Attenuation of quorum sensing regulated virulence functions and biofilm of pathogenic bacteria by medicinal plant Artemisia annua and its phytoconstituent 1, 8-cineole.

The emergence of multidrug resistance (MDR) in bacterial pathogens is a serious public health concern. A significant therapeutic target for MDR infections is the quorum sensing-regulated bacterial pathogenicity. Determining the anti-quorum sensing abilities of certain medicinal plants against bacterial pathogens as well as the in-silico interactions of particular bioactive phytocompounds with QS and biofilm-associated proteins were the objectives of the present study. In this study, 6 medicinal plants were selected based on their ethnopharmacological usage, screened for Anti-QS activity and Artemisia annua leaf extract (AALE) demonstrated pigment inhibitory activity against Chromobacterium violaceum CV12472. Further, the methanol active fraction significantly inhibited the virulence factors (pyocyanin, pyoverdine, rhamnolipid and swarming motility) of Pseudomonas aeruginosa PAO1 and Serratia marcescens MTCC 97 at respective sub-MICs. The inhibition of biofilm was determined using a microtiter plate test and scanning electron microscopy. Biofilm formation was impaired by 70%, 72% and 74% in P. aeruginosa, C. violaceum and S. marcescens, respectively at 0.5xMIC of the extract. The phytochemical content of the extract was studied using GC-MS and 1, 8-cineole was identified as major bioactive compound. Furthermore, 1, 8-cineole was docked with quorum sensing (QS) proteins (LasI, LasR, CviR, and rhlR) and biofilm proteins (PilY1 and PilT). In silico docking and dynamics simulations studies suggested interactions with QS-receptors CviR', LasI, LasR, and biofilm proteins PilY1, PilT for anti-QS activity. Further, 1, 8-cineole demonstrated 66% and 51% reduction in violacein production and biofilm formation, respectively to validate the findings of computational analysis. Findings of the present investigation suggests that 1, 8-cineole plays a crucial role in the QS and biofilm inhibitory activity demonstrated by Artemisia annua extract. RESEARCH HIGHLIGHTS: Artemisia annua leaf extract (AALE) methanol fraction demonstrated broad-spectrum QS and biofilm inhibition Scanning electron microscopy (SEM) confirmed biofilm inhibition Molecular docking and simulation studies suggested positive interactions of 1,8-cineol with QS-receptors and biofilm proteins.

Antibiofilm and anti-quorum sensing activity of Psidium guajava L. leaf extract: In vitro and in silico approach.

The quorum sensing mechanism relies on the detection and response to chemical signals, termed autoinducers, which regulate the synthesis of virulence factors including toxins, enzymes, and biofilms. Emerging therapeutic strategies for infection control encompass approaches that attenuate quorum-sensing systems. In this study, we evaluated the antibacterial, anti-quorum sensing, and anti-biofilm activities of Psidium guajava L. methanolic leaf extracts (PGME). Minimum Inhibitory Concentrations (MICs) of PGME were determined as 500 µg/ml for C. violaceum and 1000 µg/ml for P. aeruginosa PAO1. Significantly, even at sub-MIC concentrations, PGME exhibited noteworthy anti-quorum sensing properties, as evidenced by concentration-dependent inhibition of pigment production in C. violaceum 12742. Furthermore, PGME effectively suppressed quorum-sensing controlled virulence factors in P. aeruginosa PAO1, including biofilm formation, pyoverdin, pyocyanin, and rhamnolipid production, with concentration-dependent inhibitory effects. Phytochemical analysis utilizing GC-MS revealed the presence of compounds such as alpha-copaene, caryophyllene, and nerolidol. In-silico docking studies indicated a plausible mechanism for the observed anti-quorum sensing activity, involving favorable binding and interactions with QS-receptors, including RhlR, CviR', LasI, and LasR proteins. These interactions were found to potentially disrupt QS pathways through suppression of AHL production and receptor protein blockade. Collectively, our findings propose PGME as a promising candidate for the treatment of bacterial infections. Its attributes that mitigate biofilm development and impede quorum-sensing mechanisms highlight its potential therapeutic value.

Biotechnological Intervention and Secondary Metabolite Production in Centella asiatica L.

Centella asiatica L., commonly known as Gotu kola, Indian pennywort, and Asiatic pennyworts, is an herbaceous perennial plant that belongs to the family Apiaceae and has long been used in the traditional medicine system. The plant is known to produce a wide range of active metabolites such as triterpenoids including asiatic acid, asiaticoside, brahmoside, and madecassic acid along with other constituents including centellose, centelloside, and madecassoside, etc., which show immense pharmacological activity. Due to its beneficial role in neuroprotection activity, the plant has been considered as a brain tonic. However, limited cultivation, poor seed viability with low germination rate, and overexploitation for decades have led to severe depletion and threatened its wild stocks. The present review aimed to provide up-to-date information on biotechnological tools applied to this endangered medicinal plant for its in vitro propagation, direct or indirect regeneration, synthetic seed production, strategies for secondary metabolite productions including different elicitors. In addition, a proposed mechanism for the biosynthesis of triterpenoids is also discussed.

Micropropagation, encapsulation, physiological, and genetic homogeneity assessment in Casuarina equisetifolia.

Casuarina equisetifolia is an important tree of the forest, cultivated in tropical and subtropical regions, providing fuelwood, land reclamation, dune stabilization, paper production, and nitrogen fixation. We have developed a systematic in vitro propagation protocol in C. equisetifolia using nodal segments (NS). Murashige and Skoog (MS) medium augmented with BA (5.0 µM) and NAA (0.5 µM) gave rise to a maximum of 32.00 ± 0.31 shoots per explant (S/E) with shoot length (SL) of 3.94 ± 0.02 cm, and a maximum of 70% regeneration potential (RP) was recorded after 8 weeks of post inoculation. For root induction, in vitro derived shoots were transferred to the nutrient medium consisting of a half-strength (½) MS medium augmented with 2.5 µM NAA, which produced a maximum of 12.68 ± 0.33 roots/shoot (R/S) with 3.04 ± 0.50 cm root length (RL) in 60% of culture after 6 weeks. Micropropagated plants with healthy shoots and roots were successfully acclimatized in vermicompost + garden soil + sand (1:2:1) and a maximum survival percentage of 95.1% was recorded. NS was taken from a 6-weeks-old in vitro derived plant of C. equisetifolia for synthetic seed production, and it was reported that CaCl2 · 2H2O (100 mM) + Na2-alginate (4%) resulted in clear and uniform beads. Furthermore, the maximum conversion of synthetic seeds into plantlets occurred over a period of 4 weeks of storage at 4°C. Scanning Electron Microscopy (SEM) revealed the formation of direct shoot buds without any intermediate callus formation. In addition, the chlorophyll and carotenoid contents of the direct regenerated and mother plant were compared. Similarly, RAPD and ISSR primers were used for genetic homogeneity assessment of the direct regenerated plants, where a total of 18 and 19, respectively, clear and reproducible bands with 100% monomorphism were recorded. The developed micropropagation protocol can certainly be used for large-scale multiplication and germplasm preservation of C. equisetifolia. It will also help in meeting the growing demands of C. equisetifolia in the forest industry.

Anti-quorum sensing, antibiofilm, and antibacterial activities of extracts of Centella asiatica L. leaves, and in vitro derived leaves-calli through tissue culture: a potential for biofouling-prevention.

Extracts of Centella asiatica leaves (LEs), and in-vitro leaf-calli (CEs), were investigated for antibacterial, antibiofilm, and anti-quorum sensing activities. Ethyl acetate extracts from leaves (EALE), leaf-calli (EACE), methanolic extracts from leaves (MELE), and leaf-calli (MECE) showed antibacterial activity; the minimum inhibitory concentrations (MICs) of LEs and CEs ranged from 0.312-2.50 mg ml-1 and 0.625 - 2.50 mg ml-1, respectively. The MICs of EALE and EACE were 2.50 mg ml-1, each, for C. violaceum 12742, and P. aeruginosa PAO1. At sub-MIC levels, EALE and EACE showed anti-quorum sensing (anti-QS) activity, demonstrated by concentration dependent pigment inhibition of C. violaceum 12742. Similarly, EALE and EACE inhibited QS-controlled virulence factors in P. aeruginosa PAO1 (biofilm, pyocyanin, and pyoverdin); again, the inhibition was concentration-dependent. The best effect was at immediate sub-MIC concentration i.e. 1250 µg ml-1. GC-MS analyses revealed the presence of compound 9,12-Octadecadienoic acid, and in silico docking study suggested interactions with QS-receptors CviR', LasI, and LasR proteins for anti-QS activity.

Nanotechnological Interventions in Agriculture.

Agriculture is an important sector that plays an important role in providing food to both humans and animals. In addition, this sector plays an important role in the world economy. Changes in climatic conditions and biotic and abiotic stresses cause significant damage to agricultural production around the world. Therefore, the development of sustainable agricultural techniques is becoming increasingly important keeping in view the growing population and its demands. Nanotechnology provides important tools to different industrial sectors, and nowadays, the use of nanotechnology is focused on achieving a sustainable agricultural system. Great attention has been given to the development and optimization of nanomaterials and their application in the agriculture sector to improve plant growth and development, plant health and protection and overall performance in terms of morphological and physiological activities. The present communication provides up-to-date information on nanotechnological interventions in the agriculture sector. The present review deals with nanoparticles, their types and the role of nanotechnology in plant growth, development, pathogen detection and crop protection, its role in the delivery of genetic material, plant growth regulators and agrochemicals and its role in genetic engineering. Moreover, the role of nanotechnology in stress management is also discussed. Our aim in this review is to aid researchers to learn quickly how to use plant nanotechnology for improving agricultural production.

Effect of adenine sulphate interaction on growth and development of shoot regeneration and inhibition of shoot tip necrosis under in vitro condition in adult Syzygium cumini L.--a multipurpose tree.

An efficient method for cloning Syzygium cumini (above 40 years old) through mature nodal segments has been successfully developed and that could be exploited for large-scale production of this valuable multipurpose tree. Nodal segments from mature tree were taken as explants and cultured on MS basal medium with different cytokinins (BA, Kin, AdS). The application of BA proved to be the best responsive cytokinin for the induction of shoot buds and shoots, but the proliferated shoots exhibited slower and stunted growth accompanied with abscission of leaves and shoot tip necrosis (STN). The problem of leaf abscission and STN was considerably reduced by the application of an adjuvant, adenine sulphate (AdS) in the optimal medium which led to the production of a maximum of 14 shoots. Further improvement in shoot bud regeneration and improved growth pattern of the regenerating tissue was obtained on the media comprised of MS + BA (10 µM) + GA3 (2.5 µM). A total number of 15 shoots with mean shoot length of 5.9 cm was obtained. The healthy elongated shoots were then rooted on MS basal augmented with NAA (5 µM). The plantlets obtained were healthy and were successfully acclimatized and transferred under field condition with 70 % survival rate.

Synseed technology-a complete synthesis.

Progress in biotechnological research over the last two decades has provided greater scope for the improvement of crops, forest trees and other important plant species. Plant propagation using synthetic seeds has opened new vistas in the field of agriculture. Synseed technology is a highly promising tool for the management of transgenic and seedless plant species, polyploid plants with elite traits and plant lines that are difficult to propagate through conventional propagation methods. Delivery of synseeds also alleviates issues like undertaking several passages for scaling up in vitro cultures as well as acclimatization to ex vitro conditions. Optimization of synchronized propagule development followed by automation of the whole process (sorting, harvesting, encapsulation and conversion) can enhance the pace of synseed production. Cryopreservation of encapsulated germplasm has now been increasingly used as an ex vitro conservation tool with the possible minimization of adverse effects of cryoprotectants and post-preservation damages. Through synseed technology, germplasm exchange between countries could be accelerated as a result of reduced plant quarantine requirements because of the aseptic condition of the plant material.

Thrombus volume is associated with cardiovascular events and aneurysm growth in patients who have abdominal aortic aneurysms.

BACKGROUND: Patients with abdominal aortic aneurysms (AAA) are predisposed to cardiovascular events and often experience continual expansion of their aneurysm. Cardiovascular events and expansion rates are positively correlated with aneurysm size. AAA is usually associated with intraluminal thrombus, which has previously been implicated in AAA pathogenesis. This study prospectively assessed the association of infrarenal abdominal aortic thrombus volume with cardiovascular events and AAA growth. METHODS: Ninety-eight patients with AAAs underwent computed tomography angiography (CTA). The volume of infrarenal aorta thrombus was measured by a previously validated technique. Patients were monitored prospectively for a median of 3 years (interquartile range [IQR], 2.0-3.6 years), and cardiovascular events (nonfatal stroke, nonfatal myocardial infarction, coronary revascularization, amputation, and cardiovascular death) were recorded. Of the original patients, 39 underwent repeat CTA a median of 1.5 years (IQR, 1.1-3.3 years) after entry to the study. Kaplan-Meier and Cox proportional analysis were used to examine the association of aortic thrombus with cardiovascular events and average weighted AAA growth. RESULTS: There were 28 cardiovascular events during follow-up. The incidence of cardiovascular events was 23.4% and 49.2% for patients with small (smaller than the median) and large (median or larger) volumes of aortic thrombus, respectively, at 4 years (P = .040). AAA thrombus volume of median or larger was associated with increased cardiovascular events (relative risk [RR] 2.8, 95% confidence interval [CI], 1.01-5.24) independent of other risk factors, including initial AAA diameter, but was only of borderline significance when patients were censored at the time of AAA repair (RR, 2.35; 95% CI, 0.98-5.63). In the subset of patients with CTA follow-up, the median annual increase in AAA volume was 5.1 cm³ (IQR, 0.8-10.3 cm³). Annual AAA volume increase was positively correlated with initial AAA diameter (r = 0.44, P = .006) and thrombus volume (r = 0.50, P = .001). Median or larger aortic thrombus volume was associated with rapid AAA volume increase (≥ 5 cm/y), independent of initial aortic diameter (RR, 15.0; 95% CI, 1.9-115.7; P = .009). CONCLUSION: In this small cohort, infrarenal aortic thrombus volume was associated with the incidence of cardiovascular events and AAA progression. These results need to be confirmed and mechanisms underlying the associations clarified in large further studies.

Relation of infra-renal abdominal aortic calcific deposits and cardiovascular events in patients with peripheral artery disease.

In patients with peripheral artery disease, aortic calcific deposits are a common finding. The aim of this study was to assess the association of infrarenal abdominal aortic calcific deposits with prospective cardiovascular events in patients with peripheral artery disease. A consecutive series of 213 patients who presented for investigation of abdominal aortic aneurysm or intermittent claudication were assessed using computed tomographic angiography. Infrarenal abdominal aortic calcific deposits were estimated using a previously defined highly reproducible semiautomated program. Patients were followed prospectively for a median of 2.8 years (interquartile range 1.7 to 3.6), and cardiovascular events were recorded. Kaplan-Meier and Cox proportional-hazards analysis were used to examine the association of calcific deposits with cardiovascular events. A total of 45 cardiovascular events occurred during follow-up, including nonfatal myocardial infarction (n = 23), coronary revascularization (n = 6), stroke (n = 3), below-knee amputation (n = 2), and cardiovascular death (n = 11). The incidence of cardiovascular events was 21.7%, 33.0%, and 36.9% for patients with mild (<400 mm(3)), intermediate (400 to 1,700 mm(3)), and severe (>1,700 mm(3)) abdominal aortic calcific deposits, respectively (p = 0.039). Calcific deposit volume >400 mm(3) (relative risk 2.8, 95% confidence interval 1.2 to 6.6) and coronary artery disease (relative risk 2.8, 95% confidence interval 1.4 to 5.6) were independently associated with increased cardiovascular events during follow-up. In conclusion, abdominal aortic calcific deposits are prognostic for cardiovascular events in patients with peripheral artery disease.

TDZ-induced high frequency shoot regeneration in Cassia sophera Linn. via cotyledonary node explants.

Cassia sophera Linn. is an important medicinal plant belonging to family Fabaceae. It is extensively used in Homeopathy and is well known for its medicinal properties. The present study describes a simple, efficient and reproducible regeneration system for in vitro propagation of C. sophera through cotyledonary node (CN) explant excised from 21 d old axenic seedlings. Explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of thidiazuron (TDZ). Multiple shoots were produced on all the concentrations of TDZ; however 2.5 µM concentration proved to be optimal for the production of maximum number of shoots. To avoid adverse effects of prolonged exposure to TDZ in long term establishment, the cultures were transferred to TDZ free MS medium fortified with various concentrations of 6- benzyl aminopurine (BA) for multiplication, proliferation and elongation of induced shoots. Emergence of new shoot buds and multiplication continued up to second subculture passage and maximum number (14.9 ± 1.4) of shoots obtained on MS + BA (1.0 µM). Best rooting response was observed on half strength MS containing Indole-3-butyric acid (IBA) (1.0 µM). Regenerated plantlets were successfully acclimatized and hardened off inside the culture room and then transferred to green house with 100 % survival rate.

Antibacterial activity of aerial parts as well as in vitro raised calli of the medicinal plant Saraca asoca (Roxb.) de Wilde.

Leaves, stem, and flowers of Saraca asoca, an endangered medicinal plant in India, and young explants cultivated on Murashige & Skoog's medium containing 6-benzylaminopurine were analyzed for antibacterial potential. Alcoholic and aqueous extracts from parent explants and their in vitro raised calli were tested by an agar well diffusion method. Minimal inhibitory concentrations (MICs) of the extracts were determined by broth microdilution method. Aqueous extracts showed antibacterial activity against limited bacterial species, whereas alcoholic extracts were active against a wider range of bacteria. Although the alcoholic extracts of all the explants and calli showed antibacterial activity, the extracts derived from flowers and their calli showed better results. Extracts derived from calli showed comparable results to the extracts from explants. Overall, the MICs of the extracts ranged from 0.039 to 1.25 mg/mL. MICs against gram-positive bacteria ranged from 0.078 to 1.25 mg/mL, whereas they ranged between 0.039 and 0.625 mg/mL against gram-negative bacteria. A MIC distribution plot showed that gram-negative bacteria were more susceptible to the extracts than gram-positive bacteria. It is concluded that extracts of S. asoca contain antibacterial agent, and as the calli gave good results, in vitro cultivation of the explants may be used to obtain antibacterial compounds. This is the first report on antibacterial activity of S. asoca, especially through in vitro raised calli.