Polymers in small-interfering RNA delivery

This review will cover the current strategies that are being adopted to efficiently deliver small interfering RNA using nonviral vectors, including the use of polymers such as polyethylenimine, poly(lactic-co-glycolic acid), polypeptides, chitosan, cyclodextrin, dendrimers, and polymers-containing different nanoparticles. The article will provide a brief and concise account of underlying principle of these polymeric vectors and their structural and functional modifications which were intended to serve different purposes to affect efficient therapeutic outcome of small-interfering RNA delivery. The modifications of these polymeric vectors will be discussed with reference to stimuli-responsiveness, target specific delivery, and incorporation of nanoconstructs such as carbon nanotubes, gold nanoparticles, and silica nanoparticles. The emergence of small-interfering RNA as the potential therapeutic agent and its mode of action will also be mentioned in a nutshell.     

Isolation of a <Emphasis Type="Italic">Pseudomonas</Emphasis><Emphasis Type="Italic">aeruginosa</Emphasis> strain from soil that can degrade polyurethane diol

Polyurethane diol (PUR-diol), a synthetic polymer, is widely used as a modifier for water-soluble resins and emulsions in wood appliances and auto coatings. Non-biodegradability of polyurethanes (PUR) and PUR-based materials poses a threat to environment that has led scientists to isolate microbes capable of degrading PUR. However, the bio-degradation of PUR-diol has not yet been reported. In this study, we report isolation of a soil bacterium that can survive using PUR-diol as sole carbon source. PUR-diol degradation by the organism was confirmed by thin layer chromatographic analysis of the conditioned medium obtained after the growth wherein a significant reduction of PUR-diol was observed compared to non-inoculated medium. To quantify the PUR-diol degradation, a sensitive assay based on High Performance Thin Layer Chromatography has been developed that showed 32% degradation of PUR-diol by the organism in 10 days. Degradation kinetics showed the maximal depletion of PUR-diol during logarithmic growth of the organism indicating a direct relation between the growth and PUR-diol degradation. Mutagenic study and GC-MS analysis revealed that esterase activity is involved in this degradation event. The ribotyping and metabolic fingerprinting analysis showed that this organism is a strain of Pseudomonous aeruginosa (P. aeruginosa). It has also been observed that this strain is able to degrade Impranil DLN™, a variety of commercially available PUR. Therefore this study identifies a new bacterium from soil that has the potential to reduce PUR-related waste burden and adds a new facet to diverse functional activities of P. aeruginosa.     

Role of vitamin D in treating COVID-19-associated coagulopathy: problems and perspectives

Molecular and Cellular Biochemistry - Aggressive inflammatory response leading to hypercoagulability has been found to be associated with disease severity in COVID-19 patients and portends bad...     

Source-Sink Relationship: Control of Photosynthesis in the Flag Leaf by the Panicle in Wheat

If the sink organs regulate the metabolic activity of the sourceorgans through the transmission of a signal and that signalis chemical in nature, then it should be present among the substancescoming out of the panicle. When flag leaf respiration and photosynthesisof wheat (Tritcum aestivum L.) cv. HP 1459 were measured withan infrared gas analyser after feeding the flag leaves withthe diffusate coming out of the panicle, it was observed thatwhile respiration was unaffected, photosynthesis was sharplyinhibited; the inhibition decreased with increasing age of thepanicle. Among the known plant growth regulators none couldsatisfy the requirements of this role with the exception ofabscisic acid which was found to inhibit photosynthesis by morethan 50% even at 10^–7 M, when respiration was affectedby only 8%. Apparently, abscisic acid inhibited photosynthesisthrough its effects on stomatal movement. (Received September 2, 1986; Accepted May 1, 1987)     

Exploring geometric properties of gold nanoparticles using TEM images to explain their chaperone like activity for citrate synthase

Study on geometric properties of nanoparticles and their relation with biomolecular activities, especially protein is quite a new field to explore. This work was carried out towards this direction where images of gold nanoparticles obtained from transmission electron microscopy were processed to extract their size and area profile at different experimental conditions including and excluding a protein, citrate synthase. Since the images were ill-posed, texture of a context-window for each pixel was used as input to a back-propagation network architecture to obtain decision on its membership as nanoparticle. The segmented images were further analysed by k-means clustering to derive geometric properties of individual nanoparticles even from their assembled form. The extracted geometric information was found to be crucial to give a model featuring porous cage like configuration of nanoparticle assembly using which the chaperone like activity of gold nanoparticles can be explained.     

Multispectroscopic studies on the molecular interactions between bovine γ-globulin and borohydride-capped silver nanoparticles

Interactions between bovine γ-globulin (BGG) and borohydride-capped silver nanoparticles (BAgNPs) were studied using dynamic light scattering (DLS) and spectroscopic techniques such as UV–vis spectroscopy, fluorescence, and circular dichroism. The results were compared with earlier reported interactions between γ-globulin and citrate-coated AgNPs (CAgNPs). BAgNPs were synthesized and characterized. Irrespective of the coating on AgNPs, nanoparticles had formed ground-state complexes with the protein. CAgNPs, as well as BAgNPs had caused static quenching of tryptophan (Trp) fluorescence of the protein. The change in the capping agent from citrate to borohydride weakened the binding of nanoparticles with the protein. But the same change in capping agent had increased the fluorescence quenching efficiency of AgNPs. Hydrogen bonding and van der Waals interactions were involved in BGG–BAgNPs complex similar to the CAgNPs complex with γ-globulin. Polarity of the Trp microenvironment in BGG was not altered using BAgNPs as opposed to CAgNPs, as supported using synchronous and three-dimensional fluorescence. Resonance light scattering experiments also suggested nano-bio conjugation. Far-UV and near-UV circular dichroism (CD) spectra respectively pointed towards changes in the secondary and tertiary structure of BGG by BAgNPs, which was not observed for CAgNPs.     

CpG-ODN Class C Mediated Immunostimulation in Rabbit Model of Trypanosoma evansi Infection

CpG oligodeoxynucleotides (CpG-ODN) stimulate immune cells from a wide spectrum of mammalian species. Class C CpG-ODN is relatively stable and has the combined immune effects of both A and B classes of CpG-ODN. Trypanosoma evansi produces the state of immuno-suppression in the infected hosts. The current chemotherapeutic agents against this parasite are limited in number and usually associated with severe side effects. The present work aimed to determine the immunostimulatory effects of CpG-ODN class C in T. evansi infected rabbits. Rabbits inoculated with CpG C and challenged with T. evansi resulted in delayed onset of clinical signs with reduced severity in comparison to that of T. evansi infected rabbits. The treatment also enhanced humoral immune responses. Histopathological findings in liver and spleen revealed enhancement of mononuclear cell infiltration and secondary B cell follicles. These results demonstrate that CpG-ODN class C, has immunostimulatory properties in rabbit model of trypanosomosis. The use of booster doses or sustained delivery of CpG-ODN will further elucidate the prolonged CpG-ODN generated immune responses.