Chemotactic responses of sweet flag (Acorus calamus L.) root exudates and evaluation of inoculation effects on its growth

Saabunud / Received 04.11.2020 ; Aktsepteeritud / Accepted 20.04.2021 ; Avaldatud veebis / Published online 20.04.2021 ; Vastutav autor / Corresponding author: B. Karthikeyan [email protected] exudate is an important source of nutrients for microorganisms in the rhizosphere and it plays a major role in the early colonization including chemotactic responses and adsorption of rhizospheric bacteria. In this study, we characterized the root exudates from sweet flag under hydroponic conditions and assessed their effect on plant growth. In the present study, the crude root fractions of sweet flag recorded a maximum yield of 520.6 μg plant–1 followed by cationic, anionic and neutral fractions. Among the qualitative and quantitative analysis of different fractions, the cationic fraction recorded a maximum of 90 μg plant–1 for glutamic acid, followed by aspartic acid, glycine, serine and proline. In the anionic fraction, malic acid recorded a maximum of 78.0 μg plant–1 followed by oxalic, succinic, citric and glutamic acid fractions. The neutral fractions included different saccharides, among which, fructose recorded a maximum of 42.5 μg plant–1, followed by glucose, maltose, ribose and arabinose. The relative chemotactic response (RCR) of PGPB (plant growth-promoting bacteria) strains towards different root exudate fractions of Acorus calamus was recorded and it was observed that the combination of Anionic + Cationic + Neutral fraction recorded maximum chemotactic response for PGPR strains. The adsorption of PGPR strains in the root of the Acorus calamus was recorded in three different phases of growth and among these, Log phase bacterial cells exhibited maximum colonization of 7.65 × 10–6 cells g–1 with A.venilandii (ACAzt-2). Inoculation effect of PGPB strains on the root exudate of Acorus calamus and its growth was evaluated and it was observed that the treatment T5 – Consortium recorded maximum plant height and root growth of Acorus calamus, followed by T2. Our results indicate that sweet flag root exudates induce chemotactic responses of PGPR strains and promoted their growth

MECHANICAL PROPERTIES OF SISAL/GLASS FIBER REINFORCED HYBRID COMPOSITES: A REVIEW

The natural fiber-reinforced polymer composite is swiftly growing both in phrases of their industrial applications and fundamental research. They are renewable, cheap, absolutely or in part recyclable and biodegradable. The incorporation of herbal fibers consisting of sisal with glass fiber hybrid composites has additionally received growing industrial packages. Herbal and synthetic fibers are mixed in the same matrix (unsaturated polyester) to make sisal/glass fiber hybrid composites and the mechanical residences of those hybrid composites had been studied. A giant development in mechanical homes of sisal/glass fiber hybrid composites has been observed. the chalk powder (additive) is likewise introduced to the resin (unsaturated polyester) in proportions of 1%, 2%, 3% by way of weight of resin respectively and sisal/glass fiber hybrid composites were organized through the usage of this resin to take a look at the effect of chalk powder on mechanical homes of those hybrid composites. It is also found that because the chalk powder quantity increases tensile and flexural residences are decreases

PI-tuned UPFC damping controllers design for multi-machine power system

This paper presents an adaptive multi-objective algorithm based Unified Power Flow Controller (UPFC) tuned for damping oscillations in two-area multi-machine system formulated as multi- objective optimization problem. The algorithms such as, Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Modified Non-dominated Sorting Genetic Algorithm-II (MNSGA-II) are proposed for tuning the damping controller with speed deviation and control input as conflicting objectives. The proposed algorithm is implemented in the two area multi-machine system using MATLAB Simulink model, and the simulation results were obtained with respect to the characteristics of damping oscillations and the dynamic stability of power systems. The performance measures such as Integral Time Squared Error (ITSE) and Integral Squared Error (ISE) are considered as the objective functions. The results of the two proposed algorithm has been compared and the outcome shows that the MNSGA-II algorithm performs better compared to the NSGA-II algorithm

Stabilizing contributions of sulfur-modified nucleotides: crystal structure of a DNA duplex with 2′-O-[2-(methoxy)ethyl]-2-thiothymidines

Substitution of oxygen atoms by sulfur at various locations in the nucleic acid framework has led to analogs such as the DNA phosphorothioates and 4′-thio RNA. The phosphorothioates are excellent mimics of DNA, exhibit increased resistance to nuclease degradation compared with the natural counterpart, and have been widely used as first-generation antisense nucleic acid analogs for applications in vitro and in vivo. The 4′-thio RNA analog exhibits significantly enhanced RNA affinity compared with RNA, and shows potential for incorporation into siRNAs. 2-Thiouridine (s(2)U) and 5-methyl-2-thiouridine (m(5)s(2)U) are natural nucleotide analogs. s(2)U in tRNA confers greater specificity of codon–anticodon interactions by discriminating more strongly between A and G compared with U. 2-Thio modification preorganizes the ribose and 2′-deoxyribose sugars for a C3′-endo conformation, and stabilizes heteroduplexes composed of modified DNA and complementary RNA. Combination of the 2-thio and sugar 2′-O-modifications has been demonstrated to boost both thermodynamic stability and nuclease resistance. Using the 2′-O-[2-(methoxy)ethyl]-2-thiothymidine (m(5)s(2)Umoe) analog, we have investigated the consequences of the replacement of the 2-oxygen by sulfur for base-pair geometry and duplex conformation. The crystal structure of the A-form DNA duplex with sequence GCGTAT*ACGC (T* = m(5)s(2)Umoe) was determined at high resolution and compared with the structure of the corresponding duplex with T* = m(5)Umoe. Notable changes as a result of the incorporation of sulfur concern the base-pair parameter ‘opening’, an improvement of stacking in the vicinity of modified nucleotides as measured by base overlap, and a van der Waals interaction between sulfur atoms from adjacent m(5)s(2)Umoe residues in the minor groove. The structural data indicate only minor adjustments in the water structure as a result of the presence of sulfur. The observed small structural perturbations combined with the favorable consequences for pairing stability and nuclease resistance (when combined with 2′-O-modification) render 2-thiouracil-modified RNA a promising candidate for applications in RNAi

Tailoring biomaterial surface properties to modulate host-implant interactions: implication in cardiovascular and bone therapy

Host body response to a foreign medical device plays a critical role in defining its fate post implantation. It is thus important to control host-material interactions by designing innovative implant surfaces. In the recent years, biochemical and topographical features have been explored as main target to produce this new type of bioinert or bioresponsive implants. The review discusses specific biofunctional materials and strategies to achieve a precise control over implant surface properties and presents possible solutions to develop next generation of implants, particularly in the fields of bone and cardiovascular therapy

Timing Offset Calibration of CZTI instrument aboard ASTROSAT

The radio as well as the high energy emission mechanism in pulsars is yet not understood properly. A multi-wavelength study is likely to help in better understanding of such processes. The first Indian space-based observatory, ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum from infra-red (1300 $\AA$) to hard X-ray (380 KeV). Cadmium Zinc Telluride Imager (CZTI), one of the five instruments is a hard X-ray telescope functional over an energy range of 20-380 KeV. We aim to estimate the timing offset introduced in the data acquisition pipeline of the instrument, which will help in time alignment of high energy time series with those from two other ground-based observatories, viz. the Giant Meterwave Radio Telescope (GMRT) and the Ooty Radio Telescope (ORT). PSR B0531+21 is a well-studied pulsar with nearly aligned radio and hard X-ray pulse profiles. We use simultaneous observations of this pulsar with the ASTROSAT, the ORT and the GMRT. The pulsar was especially observed using the ORT with almost daily cadence to obtain good timing solutions. We also supplement the ORT data with archival FERMI data for estimation of timing noise. The timing offset of ASTROSAT instruments was estimated from fits to arrival time data at the ASTROSAT and the radio observatories. We estimate the offset between the GMRT and the ASTROSAT-CZTI to be -4716 $\pm$ 50 $\mu s$. The corresponding offset with the ORT was -29639 $\pm$ 50 $\mu s$. The offsets between the GMRT and Fermi-LAT -5368 $\pm$ 56 $\mu s$. (Abridged)Comment: 6 pages, 5 figures, 2 tables, Revised and Updated, accepted for publication in A&

Feasibility of a multiparametric MRI protocol for imaging biomarkers associated with neoadjuvant radiotherapy for soft tissue sarcoma

OBJECTIVE: Soft tissue sarcoma (STS) is a rare malignancy with a 5 year overall survival rate of 55%. Neoadjuvant radiotherapy is commonly used in preparation for surgery, but methods to assess early response are lacking despite pathological response at surgery being predictive of overall survival, local recurrence and distant metastasis. Multiparametric MR imaging (mpMRI) is used to assess response in a variety of tumours but lacks a robust, standardised method. The overall aim of this study was to develop a feasible imaging protocol to identify imaging biomarkers for further investigation. METHODS: 15 patients with biopsy-confirmed STS suitable for pre-operative radiotherapy and radical surgery were imaged throughout treatment. The mpMRI protocol included anatomical, diffusion-weighted and dynamic contrast-enhanced imaging, giving estimates of apparent diffusion coefficient (ADC) and the area under the enhancement curve at 60 s (iAUC(60)). Histological analysis of resected tumours included detection of CD31, Ki67, hypoxia inducible factor and calculation of a hypoxia score. RESULTS: There was a significant reduction in T1 at visit 2 and in ADC at visit 3. Significant associations were found between hypoxia and pre-treatment iAUC(60), pre-treatment ADC and mid-treatment iAUC(60). There was also statistically significant association between mid-treatment ADC and Ki67. CONCLUSION: This work showed that mpMRI throughout treatment is feasible in patients with STS having neoadjuvant radiotherapy. The relationships between imaging parameters, tissue biomarkers and clinical outcomes warrant further investigation. ADVANCES IN KNOWLEDGE: mpMRI-based biomarkers have good correlation with STS tumour biology and are potentially of use for evaluation of radiotherapy response

Competition for RISC binding predicts in vitro potency of siRNA

Short interfering RNAs (siRNA) guide degradation of target RNA by the RNA-induced silencing complex (RISC). The use of siRNA in animals is limited partially due to the short half-life of siRNAs in tissues. Chemically modified siRNAs are necessary that maintain mRNA degradation activity, but are more stable to nucleases. In this study, we utilized alternating 2′-O-methyl and 2′-deoxy-2′-fluoro (OMe/F) chemically modified siRNA targeting PTEN and Eg5. OMe/F-modified siRNA consistently reduced mRNA and protein levels with equal or greater potency and efficacy than unmodified siRNA. We showed that modified siRNAs use the RISC mechanism and lead to cleavage of target mRNA at the same position as unmodified siRNA. We further demonstrated that siRNAs can compete with each other, where highly potent siRNAs can compete with less potent siRNAs, thus limiting the ability of siRNAs with lower potency to mediate mRNA degradation. In contrast, a siRNA with low potency cannot compete with a highly efficient siRNA. We established a correlation between siRNA potency and ability to compete with other siRNAs. Thus, siRNAs that are more potent inhibitors for mRNA destruction have the potential to out-compete less potent siRNAs indicating that the amount of a cellular component, perhaps RISC, limits siRNA activity

British Society of Gastroenterology guidelines for the diagnosis and management of cholangiocarcinoma

These guidelines for the diagnosis and management of cholangiocarcinoma (CCA) were commissioned by the British Society of Gastroenterology liver section. The guideline writing committee included a multidisciplinary team of experts from various specialties involved in the management of CCA, as well as patient/public representatives from AMMF (the Cholangiocarcinoma Charity) and PSC Support. Quality of evidence is presented using the Appraisal of Guidelines for Research and Evaluation (AGREE II) format. The recommendations arising are to be used as guidance rather than as a strict protocol-based reference, as the management of patients with CCA is often complex and always requires individual patient-centred considerations

Unexpected origins of the enhanced pairing affinity of 2′-fluoro-modified RNA

Various chemical modifications are currently being evaluated for improving the efficacy of short interfering RNA (siRNA) duplexes as antisense agents for gene silencing in vivo. Among the 2′-ribose modifications assessed to date, 2′deoxy-2′-fluoro-RNA (2′-F-RNA) has unique properties for RNA interference (RNAi) applications. Thus, 2′-F-modified nucleotides are well tolerated in the guide (antisense) and passenger (sense) siRNA strands and the corresponding duplexes lack immunostimulatory effects, enhance nuclease resistance and display improved efficacy in vitro and in vivo compared with unmodified siRNAs. To identify potential origins of the distinct behaviors of RNA and 2′-F-RNA we carried out thermodynamic and X-ray crystallographic analyses of fully and partially 2′-F-modified RNAs. Surprisingly, we found that the increased pairing affinity of 2′-F-RNA relative to RNA is not, as commonly assumed, the result of a favorable entropic contribution (‘conformational preorganization’), but instead primarily based on enthalpy. Crystal structures at high resolution and osmotic stress demonstrate that the 2′-F-RNA duplex is less hydrated than the RNA duplex. The enthalpy-driven, higher stability of the former hints at the possibility that the 2′-substituent, in addition to its important function in sculpting RNA conformation, plays an underappreciated role in modulating Watson–Crick base pairing strength and potentially π–π stacking interactions