Co-inoculation of biochar and arbuscular mycorrhizae for growth promotion and nutrient fortification in soybean under drought conditions

Drought is significant abiotic stress that affects the development and yield of many crops. The present study is to investigate the effect of arbuscular mycorrhizal fungi (AMF) and biochar on root morphological traits, growth, and physiological traits in soybean under water stress. Impact of AMF and biochar on development and root morphological traits in soybean and AMF spores number and the soil enzymes' activities were studied under drought conditions. After 40 days, plant growth parameters were measured. Drought stress negatively affected soybean growth, root parameters, physiological traits, microbial biomass, and soil enzyme activities. Biochar and AMF individually increase significantly plant growth (plant height, root dry weight, and nodule number), root parameters such as root diameter, root surface area, total root length, root volume, and projected area, total chlorophyll content, and nitrogen content in soybean over to control in water stress. In drought conditions, dual applications of AMF and biochar significantly enhanced shoot and root growth parameters, total chlorophyll, and nitrogen contents in soybean than control. Combined with biochar and AMF positively affects AMF spores number, microbial biomass, and soil enzyme activities in water stress conditions. In drought stress, dual applications of biochar and AMF increase microbial biomass by 28.3%, AMF spores number by 52.0%, alkaline phosphomonoesterase by 45.9%, dehydrogenase by 46.5%, and fluorescein diacetate by 52.2%, activities. The combined application of biochar and AMF enhance growth, root parameters in soybean and soil enzyme activities, and water stress tolerance. Dual applications with biochar and AMF benefit soybean cultivation under water stress conditions.

Microbial Community and Function-Based Synthetic Bioinoculants: A Perspective for Sustainable Agriculture

Interactions among the plant microbiome and its host are dynamic, both spatially and temporally, leading to beneficial or pathogenic relationships in the rhizosphere, phyllosphere, and endosphere. These interactions range from cellular to molecular and genomic levels, exemplified by many complementing and coevolutionary relationships. The host plants acquire many metabolic and developmental traits such as alteration in their exudation pattern, acquisition of systemic tolerance, and coordination of signaling metabolites to interact with the microbial partners including bacteria, fungi, archaea, protists, and viruses. The microbiome responds by gaining or losing its traits to various molecular signals from the host plants and the environment. Such adaptive traits in the host and microbial partners make way for their coexistence, living together on, around, or inside the plants. The beneficial plant microbiome interactions have been exploited using traditional culturable approaches by isolating microbes with target functions, clearly contributing toward the host plants' growth, fitness, and stress resilience. The new knowledge gained on the unculturable members of the plant microbiome using metagenome research has clearly indicated the predominance of particular phyla/genera with presumptive functions. Practically, the culturable approach gives beneficial microbes in hand for direct use, whereas the unculturable approach gives the perfect theoretical information about the taxonomy and metabolic potential of well-colonized major microbial groups associated with the plants. To capitalize on such beneficial, endemic, and functionally diverse microbiome, the strategic approach of concomitant use of culture-dependent and culture-independent techniques would help in designing novel "biologicals" for various crops. The designed biologicals (or bioinoculants) should ensure the community's persistence due to their genomic and functional abilities. Here, we discuss the current paradigm on plant-microbiome-induced adaptive functions for the host and the strategies for synthesizing novel bioinoculants based on functions or phylum predominance of microbial communities using culturable and unculturable approaches. The effective crop-specific inclusive microbial community bioinoculants may lead to reduction in the cost of cultivation and improvement in soil and plant health for sustainable agriculture.

Biochar and Arbuscular mycorrhizal fungi mediated enhanced drought tolerance in Okra (Abelmoschus esculentus) plant growth, root morphological traits and physiological properties

Drought is a major abiotic factor limiting plant growth and crop production. There is limited information on effect of interaction between biochar and Arbuscular mycorrhizal fungi (AMF) on okra growth, root morphological traits and soil enzyme activities under drought stress. We studied the influence of biochar and AMF on the growth of Okra (Abelmoschus esculentus) in pot experiments in a net house under drought condition. The results showed that the biochar treatment significantly increased plant growth (the plant height by 14.2%, root dry weight by 30.0%) and root morphological traits (projected area by 22.3% and root diameter by 22.7%) under drought stress. In drought stress, biochar treatment significantly enhanced the chlorophyll 'a' content by 32.7%, the AMF spore number by 22.8% and the microbial biomass as compared to the control. Plant growth parameters such as plant height, shoot and root dry weights significantly increased by AMF alone, by 16.6%, 21.0% and 40.0% respectively under drought condition. Other plant biometrics viz: the total root length, the root volume, the projected area and root diameter improved significantly with the application of AMF alone by 38.3%, 60.0%,16.8% and 15.9% respectively as compared with control. Compared to the control, AMF treatment alone significantly enhanced the total chlorophyll content by 36.6%, the AMF spore number by 39.0% and the microbial biomass by 29.0% under drought condition. However, the highest values of plant growth parameters (plant height, shoot dry weight, root dry weight) and root morphological traits (the total root length, root volume, projected area, root surface area) were observed in the combined treatment of biochar and AMF treatment viz: 31.9%, 34.2%, 60.0% and 68.6%, 66.6%, 45.5%, 41.8%, respectively compared to the control under drought stress. The nitrogen content, total chlorophyll content and microbial biomass increased over un-inoculated control. The soil enzymes; alkaline phosphatase, dehydrogenase and fluorescein diacetate enzyme activities significantly increased in the combined treatment by 55.8%, 68.7% and 69.5%, respectively as compared to the control under drought stress. We conclude that biochar and AMF together is potentially beneficial for cultivation of okra in drought stress conditions.

Ionic Conductivity of Na3Al2P3O12 Glass Electrolytes-Role of Charge Compensators

In glasses, a sodium ion (Na⁺) is a significant mobile cation that takes up a dual role, that is, as a charge compensator and also as a network modifier. As a network modifier, Na⁺ cations modify the structural distributions and create nonbridging oxygens. As a charge compensator, Na⁺ cations provide imbalanced charge for oxygen that is linked between two network-forming tetrahedra. However, the factors controlling the mobility of Na⁺ ions in glasses, which in turn affects the ionic conductivity, remain unclear. In the current work, using high-fidelity experiments and atomistic simulations, we demonstrate that the ionic conductivity of the Na₃Al₂P₃O₁₂ (Si0) glass material is dependent not only on the concentration of Na⁺ charge carriers but also on the number of charge-compensated oxygens within its first coordination sphere. To investigate, we chose a series of glasses formulated by the substitution of Si for P in Si0 glass based on the hypothesis that Si substitution in the presence of Na⁺ cations increases the number of Si-O-Al bonds, which enhances the role of Na as a charge compensator. The structural and conductivity properties of bulk glass materials are evaluated by molecular dynamics (MD) simulations, magic angle spinning-nuclear magnetic resonance, Raman spectroscopy, and impedance spectroscopy. We observe that the increasing number of charge-imbalanced bridging oxygens (BOs) with the substitution of Si for P in Si0 glass enhances the ionic conductivity by an order of magnitude-from 3.7 × 10^-8 S.cm^-1 to 3.3 × 10^-7 S.cm^-1 at 100 °C. By rigorously quantifying the channel regions in the glass structure, using MD simulations, we demonstrate that the enhanced ionic conductivity can be attributed to the increased connectivity of Na-rich channels because of the increased charge-compensated BOs around the Na atoms. Overall, this study provides new insights for designing next-generation glass-based electrolytes with superior ionic conductivity for Na-ion batteries.

Realizing cool and warm white-LEDs based on color controllable (Sr,Ba)2Al3O6F:Eu2+ phosphors obtained via a microwave-assisted diffusion method

Globally, phosphor converted white-LEDs (W-LEDs) are among the most suitable sources to reduce energy consumption. Nevertheless, modernization of efficient broadband emitting phosphors is most crucial to improve the W-LED performance. Herein, we synthesized a series of novel broadband emitting Sr2-xAl3O6F:xEu2+ phosphors via a new microwave-assisted diffusion method. Rietveld refinement of the obtained X-ray diffraction results was performed to recognize the exact crystal phase and the various cationic sites. Oxygen vacancies (VO) formed under synthetic reducing conditions enabled Sr2Al3O6F to demonstrate bright self-activated bluish emission. Doping of Eu2+ ions unlocked the energy transfer process from the host to the activator ions, owing to which, the self-activated emission diminished and the Eu2+-doped sample showed amplified bluish-green emission. The gradual increase in Eu2+ concentrations regulated the controllable emissions from the bluish (0.34, 0.42) to the greenish (0.38, 0.43) zone under UV excitation. Because of the different absorption preferences of Eu2+ ions located at the different Sr2+ sites, Sr2-xAl3O6F:xEu2+ exhibited bluish-white emission under blue irradiation. A further enhancement in PL intensity had been observed by the cation substitution of Ba2+ for Sr2+ sites in the optimum Sr1.95Al3O6F:0.05Eu2+ phosphor. The as-fabricated W-LEDs utilizing the optimized Sr1.75Ba0.2Al3O6F:0.05Eu2+ phosphor exhibited a cool-white light emission along with a 372 nm NUV-LED and a 420 nm blue-LED with a moderate CRI of 70 and a CCT above 6000 K. Such cool white emission was controlled to natural white with the CCT close to 5000 K, and the CRI above 80 via utilizing a suitable red emitting phosphor. The W-LED performances of the optimized phosphor justified its applicability to produce white light for lighting applications.

Trimetallic composite nanofibers for antibacterial and photocatalytic dye degradation of mixed dye water

Membrane technology is an advanced approach to making a healthier and cleaner environment. Using such catalytic membrane technology to get clean, usable water by removal of dye impurities as well as pathogenic microbes is the main goal behind the research work. Here, we present the synthesis and efficacy study of polymethyl methacrylate (PMMA)-based Ag/ZnO/TiO₂ trimetallic bifunctional nanofibers with antibacterial and photocatalytic activity. The nanofibers have been proven to be effective for the degradation of methylene blue (MB 93.4%), rhodamine B (Rh 34.6%), auramine-O (Au 65.0%) and fuchsin basic (FB 69.8%) dyes individually within 90 min in daylight. The study is further extended in abating a mixture of these dyes from contaminated water using composite nanofibers. Also, in the case of a mixture of these dyes (3 ppm each), nanofibers show dye degradation efficiency (DDE) of 90.9% (MB), 62.4% (Au) and 90.3% (FB and Rh) in 60 min. The role of Ag nanoparticles with a synergic photocatalytic effect on ZnO and TiO₂ is also demonstrated. Also, PMMA/ZnO/TiO₂ composite fiber membrane in synergy with silver particles shows better antibacterial activity against Gram-negative bacteria E. coli, making PMMA/Ag/ZnO/TiO₂ fibers a promising candidate in water purification.

Influence of gold nanoparticles on the nonlinear optical and photoluminescence properties of Eu2O3 doped alkali borate glasses

Alkali borate glasses activated with trivalent europium ions and rooted with gold (Au) nanoparticles (NPs) were synthesised through a melt quenching process involving a selective thermochemical reduction and their applicability as photonic materials was assessed in detail. Non-linear optical (NLO) measurements were performed using a Z-scan approach in the wavelength range of 700-1000 nm. The open aperture Z-scan signatures for the Eu³⁺-containing glasses embedded with and without the Au NPs established a reverse saturable absorption (RSA) at all of the studied wavelengths ascribed to the two-photon absorption (2PA). Surprisingly, the nonlinear optical absorption switched to a saturable absorption (SA) with an increase in the concentration of AuCl₃. With the incorporation of the Au NPs, the UV excited photoluminescence (PL) intensity of the Eu³⁺-doped glasses increased first as a consequence of the local field enhancement by the Au NPs, and subsequently decreased at a higher concentration of AuCl₃ due to the reverse energy transfer from the Eu³⁺ ion to the Au⁰ NPs. The electronic polarization effect of the host glass enhanced the ⁵D₀→⁷F₄ transition intensity on the incorporation of the gold NPs owing to the gold NP-embedded glasses showing a deep-red emission. The NLO and PL studies suggested that the investigated glasses containing a 0.01 mol% of AuCl₃ is practically appropriate for photonic applications.

Multi-trait PGP rhizobacterial endophytes alleviate drought stress in a senescent genotype of sorghum [Sorghum bicolor (L.) Moench]

Root-tissue colonizing bacteria demonstrated with multiple PGP traits from sorghum plants were identified as Ochrobactrum sp. EB-165, Microbacterium sp. EB-65, Enterobacter sp. EB-14 and Enterobacter cloacae strain EB-48 on the basis of 16S rRNA gene sequencing. Here, the in vivo experiments using ½-MS media and ½-MS media + 15% PEG 8000 (for inducing drought stress) indicated stress tolerance imparting ability of these rhizobacterial endophytes in a non-stay green and senescent genotype (R-16) of sorghum. In the experiment with sterile soilrite mix base, seed bacterization with these isolates showed improved plant growth specifically the roots, in terms of root length (~ 44.2 to 50.8% over controls), root dry weight (~ 91.3 to 99.8% over controls) and root surface area (~ 1 to 1.5 fold over controls) under drought stress. Rhizobacterial endophytes were successful, not only in providing better cellular osmotic adjustment in leaves (≥ 1-fold increase in proline accumulation over controls), but favorable physiological responses like Relative Water Content (RWC) and cell Membrane Stability Index (MSI) in the inoculated plants during the drought stress induction. Up-regulation of drought responsive genes like sbP5CS2 and sbP5CS1 was observed in these endophytes-treated plants as compared to untreated control and Escherichia coli DH5α (negative control)-treated plants. Interestingly, the stress imparting traits of rhizobacterial endophytes, including up-regulation of specific genes, were observed during sorghum seedling growth only under drought stresses. The results of this study lead to the conclusion that the potential endophytic rhizobacterial interactions can contribute to plant growth promotion as well as induced stress tolerance in sorghum.

Structure and Stability of High CaO- and P2O5-Containing Silicate and Borosilicate Bioactive Glasses

The present work elucidates about the structure of bioactive glasses having chemical compositions expressed as (mol %) (50.0 - x)SiO₂-xB₂O₃-9.3Na₂O-37CaO-3.7P₂O₅, where x = 0.0, 12.5, 25, and 37.5, and establishes a correlation between the structure and thermal stability. The structural modifications in the parent boron-free glass (B0) with the gradual substitutions of B₂O₃ for SiO₂ are assessed by Raman and ²⁹Si, ³¹P, ¹¹B, and ²³Na magic angle spinning (MAS)-nuclear magnetic resonance (NMR) spectroscopies. The structural studies reveal the presence of Q_Si² and Q_Si³ structural units in both silicate and borosilicate glasses. However, Q_Si⁴(3B) units additionally form upon incorporating B₂O₃ in B0 glass. B-containing silicate glasses exhibit both three-coordinated boron (B^III) and four-coordinated boron (B^IV) units. The ³¹P MAS-NMR studies reveal that the majority of phosphate species exist as isolated orthophosphate (Q_P⁰) units. The incorporation of B₂O₃ in B0 glass increases the cross-linking between the SiO₄ and BO₄ structural units. However, incorporation of B₂O₃ lowers the glass thermal stability (ΔT), as shown by differential scanning calorimetry. Although both silicate and borosilicate glasses exhibit good in vitro apatite-forming ability and cell compatibility, the bactericidal action against Escherichia coli bacteria is more evident in borosilicate glass in comparison to silicate base glass. The controlled release of (BO₃)^3- ions from boron-modified bioactive glasses improves both the cell proliferation and the antibacterial properties, making them promising for hard tissue engineering applications.

Enhancing the effectiveness of zinc, cadmium, and lead phytoextraction in polluted soils by using amendments and microorganisms

For remediating polluted soils, phytoextraction of metals received considerable attention in recent years, although slow removal of metals remained a major constraint in this approach. We, therefore, studied the effect of selected organic and inorganic amendments on the solubility of zinc (Zn), cadmium (Cd), and lead (Pb) in polluted soil and enhancing the efficacy of phytoextraction of these metals by Indian mustard (Brassica juncea cv. Pusa Vijay). For this purpose, a greenhouse experiment was conducted using a metal-polluted soil to evaluate the effect of amendments, viz. green manure (T2), EDTA (T3), sulfur (S)+S oxidizing bacteria (Thiobacillus spp.) (T4), metal-solubilizing bacteria (Pseudomonas spp.) (T5), and green manure + metal-solubilizing bacteria (T6), on solubility and bioavailability of Zn, Cd, and Pb. Distribution of metals in different soil fractions revealed that Cd content in water soluble + exchangeable fraction increased to the extent of 34.1, 523, 133, 123, and 75.8% in T2, T3, T4, T5, and T6 treatments, respectively, over control (T1). Cadmium concentrations in soil solution as extracted by Rhizon sampler were recorded as 3.78, 88.1, 11.2, 6.29, and 4.27 μg L^-1in T2, T3, T4, T5, and T6, respectively, whereas soil solution concentration of Cd in T1 was 0.99 μg L^-1. Activities of Cd (pCd²⁺) in Baker soil extract were 12.2, 10.9, 6.72, 7.74, 7.67, and 7.05 for T1, T2, T3, T4, T5, and T6, respectively. Cadmium contents in shoot were recorded as 2.74, 3.12, 4.03, 4.55, 4.68, and 4.63 mg kg^-1 in T1, T2, T3, T4, T5, and T6 treatments, respectively. Similar trend in Zn and Pb content with different magnitude was also observed across the different amendments. Cadmium uptake by shoot of mustard was enhanced to the extent of 125, 62.5, 175, 175, and 212% grown on T2-, T3-, T4-, T5-, and T6-treated soil, respectively, over T1. By and large, free ion activity of metals as measured by Baker soil test proved to be the most effective index for predicting Zn, Cd, and Pb content in shoot of mustard, followed by EDTA and DTPA. Among the metal fractions, only water soluble + exchangeable metal contributed positively towards plant uptake, which explained the variation in shoot Zn, Cd, and Pb content to the extent of 74, 81, and 87%, respectively, along with other soil metal fractions. Risk to human health for intake of metals through the consumption of leafy vegetable (mustard) grown on polluted soil in terms of hazard quotient (HQ) ranged from 0.64 to 1.10 for Cd and 0.11 to 0.34 for Pb, thus rendering mustard unfit for the human consumption. Novelty of the study mainly consisted of the use of natural means and microorganisms for enhancing solubility of metals in soil with the ultimate aim of hastening the phytoremediation.

Diversity and Tissue Preference of Osmotolerant Bacterial Endophytes Associated with Pearl Millet Genotypes Having Differential Drought Susceptibilities

Genetic and functional diversity of osmotolerant bacterial endophytes colonizing the root, stem, and leaf tissues of pearl millet genotypes differing in their drought susceptibility was assessed. Two genotypes of pearl millet, viz., the drought tolerant genotype TT-1 and the drought susceptible genotype PPMI-69, were used in the present study. Diazotrophs were found to be the predominant colonizers, followed by the Gram positive bacteria in most of the tissues of both the genotypes. Higher proportion of bacterial endophytes obtained from the drought tolerant genotype was found to be osmotolerant. Results of 16S rRNA gene-ARDRA analysis grouped 50 of the highly osmotolerant isolates into 16 clusters, out of which nine clusters had only one isolate each, indicating their uniqueness. One cluster had 21 isolates and remaining clusters were represented by isolates ranging from two to four. The representative isolates from each cluster were identified, and Bacillus was found to be the most prevalent osmotolerant genera with many different species. Other endophytic bacteria belonged to Pseudomonas sp., Stenotrophomonas sp., and Macrococcus caseolyticus. High phylogenetic diversity was observed in the roots of the drought tolerant genotype while different tissues of the drought susceptible genotype showed less diversity. Isolates of Bacillus axarquiensis were present in all the tissues of both the genotypes of pearl millet. However, most of the other endophytic bacteria showed tissue/genotype specificity. With the exception of B. axarquiensis and B. thuringiensis, rest all the species of Bacillus were found colonizing only the drought-tolerant genotype; while M. caseolyticus colonized all the tissues of only the drought susceptible genotype. There was high incidence of IAA producers and low incidence of ACC deaminase producers among the isolates from the root tissues of the drought-tolerant genotype while reverse was the case for the drought-susceptible genotype. Thus, host played an important role in the selection of endophytes based on both phylogenetic and functional traits.

QoS Maintenance in Cognitive Radio Networks with Priority-Supporting Novel Channel Allocation Method

Satisfying the Quality of Service (QoS) is often a challenge in cognitive radio networks, because they depend on opportunistic channel accessing. In this context, appropriate pricing of vacant channels that is linked to the preference in their allocation, is found to be useful. However, ambiguity on the possible price at which the channel would be allotted is still a concern. In this work, an auction mechanism in which maximum value of the bid is predefined is proposed. With this, users quote their bid values as per their needs of getting the channels, up to the predefined maximum allowed bid price. However, final price of allocation is decided based on the sum total demand from all the users and the availability of vacant channels. Performance of the system is found in terms of blocking probabilities of secondary users and revenues to primary users. The proposed system is found to yield similar quantum of revenues as that of the Generalized Second Price (GSP) auction, while offering much lesser blocking probabilities to high-priority users to satisfy their QoS requirements.

Whole genome shotgun sequence of Bacillus paralicheniformis strain KMS 80, a rhizobacterial endophyte isolated from rice (Oryza sativa L.)

Bacillus paralicheniformis strain KMS 80 (MTCC No. 12704) is an isolate from the root tissues of rice (Oryza sativa L.) that displays biological nitrogen fixation and plant growth promoting abilities. Here, we report the complete genome sequence of this strain, which contains 4,566,040 bp, 4424 protein-coding genes, 8692 promoter sequences, 67 tRNAs, 20 rRNA genes with six copies of 5S rRNAs along with a single copy of 16S-23S rRNA and genome average GC-content of 45.50%. Twenty one genes involved in nitrogen metabolism pathway and two main transcriptional factor genes, glnR and tnrA responsible for regulation of nitrogen fixation in Bacillus sp. were predicted from the whole genome of strain KMS 80. Analysis of the ~ 4.57 Mb genome sequence will give support to understand the genetic determinants of host range, endophytic colonization behaviour as well as to enhance endophytic nitrogen fixation and other plant beneficial role of B. paralicheniformis in rice.

Structural elucidation of NASICON (Na3Al2P3O12) based glass electrolyte materials: effective influence of boron and gallium

Understanding the conductivity variations induced by compositional changes in sodium super ionic conducting (NASICON) glass materials is highly relevant for applications such as solid electrolytes for sodium (Na) ion batteries.

Comparative conventional and phenomics approaches to assess symbiotic effectiveness of Bradyrhizobia strains in soybean (Glycine max L. Merrill) to drought

Symbiotic effectiveness of rhizobitoxine (Rtx)-producing strains of Bradyrhizobium spp. in soybean (cultivar NRC-37/Ahilya-4) under limited soil moisture conditions was evaluated using phenomics tools such as infrared(IR) thermal and visible imaging. Red, green and blue (RGB) colour pixels were standardized to analyse a total of 1017 IR thermal and 692 visible images. Plants inoculated with the Rtx-producing strains B. elkanii USDA-61 and USDA-94 and successive inoculation by B. diazoefficiens USDA-110 resulted in cooler canopy temperatures and increased canopy greenness. The results of the image analysis of plants inoculated with Rtx-producing strains were correlated with effective nodulation, improved photosynthesis, plant nitrogen status and yield parameters. Principal component analysis (PCA) revealed the reliability of the phenomics approach over conventional destructive approaches in assessing the symbiotic effectiveness of Bradyrhizobium strains in soybean plants under watered (87.41-89.96%) and water-stressed (90.54-94.21%) conditions. Multivariate cluster analysis (MCA) revealed two distinct clusters denoting effective (Rtx) and ineffective (non-Rtx) Bradyrhizobium inoculation treatments in soybean. Furthermore, correlation analysis showed that this phenotyping approach is a dependable alternative for screening drought tolerant genotypes or drought resilience symbiosis. This is the first report on the application of non-invasive phenomics techniques, particularly RGB-based image analysis, in assessing plant-microbe symbiotic interactions to impart abiotic stress tolerance.

Al2O3 influence on structural, elastic, thermal properties of Yb(3+) doped Ba-La-tellurite glass: evidence of reduction in self-radiation trapping at 1μm emission

Ba-La-tellurite glasses doped with Yb(3+) ions have been prepared through melt quenching technique by modifying their composition with the inclusion of varied concentration of Al2O3 to elucidate its effects on glass structural, elastic, thermal properties and Yb(3+) ion NIR luminescence performance. The FTIR spectral analysis indicates Al2O3 addition is promoting the conversion of BOs from NBOs which have been generated during the process of depolymerisation of main glass forming TeO4 units. The elastic properties of the glass revealed an improved rigidity of the glass network on addition of Al2O3. In concurrence to this, differential thermal analysis showed an increase in glass transition temperature with improved thermal stability factor. Also, Yb(3+) fluorescence dynamics demonstrated that, Al2O3 inclusion helps in restraining the detrimental radiation trapping of ∼1μm emission.

Prosthodontic approach to treat obstructive sleep apnea

Sleep disordered breathing represents a continuum, ranging from simple snoring sans sleepiness, upper-airway resistance syndrome, obstructive sleep apnea (OSA) syndrome, to hypercapnic respiratory failure. Fifty seven articles formed the initial database and a final total of 50 articles were selected to form this review report. Four months were spent on the collection and retrieval of the articles. Articles were selected based on accuracy and evidence in the scientific literature. Oral appliances (OAs) are indicated for use in patients with mild to moderate OSA who prefer them to continuous positive airway pressure (CPAP) therapy, or for those who do not respond to, are not appropriate candidates for, or for those who have failed treatment attempts with CPAP. OAs protrude the mandible and hold it in a forward and downward position. As a consequence, the upper airway enlarges antero-posteriorly and laterally, improving its stability. Although OA are effective in some patients with OSA, they are not universally suitable. Compliance with OAs depends mainly on the balance between the perception of benefit and the side effects. In conclusion, marked variability is illustrated in the individual response to OA therapy and hence the treatment outcome is subjective.

Dynamics of soil diazotrophic community structure, diversity, and functioning during the cropping period of cotton (Gossypium hirsutum)

The soil sampled at different growth stages along the cropping period of cotton were analyzed using various molecular tools: restriction fragment length polymorphism (RFLP), terminal restriction length polymorphism (T-RFLP), and cloning-sequencing. The cluster analysis of the diazotrophic community structure of early sampled soil (0, 15, and 30 days) was found to be more closely related to each other than the later sampled one. Phylogenetic and diversity analysis of sequences obtained from the first (0 Day; C0) and last soil sample (180 day; C180) confirmed the data. The phylogenetic analysis revealed that C0 was having more unique sequences than C180 (presence of γ-Proteobacteria exclusively in C0). A relatively higher richness of diazotrophic community sequences was observed in C0 (S(ACE) : 30.76; S(Chao1) : 20.94) than C180 (S(ACE) : 18.00; S(Chao1) : 18.00) while the evenness component of Shannon diversity index increased from C0 (0.97) to C180 (1.15). The impact of routine agricultural activities was more evident based on diazotrophic activity (measured by acetylene reduction assay) than its structure and diversity. The nitrogenase activity of C0 (1264.85 ± 35.7 ηmol of ethylene production g(-1) dry soil h(-1) ) was statistically higher when compared to all other values (p < 0.05). There was no correlation found between diazotrophic community structure/diversity and N2 fixation rates. Thus, considerable functional redundancy of nifH was concluded to be existing at the experimental site.

Enhanced 2 μm broad-band emission and NIR to visible frequency up-conversion from Ho3+/Yb3+ co-doped Bi2O3-GeO2-ZnO glasses

In this work, a new and non-conventional oxide glass composition based on Bi2O3-GeO2-ZnO system has been formulated with an aim to realize low phonon oxide glass and elucidate its performance when co-doped with Ho(3+)/Yb(3+) for the energy transfer based NIR emission at 2 μm from Ho(3+) ions under Yb(3+) excitation. The glass with 1.0 mol% Ho2O3 and 0.5 mol% Yb2O3 has exhibited maximum energy transfer rate (3602 s(-1)) and energy transfer efficiency (65.92%). Important radiative properties have been predicted for emission transitions of Ho(3+) ions using intensity parameters derived from measured absorption spectra using standard Judd-Ofelt theory. At lower acceptor ion concentration (0.1 mol%), an efficient NIR to visible up-conversion emission has been observed based on two photon absorption process which has found to be reduced significantly at higher Ho(3+) concentrations with simultaneous enhancement in 2 μm emission. Hence, this newly developed glass codoped with Yb(3+)/Ho(3+) is promising glass for sensitized 2 μm emission applications as broad band tunable lasers because of the combination of low phonon energy (707 cm(-1)), high energy transfer efficiency, moderately high emission cross-section (5.33×10(-21) cm(2)) and larger effective half-width of the emission band value of 169 nm.

Cadinene sesquiterpenes from Eupatorium adenophorum and their antifungal activity

Bioactive constituents of Eupatorium adenophorum were investigated for antifungal activity. A structure-antifungal activity relationship of cadinene sesquiterpenes was predicted by evaluating individual derivatives. Cadinene derivatives were extracted from leaves of Eupatorium adenophorum using ethyl acetate. Five cadinene sesquiterpenes were isolated by column chromatography and Preparative Thin Layer Chromatography. Bioactivity of these cadinene sesquiterpenes were evaluated in vitro against four phytopathogenic fungi using poison food technique. Purified sesquiterpenes were spectroscopically elucidated as cadinan-3-ene-2,7-dione (1), 7-hydroxycadinan-3-ene-2-one (2), 5,6-dihydroxycadinan-3-ene-2,7-dione (3), cadinan-3,6-diene-2,7-dione (4) and 2-acetyl-cadinan-3,6-diene-7-one (5). Antifungal evaluation of these compounds against pathogenic fungi was found to be selective. Compound 1 was highly inhibitory towards S. rolfsii (ED50 181.60 ± 0.58 μgmL(-1)) and R. solani (ED50 189.74 ± 1.03 μgmL(-1)). Availability of plant material and significant antifungal activity makes the plant a potential source of antifungal agent and that can be exploited for the development of a natural fungicide.

Study on Tb3+ containing high silica and low silica calcium aluminate glasses: Impact of optical basicity

Two series of glasses based on high silica (CAS) and low silica calcium aluminates (LSCA) have been investigated for their structural, optical and Tb(3+) luminescence properties. The compositional modification reduces host phonon energy in LSCA glasses. Still, LSCA glasses exhibit Tb(3+) green luminescence quenching, whereas no quenching observed in CAS glasses. Material property influence on this behaviour has been discussed with an insight into the redox state of active ions.

Isolation and partial characterization of antibacterial lipopeptide produced by Paenibacillus polymyxa HKA-15 against phytopathogen Xanthomonas campestris pv. phaseoli M-5

An antibacterial metabolite was isolated from Paenibacillus polymyxa HKA-15, a soybean bacterial endophyte. The purification of the crude metabolite from Paenibacillus polymyxa HKA-15 was done by column chromatography. In TLC, a spot with an R ( f ) value of 0.86 (±0.02) from the purified fraction showed bioactivity against Xanthomonas campestris pv. phaseoli M-5. In SDS-PAGE, the purified antibiotic was separated in the molecular weight range of 3.5 kDa. The exact molecular weight of the active compound was identified as 1,347.7 Da using MS-MS analysis. Infra red spectrum and (1)H NMR analysis showed the presence of amino acids and fatty acids in the active compound. The characterization of the antibacterial compound revealed its lipopeptide nature. In an agar diffusion assay, the crude metabolite showed a broad spectrum of activity, being able to inhibit the growth of the fungal pathogen, Rhizoctonia bataticola, Macrophomina phaseolina and Fusarium udum. A stronger inhibition was observed against bacterial pathogens viz., X. campestris pv.phaseoli M-5, X. campestris pv. phaseoli CP-1-1, Xanthomonas oryzae, Ralstonia solanacearum and Micrococcus luteus.

Isolation of Rhizobacteria from Jatropha curcas and characterization of produced ACC deaminase

Decreased levels of ACC (1-aminocyclopropane-1-carboxylic acid) result in lower levels of endogenous ethylene, which eliminate the potentially inhibitory effects of stress-induced higher ethylene concentrations. It is worth noting the substantial ability of the bacterial species to colonize different environments, including taxonomically distinct plants cultivated in distantly separated geographical regions. For example, Enterobacter cloacae, designated as MSA1 and Enterobacter cancerogenus, designated as MSA2 were recovered from the rhizosphere of Jatropha in the present work. This study first time confirms the ACC deaminase activity in the Enterobacter cancerogenus on the preliminary basis. Several bacterial plant growth-promoting mechanisms were analyzed and detected like phosphate solubilization, siderophore production, IAA production, GA(3) (gibberellic acid) production and ACC deaminase activity in the isolated cultures. Isolates were grown until exponential growth phase to evaluate their ACC deaminase activity and the effect of pH, temperature, salt, metals and substrate concentration after the partial purification of enzyme by ion exchange chromatography. The FOURIER TRANSFORM INFRARED (FT-IR) spectra were recorded for the confirmation of α-ketobutyrate production. By using lineweaver Burk plot K(m) and V(max) value for ACC deaminase of both the organism was calculated in the different fractions. In this work, we discuss the possible implications of these bacterial mechanisms on the plant growth promotion or homeostasis regulation in natural conditions.

Impact of long-term wastewater application on microbiological properties of vadose zone

Impact of wastewater irrigation on some biological properties was studied in an area where treated sewage water is being supplied to the farmers since 1979 in the western part of National Capital Territory of New Delhi under Keshopur Effluent Irrigation Scheme. Three fields were selected which had been receiving irrigation through wastewater for last 20, 10 and 5 years. Two additional fields were selected in which the source of irrigation water was tubewell. The soil bacterial and fungal population density was studied in soil layers of 0-15, 15-30, 30-60 and 60-120 cm depths. Groundwater samples were collected from the piezometers installed in the field irrigated with sewage water for last 20, 10 and 5 years. Results indicate that there was significant increase in bacterial and fungal count in sewage-irrigated soils as compared to their respective control. The population density of bacteria and fungi in waste water-irrigated soils increased with the duration of sewage water application and decreased with increasing depth. The bacterial and fungal count was also directly proportional to organic carbon, sand and silt content and negatively correlated to the clay content, electrical conductivity, pH and bulk density of the soil. Groundwater under sewage-irrigated fields had higher values of most probable number (MPN) index as compared to that of tubewell water-irrigated fields. All the shallow and deep groundwaters were found to be contaminated with faecal coliforms. The vadose zone had filtered the faecal coliform to the tune of 98-99%, as the MPN index was reduced from ≥18,000 per 100 ml of applied waste water to 310 per 100 ml of groundwater under 20 years sewage-irrigated field. The corresponding values of MPN were 250 and 130 per 100 ml of shallow groundwater under 10 and 05 years sewage-irrigated fields, respectively. Rapid detection of faecal contamination suggested that the Citrobacter freundii and Salmonella were dominant in shallow groundwater, while Escherichia coli was dominant in deep groundwater collected from sewage-irrigated field.

Antibacterial activity of metabolite produced by Paenibacillus polymyxa strain HKA-15 against Xanthomonas campestris pv. phaseoli

An antibacterial metabolite extracted from Paenibacillus polymyxa HKA-15 showed strong inhibition against Xanthomonas campestris pv. phaseoli strains CP-1-1 and M-5. Minimum inhibitory concentration (MIC) of crude extract against strains CP-1-1 and M-5 was found to be 1.7 mg/ml and 1.52 mg/ml, respectively. In UV-Vis range, the absorption peak of crude extract was maximum at 240 nm. The compound is resilience to wide range of temperature, pH, surfactants and organic solvents. The complete loss of activity was observed when crude metabolite was treated with pepsin (400 unit/ml). Characterization of crude metabolite suggested its hydrophobic and peptide nature. Inhibition of Xanthomonas campestris pv. phaseoli by peptide like metabolite produced by Paenibacillus polymyxa strain HKA-15 under in vitro conditions showed ecological and biotechnological potential of strain HKA-15 to control common blight disease in beans.

Optical and dielectric properties of isothermally crystallized nano-KNbO3 in Er3+-doped K2O-Nb2O5-SiO2 glasses

Precursor glass of composition 25K(2)O-25Nb(2)O(5)-50SiO(2) (mol%) doped with Er(2)O(3) (0.5 wt% in excess) was isothermally crystallized at 800 degrees C for 0-100 h to obtain transparent KNbO(3) nanostructured glass-ceramics. XRD, FESEM, TEM, FTIRRS, dielectric constant, refractive index, absorption and fluorescence measurements were carried out to analyze the morphology, dielectric, structure and optical properties of the glass-ceramics. The crystallite size of KNbO(3) estimated from XRD and TEM is found to vary in the range 7-23 nm. A steep rise in the dielectric constant of glass-ceramics with heat-treatment time reveals the formation of ferroelectric nanocrystalline KNbO(3) phase. The measured visible photoluminescence spectra have exhibited green emission transitions of (2)H(11/2), (4)S(3/2)-->(4)I(15/2) upon excitation at 377 nm ((4)I(15/2)-->(4)G(11/2)) absorption band of Er(3+) ions. The near infrared (NIR) emission transition (4)I(13/2)-->(4)I(15/2) is detected around 1550 nm on excitation at 980 nm ((4)I(15/2)-->(4)I(11/2)) of absorption bands of Er(3+) ions. It is observed that photoluminescent intensity at 526 nm ((2)H(11/2)-->(4)I(15/2)), 550 nm ((4)S(3/2)-->(4)I(15/2)) and 1550 nm ((4)I(13/2)-->(4)I(15/2)) initially decrease and then gradually increase with increase in heat-treatment time. The measured lifetime (tau(f)) of the (4)I(13/2)-->(4)I(15/2) transition also possesses a similar trend. The measured absorption and fluorescence spectra reveal that the Er(3+) ions gradually enter into the KNbO(3) nanocrystals.

Biocontrol potential of soybean bacterial endophytes against charcoal rot fungus, Rhizoctonia bataticola

A total of 137 bacterial isolates from surface sterilized root, stem, and nodule tissues of soybean were screened for their antifungal activity against major phytopathogens like Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium udam, and Sclerotium rolfsii. Nine bacterial endophytes suppressed the pathogens under in vitro plate assay. These were characterized biochemically and identified at the genus level based on their partial sequence analysis of 16S rDNA. Eight of the isolates belonged to Bacillus and one to Paenibacillus. The phylogenetic relationship among the selected isolates was studied and phylogenetic trees were generated. The selected isolates were screened for biocontrol traits like production of hydrogen cyanide (HCN), siderophore, hydrolytic enzymes, antibiotics, and plant growth promoting traits like indole 3-acetic acid production, phosphate solubilization, and nitrogen fixation. A modified assessment scheme was used to select the most efficient biocontrol isolates Paenibacillus sp. HKA-15 (HKA-15) and Bacillus sp. HKA-121 (HKA-121) as potential candidates for charcoal rot biocontrol as well as soybean plant growth promotion.

Role of antibiosis in suppression of charcoal rot disease by soybean endophyte Paenibacillus sp. HKA-15

Four defective (AFM(-)) mutants of Paenibacillus sp. HKA-15 that no longer produced the peptide antifungal metabolites were developed through ethyl methane sulfonate (EMS) mutagenesis and used for in vivo experimentation. Reduced percentage of seed germination by mutants DM1 and DM2 (22.5% and 25%, respectively) and a high percent of disease incidence (69.3% and 67%, respectively) compared to wild-strain HKA-15 (80% seed germination and 27% disease incidence) indirectly indicated the role of peptide metabolite on disease suppression. Plants treated with AFM(-) clones showed stunted growth and the presence of pepperlike microsclerotia in the stem tissues. Light and scanning electron microscopic studies clearly showed the effect of peptide antibiosis on hyphal morphology. Exposure to crude extracts of antibiotics produced abnormal contraction of fungal cytoplasm, granulation, and fragmentation of hyphal mycelia and cell lysis. The presence of bacterial cells in the lumen of degrading fungal mycelium suggested a direct involvement of Paenibacillus sp. HKA-15 in the lysis of Rhizoctonia bataticola.

Verification and rapid identification of soybean rhizobia in Indian soils

Sixty root nodule isolates of soybean rhizobia indigenous to eight field sites in India were characterized using PCR-RFLP for repeated sequence RSalpha a 1195-bp DNA fragment, indole acetic acid production, and nitrogenase activity. Site-dependent variations were observed in terms of IAA production and nitrogenase activities. RSalpha was conserved in slow-growing soybean rhizobia across locations and sites and was absent in other Rhizobiaceae members and other bacterial genera. The results suggest that RSalpha can be a useful molecular marker for slow-growing soybean rhizobia. The study also showed the low presence of soybean nodulating fast growers in Indian soils.

Differential methods of inoculation of plant growth-promoting rhizobacteria induce synthesis of phenylalanine ammonia-lyase and phenolic compounds differentially in chickpca

Foliar spray and micro-injection of plant growth-promoting rhizobacterial species, viz. Pseudomonas fluorescens and P. aeruginosa on chickpea induced synthesis of phenylalanine ammonia-lyase (PAL) when tested against Sclerotinia sclerotiorum. Induction of PAL was also associated with increased synthesis of phenolic compounds such as tannic, gallic, caffeic, chlorogenic and cinnamic acids. Treatment with P. fluorescens was found to be more effective in inducing phenolic compounds as compared to P. aeruginosa. However, persistence of PAL activity was observed more with P. aeruginosa. Although both the inoculation methods were effective, foliar application was found to be superior to micro-injection in terms of rapid PAL activity leading to the synthesis of phenolic compounds.

Isolation and identification of natural endophytic rhizobia from rice (Oryza sativa L.) through rDNA PCR-RFLP and sequence analysis

Three novel endophytic rhizobial strains (RRE3, RRE5, and RRE6) were isolated from naturally growing surface-sterilized rice roots. These isolates had the ability to nodulate common bean (Phaseolus vulgaris). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing of 16S rDNA of these isolates revealed that RRE3 and RRE5 are phylogenetically very close to Burkholderia cepacia complex, whereas RRE6 has affinity with Rhizobium leguminosarum bv. phaseoli. Plant infection test using gusA reporter gene-tagged construct of these isolates indicated that bacterial cells can go inside and colonize the rice root interiors. A significant increase in biomass and grain yield was also recorded in greenhouse-grown rice plants inoculated with these isolates.

Molecular aspects of soybean cultivar-specific nodulation by Sinorhizobium fredii USDA257

Sinorhizobium fredii USDA257 forms nitrogen-fixing nodules in association with the primitive soybean cultivar 'Peking' but fails to initiate nodules on many advanced soybean cultivars, including 'McCall'. This distinction is controlled by a set of nodulation genes termed nolXWBTUV. Inactivation of any of these genes enables USDA257 to nodulate McCall and many other improved soybean cultivars. Mutation in the nolXWBTUV locus also alters the Nod factor structure resulting in the production of a novel molecule with glucose incorporated into the chitin backbone. Some of the genes located in the nolXWBTUV locus reveal sequence homologies to known components of the type III secretion system (TTSS) of plant and animal pathogenic bacteria. Recent studies have demonstrated the presence of a complete TTSS in USDA257 and few other symbiotic bacteria. The TTSS cluster of USDA257 contains 27 open reading frames out of which 10 code for the structural components of the TTSS. USDA257, when grown in presence of flavonoids, secrete several proteins called Nops (Nodulation Outer Proteins) into the extracellular environment. Genes located in the TTSS of USDA257 encode some of the extracellular proteins, such as NopX, NopB, and NopL. These type III secreted proteins appear to play an important role in regulating nodulation in a host-dependent manner. Failure to elaborate the Nops results in a drastic phenotypic effect on soybean nodulation, indicating that these proteins may play a pivotal role in soybean cultivar specificity. The secretion of Nops appears to be facilitated by novel filamentous appendages (pili) that are produced by USDA257 upon induction by flavonoids. Biochemical studies have demonstrated the close association of several Nops with the purified pili. However, it remains to be seen if the filamentous appendages can function as conduits for delivery of Nops into the host cell. This review examines the current state of our knowledge on the molecular aspects of soybean cultivar-specific nodulation by USDA257.

Temperature dependent luminescence characteristics of Sm3+-doped silicate glass

We report here on the optical characterisation of Sm3+ (5 wt%): SiO2 + Al2O3 + Li2O + Na2O + MgO glass from the measurements of optical absorption spectra (at 300 K), total luminescence spectra (10-300 K) and fluorescence lifetimes (10-300 K) of the prominent emission transitions of the Sm3+ ions. Besides its spectral properties, physical and nonlinearity characterising property parameters have also been computed to understand the optical dispersive power of this glass. By the application of Judd-Ofelt parameters (omega(lambda)) of the measured absorption spectrum, the radiative transition probability factors (A) and stimulated emission cross-section (sigma(p)E) of the observed fluorescent levels have been analysed. Both emission intensity and measured lifetimes of the prominent luminescent transition (4G(5/2) --> 6H(7/2)) concerning Sm3+-glass has been showing a descending trend with the rise in temperature with N2-laser (337.1 nm) as the source of excitation.