A Review on Traditional Ecological Knowledge and Its Role in Natural Resources Management: North East India, a Cultural Paradise.

Sustainable management of natural resources plays a critical role in poverty alleviation and overall socio-economic development. North East (NE) India is blessed as a biodiversity hotspot, being also home to around 150 ethnic tribes with diverse ethical, cultural and traditional beliefs, endorsing the region as a cultural paradise rich in natural resources and traditional ecological knowledge (TEK). Conversely, the severely constrained nature of TEK, has juxtaposed TEK practices and sustainable natural resources management (NRM) in this review. Deliberating on the broader perspectives of TEK and ensuing practices, we have identified twelve sustainable development goals (SDGs) which are directly correlated to the TEK and practices of NE region. This review has meticulously detailed TEK and practices that can help in achieving various sustainable development targets of different SDGs in a more comprehensive and eco-friendly manner. Houde's manifestation to differentiate each element of TEK and practices present in the NE region of the country, such as traditional farming and irrigation systems, sacred groves, and cultural belief systems of different tribes, have been systematically analyzed and documented for each of the eight states of this region. The benefits accrued modern practices related to NRM are correlated with TEK, or adaptive empirical knowledge system. Indigenous agricultural systems, watershed management, biodiversity conservation, and ethnomedicinal therapeutic systems in NE India formed a vital part of the review. However, rapid urbanization, industrialization, and deforestation warrant an urgent need to systematically collate, document, analyze, and conserve the TEK of the indigenous communities of NE India.

Anti-quorum sensing and anti-biofilm activity of 5-hydroxymethylfurfural against Pseudomonas aeruginosa PAO1: Insights from in vitro, in vivo and in silico studies.

Pseudomonas aeruginosa is one of the most common pathogens associated with nosocomial infections and a great concern to immunocompromised individuals especially in the cases of cystic fibrosis, AIDS and burn wounds. The pathogenicity of P. aeruginosa is largely directed by the quorum sensing (QS) system. Hence, QS may be considered an important therapeutic target to combat P. aeruginosa infections. The anti-quorum sensing and anti-biofilm efficacy of aromatic aldehyde, 5-hydroxymethylfurfural (5-HMF) against P. aeruginosa PAO1 were assessed. At the sub-inhibitory concentration, 5-HMF suppressed the production of QS-controlled virulence phenotypes and biofilm formation in P. aeruginosa. It was also able to significantly enhance the survival rate of C. elegans infected with P. aeruginosa. The in silico studies revealed that 5-HMF could serve as a competitive inhibitor for the auto-inducer molecules as it exhibited a strong affinity for the regulatory proteins of the QS-circuits i.e. LasR and RhlR. In addition, a significant down-regulation in the expression of QS-related genes was observed suggesting the ability of 5-HMF in mitigating the pathogenicity of P. aeruginosa.

Green Synthesized Nanomaterials as Theranostic Platforms for Cancer Treatment: Principles, Challenges and the Road Ahead.

With the emergence of nanotechnology, new methods have been developed for engineering various nanoparticles for biomedical applications. Nanotheranostics is a burgeoning research field with tremendous prospects for the improvement of diagnosis and treatment of various cancers. However, the development of biocompatible and efficient drug/gene delivery theranostic systems still remains a challenge. Green synthetic approach of nanoparticles with low capital and operating expenses, reduced environmental pollution and better biocompatibility and stability is a latest and novel field, which is advantageous over chemical or physical nanoparticle synthesis methods. In this article, we summarize the recent research progresses related to green synthesized nanoparticles for cancer theranostic applications, and we also conclude with a look at the current challenges and insight into the future directions based on recent developments in these areas.

Evaluation of in vivo antioxidant potential of Syzygium jambos (L.) Alston and Terminalia citrina Roxb. towards oxidative stress response in Saccharomyces cerevisiae.

Excessive production and restricted elimination of free radicals like superoxide, hydroxyl radical (·OH), anion radical (O2 ·-), and non-radical hydrogen peroxide (H2O2) are related to the development of cancer, arteriosclerosis, arthritis and neurodegenerative diseases. According to a report of World Health Organisation, about 80% of the population living in the developing countries predominantly depends on the traditional medicine for their primary healthcare. Plants possess innate ability to synthesize a wide variety of enzymatic and non-enzymatic antioxidants capable of attenuating ROS-induced oxidative damage. The ethanolic leaf extracts of Syzygium jambos L. and Terminalia citrina Roxb. exhibited a significant in vitro antioxidant activity when compared with natural antioxidant, ascorbic acid. The extracts also provided strong cellular protection against the damaging effects of H2O2 induced oxidative stress in the mutant strains (tsa1Δ and sod1Δ) of Saccharomyces cerevisiae. The GC-MS analysis of the leaf extracts revealed the presence of phytoconstituents majorly constituting of terpenes, vitamin and fatty acids contributing to the antioxidant property. The plant extracts may serve as a potential source of exogenous antioxidants to combat the undesirable effects of oxidative stress.

Cinnamic acid attenuates quorum sensing associated virulence factors and biofilm formation in Pseudomonas aeruginosa PAO1.

OBJECTIVE: Anti-quorum sensing and anti-biofilm efficacy of Cinnamic acid against Pseudomonas aeruginosa was comparatively assessed with respect to potent quorum sensing inhibitor, Baicalein. RESULTS: At sub-lethal concentration, Cinnamic acid effectively inhibited both the production of the QS-dependent virulence factors and biofilm formation in P. aeruginosa without affecting the viability of the bacterium. The phytocompound interfered with the initial attachment of planktonic cells to the substratum thereby causing reduction in biofilm development. In addition, the in vivo study indicated that the test compound protected Caenorhabditis elegans from the virulence factors of P. aeruginosa leading to reduced mortality. The in silico analysis revealed that Cinnamic acid can act as a competitive inhibitor for the natural ligands towards the ligand binding domain of the transcriptional activators of the quorum sensing circuit in P. aeruginosa, LasR and RhlR. CONCLUSIONS: The findings suggest that Cinnamic acid may serve as a novel quorum sensing based anti-infective in controlling P. aeruginosa infections.

Attenuation of quorum sensing controlled virulence factors and biofilm formation in Pseudomonas aeruginosa by pentacyclic triterpenes, betulin and betulinic acid.

The production of virulence determinants and biofilm formation in numerous pathogens is regulated by the cell-density-dependent phenomenon, Quorum sensing (QS). The QS system in multidrug resistant opportunistic pathogen, P. aeruginosa constitutes of three main regulatory circuits namely Las, Rhl, and Pqs which are closely linked to its pathogenicity and establishment of chronic infections. In spite intensive antibiotic therapy, P. aeruginosa continue to be an important cause of nosocomial infections and also the major cause of mortality in Cystic Fibrosis patients with 80% of the adults suffering from chronic P. aeruginosa infection. Hence, targeting QS circuit offers an effective intervention to the ever increasing problem of drug resistant pathogens. In the present study, the pentacyclic triterpenes i.e. Betulin (BT) and Betulinic acid (BA) exhibited significant attenuation in production of QS-regulated virulence factors and biofilm formation in P. aeruginosa, at the sub-lethal concentration. The test compound remarkably interfered in initial stages of biofilm development by decreasing the exopolysaccharide production and cell surface hydrophobicity. Based on the in vivo studies, the test compounds notably enhanced the survival of Caenorhabditis elegans infected with P. aeruginosa. Furthermore, molecular docking analysis revealed that BT and BA can act as a strong competitive inhibitor for QS receptors, LasR and RhlR. The findings suggest that BT and BA can serve as potential anti-infectives in the controlling chronic infection of P. aeruginosa.

Green synthesis of anisotropic gold nanoparticles using hordenine and their antibiofilm efficacy against Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a notorious pathogen that causes biofilm aided infections in patients with cystic fibrosis and burn wounds, resulting in significant mortality in immunocompromised individuals. This study reports a novel one-step biosynthesis of gold nanoparticles using phytocompound, hordenine (HD), as a reducing and capping agent. The synthesis of the anisotropic hordenine-fabricated gold nanoparticles (HD-AuNPs) with an average particle size of 136.87 nm was achieved within 12 h of incubation at room temperature. Both HD and HD-AuNPs exhibited significant antibiofilm activity against P. aeruginosa PAO1, although greater biofilm inhibition was observed for the nanoparticles as compared to hordenine alone. In the microtitre plate assay and tube method, the nanoparticles significantly inhibited the biofilm formation by 73.69 and 78.41%, respectively. The exopolysaccharide production by the test pathogen was arrested by 68.46% on treatment with the nanoparticles. Further, the effect of HD and HD-AuNPs on the biofilm architecture of P. aeruginosa was revealed by light and confocal laser-scanning microscopy micrographs. The overall results of this study suggested the synergistic antibiofilm effect of AuNPs and HD for the treatment of chronic bacterial infections caused by biofilms forming pathogens.

Facile green synthesis of baicalein fabricated gold nanoparticles and their antibiofilm activity against Pseudomonas aeruginosa PAO1.

Biofilm formation is one of the major problems associated with chronic diseases and also attributes for the antibiotic resistance in bacteria. In recent times nanoparticles have been utilized to improve the efficacy of the existing antimicrobial and anti-biofilm agents. The ease in functionalization of gold nanoparticles (AuNPs) makes them a potential carrier for antimicrobial agents. However, the use of physical or chemical methods of the production of nanoparticles is expensive, labour intensive and hazardous to ecosystem. On the other hand, the use of plant based compounds serve as an eco-friendly way for the synthesis of nanoparticles with improved biocompatibility and therapeutic applicability. In the present study, phytocompound, baicalein was used as a reducing and capping agent for the synthesis of spherical shape AuNPs. The baicalein decorated gold nanoparticles (BCL-AuNPs) were characterized and evaluated for their anti-biofilm efficacy against Pseudomonas aeruginosa PAO1. The biosynthesized BCL-AuNPs was characterized using UV-Visible spectra, Dynamic Light Scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Diffraction (EDAX), and High Resolution Transmission Electron Microscopy (HR-TEM). The biosynthesized BCL-AuNPs were determined to be spherical in shape with an average size of 26.5 nm. The sub-MIC concentration of BCL-AuNPs exhibited significant anti-biofilm activity against P. aeruginosa PAO1. On treatment with BCL-AuNPs (100 g mL-1), a reduction in biofilm formation by 58.74 ± 5.8% and 76.51 ± 4.27% was observed in microtiter plate assay and tube method, respectively. A significant reduction in exopolysaccharide (EPS) production by 81.29± 2.96% was observed. The swimming and swarming motility were also effectively arrested in presence of BCL-AuNPs. Further, Light microscope and CLSM studies were carried out to examine the effect of BCL-AuNPs on the surface topography and architecture of P. aeruginosa biofilm. Thus, the present study suggests the potential use of BCL-AuNPs in the development of novel therapeutics for the prevention and treatment of biofilm associated chronic infections.

Ecofriendly biosorption of dyes and metals by bacterial biomass of Aeromonas hydrophila RC1.

The ability of dried bacterial biomass in azo dye and heavy metal removal from aqueous solution was explored. Biosorption of three textile dyes, Eriochrome black T (EBT), Acid Red 26 (AR) and Trypan blue (TB) and heavy metals (Pb and Cr) by dried biomass of Aeromonas hydrophila RC1, was investigated in a batch system under various parameters such as dye concentration, contact time, concentration of biomass, pH, and temperature. The experimental results showed that the extent of biosorption for dyes increased with increase in initial concentration of dyes, biomass concentration, contact time, temperature and decreased with increase in pH. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm equations. The Langmuir model yielded good fit to the experimental data (R² approximately 0.794, 0.844 and 0.969 for the dyes, EBT, AR and TB, respectively) with maximum monolayer adsorption capacity of 58.8 mg g⁻¹ for AR. Similarly results were obtained for heavy metals and the data fit in Langmuir model (R² value of 0.849 and 0.787) with q(m) value of 40 mg g⁻¹ for Pb. The results fit in pseudo first order kinetics with removal upto 96.67 % for Pb. Involvement of the surface characteristics of the biomass in biosorption was studied using scanning electron micrographs, FTIR, EDX and XRD analysis. Thus, use ofA. hydrophila RC1 biomass can be extensively employed in water treatment plants in order to get desired water quality in the most economical way.

Green rapid biogenic synthesis of bioactive silver nanoparticles (AgNPs) using Pseudomonas aeruginosa.

The present work was focused on isolating a bacterial strain of Pseudomonas sp. with the ability to synthesise AgNPs rapidly. A strain of Pseudomonas aeruginosa designated JO was found to be a potential candidate for rapid synthesis of AgNPs with a synthesis time of 4h in light, at room temperature which is a shorter time period noticed for the synthesis when compared to the previous reports Biosynthesis of AgNPs was achieved by addition of culture supernatant with aqueous silver nitrate solution (1 mM). The reaction mixture exhibits change in colour from green to brown with a peak at 420 nm corresponding to the plasmon absorbance of AgNPs by UV-vis spectroscopy. The nanoparticles were characterised by X-ray diffraction (XRD), energy-dispersive X-ray analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), Zetasizer and transmission electron microscopy (TEM). The XRD spectrum exhibited 2θ values corresponding to the silver nanocrystals. TEM and SEM micrographs revealed the extracellular formation of polydispersed elongated nanoparticles with an average size of 27.5 nm. Synthesised nanoparticles showed antibacterial property against both gram-positive and gram-negative microorganisms, but more effective towards gram-negative.