characteristics, including their surface functionality, may facilitate their use in diverse technological sectors ranging from nanomedicine and photonics to catalysis.


2010 ◽  
Vol 45 (3) ◽  
pp. 359-365 ◽  
Author(s):  
Nehad Nasef ◽  
Rosetta Belcastro ◽  
Andrea Nash ◽  
Rosine Bishara ◽  
Dolores Iaboni ◽  
...  

1997 ◽  
Vol 325 (3) ◽  
pp. 685-691 ◽  
Author(s):  
Desong CHEN ◽  
R. Manjunatha KINI ◽  
Raymond YUEN ◽  
Hoon Eng KHOO

Stonustoxin (SNTX) is a two-subunit protein toxin purified from the venom of the stonefish (Synanceja horrida), which induces potent haemolytic activity. We examined the pore-forming property of this non-enzymic protein by an osmotic protection assay. SNTX-induced haemolysis was completely prevented by osmotic protectants of adequate size [poly(ethylene) glycol 3000; molecular diameter approx. 3.2 nm]. Uncharged molecules of smaller size, such as raffinose and poly(ethylene) glycol 1000–2000, failed to protect against cell lysis. These findings indicate that SNTX induces the formation of hydrophilic pores in the cell membrane, which results in the lysis of erythrocytes. Since cationic residues contribute significantly to the cytolytic activity of several other pore-forming toxins, we examined the role of positively charged lysine and arginine residues in the haemolytic activity of SNTX. SNTX lost its haemolytic activity when the positively charged side chains of lysine residues were neutralized or converted into negatively charged side chains upon carbamylation or succinylation respectively. The haemolytic activity of SNTX was also inhibited by the modification of positively charged arginine residues using 2,3-butanedione. The loss of haemolysis showed strong correlation with the number of Lys or Arg residues modified. CD analyses, however, showed that the conformation of SNTX was not significantly affected by these chemical modifications. Further, the haemolytic activity of SNTX was competitively inhibited by various negatively charged lipids, such as phosphatidylserine, cardiolipin and monosialogangliosides. These results indicate that SNTX induces potent haemolytic activity through the formation of pores in the cell membrane, and that cationic residues play a crucial role in its cytolytic mechanism.


2014 ◽  
Vol 6 (10) ◽  
pp. 7607-7614 ◽  
Author(s):  
Hui Zhou ◽  
Jagjit Nanda ◽  
Surendra K. Martha ◽  
Raymond R. Unocic ◽  
Harry M. Meyer ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jenny Clarke ◽  
Murielle Baltazar ◽  
Mansoor Alsahag ◽  
Stavros Panagiotou ◽  
Marion Pouget ◽  
...  

AbstractGroup A Streptoccocus (GAS) is among the most diverse of all human pathogens, responsible for a range of clinical manifestations, from mild superficial infections such as pharyngitis to serious invasive infections such as necrotising fasciitis and sepsis. The drivers of these different disease phenotypes are not known. The GAS cholesterol-dependent cytolysin, Streptolysin O (SLO), has well established cell and tissue destructive activity. We investigated the role of SLO in determining disease outcome in vivo, by using two different clinical lineages; the recently emerged hypervirulent outbreak emm type 32.2 strains, which result in sepsis, and the emm type 1.0 strains which cause septic arthritis. Using clinically relevant in vivo mouse models of sepsis and a novel septic arthritis model, we found that the amount and activity of SLO was vital in determining the course of infection. The emm type 32.2 strain produced large quantities of highly haemolytic SLO that resulted in rapid development of sepsis. By contrast, the reduced concentration and lower haemolytic activity of emm type 1.0 SLO led to translocation of bacteria from blood to joints. Importantly, sepsis associated strains that were attenuated by deletion or inhibition of SLO, then also translocated to the joint, confirming the key role of SLO in determining infection niche. Our findings demonstrate that SLO is key to in vivo phenotype and disease outcome. Careful consideration should be given to novel therapy or vaccination strategies that target SLO. Whilst neutralising SLO activity may reduce severe invasive disease, it has the potential to promote chronic inflammatory conditions such as septic arthritis.


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