In Vitro Antibacterial and Antioxidant Studies of Croton roxburghii L., from Similipal Biosphere Reserve

In vitro antibacterial activities of acetone, ethanol, methanol and water extracts of leaves and bark of Croton roxburghii L. studied against ten human pathogenic bacterial strains showed significantly higher activity in acetone extract and least activity in case of aqueous. Minimal inhibitory concentration (MIC) values of all extracts ranged between 0.62 and 10 mg/ml, while minimal bactericidal concentration (MBC) values ranged from 1.25 to values greater than 10 mg/ml. The antioxidant assays viz. DPPH, hydrogen peroxide scavenging, iron reducing and iron chelating assays along with total phenol and ascorbic acid content were carried out with aqueous extracts of leaves and bark. While the total phenol contents in leaves and bark extracts were 0.766 ± 0.014 and 0.735 ± 0.028% respectively their ascorbic acid contents were found to be 0.252 ± 0.019 and 0.431 ± 0.013% respectively. DPPH activities in both (leaves and bark) extracts increased with the increase in concentrations. Iron chelating capacity of leaves extract is significantly higher than that of the bark. Leaves extract showed an increase in percentage of scavenging property with the increase in concentrations. Plant extracts showed low amount of iron reducing property at all concentrations. Hydrogen peroxide scavenging properties of bark was low than that of the leaves.     

Analysis of transgene(s) (psy+crtI) inheritance and its stability over generations in the genetic background of indica rice cultivar Swarna

Rice the major staple food crop which feeds more than half of the world’s population but, lacks pathway to synthesize and accumulate provitamin A in endosperm therefore rice eaters particularly children, and pregnant women suffer due to vitamin A deficiency. The pathway for provitamin A synthesis in rice endosperm has been engineered and transgenic rice lines have yellow endosperm, called ‘Golden Rice’. The present study aimed at studying the inheritance of transgene(s) in six transgenic events of ‘Golden Rice’ and transfer of provitamin A trait from transgenic lines to a widely grown mega rice variety Swarna. The events E1, R1 and W1 showed normal Mendelian inheritance in F₂, BC₁F₁ and BC₁F₂ generations. The event W1 was studied in BC₁F₃ as well and showed normal Mendelian inheritance of 3:1. The inheritance pattern in L1 event in BC₁F₁ and BC₁F₂ showed normal Mendelian inheritance following expected ratio 1:1 and 3:1 respectively. The two events G1 and T1 showed distorted segregation in BC₁F₂ and BC₂F₂ respectively in Swarna genetic background. In G1 event, transgene inheritance showed segregation distortion in BC₁F₂ in favour of transgene negative plants. In T1 event, inheritance followed expected Mendelian segregation in BC₁F₁, BC₂F₁ and BC₂F₂, generations. However, when tested against co-dominant inheritance 1:2:1 pattern in BC₂F₂, segregation distortion was observed with less than the expected transgene homozygotes. While against 3:1 ratio, it showed the expected segregation pattern in BC₂F₂ generation. Segregation distortion probably due to differential transmission of transgene positive/negative gametes through either/both parents which needs further study.     

Depression of sink activity precedes the inhibition of biomass production in tomato plants subjected to potassium deficiency stress

Tomato [Solanum lycopersicum (formerly Lycopersicon esculentum) L. cv. Momotarou] plants were grown hydroponically inside the greenhouse of Hiroshima University, Japan. The adverse effects of potassium (K) deficiency stress on the source-sink relationship during the early reproductive period was examined by withdrawing K from the rooting medium for a period of 21 d. Fruits and stem were the major sink organs for the carbon assimilates from the source. A simple non-destructive micro-morphometric technique was used to measure growth of these organs. The effect of K deficiency was studied on the apparent photosynthesis (source activity), leaf area, partitioning (13)C, sugar concentration, K content, and fruit and stem diameters of the plant. Compared with the control, K deficiency treatment severely decreased biomass of all organs. The treatment also depressed leaf photosynthesis and transport of (13)C assimilates, but the impact of stress on these activities became evident only after fruit and stem diameter expansions were down-regulated. These results suggested that K deficiency diminished sink activity in tomato plants prior to its effect on the source activity because of a direct effect on the water status of the former. The lack of demand in growth led to the accumulation of sugars in leaves and concomitant fall in photosynthetic activity. Since accumulation of K and sugars in the fruit was not affected, low K levels of the growing medium might not have affected the fruit quality. The micro-morphometric technique can be used as a reliable tool for monitoring K deficiency during fruiting of tomato. K deficiency directly hindered assimilate partitioning, and the symptoms were considered more detrimental compared with P deficiency.     

Understanding the Effects of Molecular Dopant on n‐Type Organic Thermoelectric Properties

Molecular doping is a powerful method to fine‐tune the thermoelectric properties of organic semiconductors, in particular to impart the requisite electrical conductivity. The incorporation of molecular dopants can, however, perturb the microstructure of semicrystalline organic semiconductors, which complicates the development of a detailed understanding of structure–property relationships. To better understand how the doping pathway and the resulting dopant counterion influence the thermoelectric performance and transport properties, a new dimer dopant, (N‐DMBI)₂, is developed. Subsequently, FBDPPV is then n‐doped with dimer dopants (N‐DMBI)₂, (RuCp*mes)₂, and the hydride‐donor dopant N‐DMBI‐H. By comparing the UV–vis–NIR absorption spectra and morphological characteristics of the doped polymers, it is found that not only the doping mechanism, but also the shape of the counterion strongly influence the thermoelectric properties and transport characteristics. (N‐DMBI)₂, which is a direct electron‐donating dopant with a comparatively small, relatively planar counterion, gives the best power factor among the three systems studied here. Additionally, temperature‐dependent conductivity and Seebeck coefficient measurements differ between the three dopants with (N‐DMBI)₂ yielding the best thermoelectric properties. The results of this study of dopant effects on thermoelectric properties provide insight into guidelines for future organic thermoelectrics.     

Structural,photoluminescence and dielectric investigations of phosphatic shale

In the current study, the structural and spectroscopic properties of phosphatic shale samples obtained from the Atomic Minerals Directorate for Exploration and Research were probed for potential use as a phosphor material. X‐ray diffraction and Raman and Fourier transform infrared spectroscopy revealed that the beneficiated phosphatic shale samples were primarily monophasic consisting of fluorapatite [Ca₅(PO₄)₃F, (FAP)] with minor traces of haematite (α‐Fe₂O₃) and calcite (CaCO₃). Energy dispersive X‐ray fluorescence revealed the presence of U, Eu, Dy and Tb in the FAP matrix substituted at Ca(I) and Ca(II) sites of FAP. A reduced optical direct band gap of 4.46 eV was calculated from the Tauc plot. Photoluminescence spectral studies revealed multicolour emissions (red, yellow, green and blue) on ultraviolet light excitation that were attributed to luminescence spectra from rare earth ions Eu³⁺, Tb³⁺, U⁴⁺ and U⁶⁺ in the FAP matrix. The overall emissions for the rare earth and actinide‐doped FAP were obtained in the cool white region and the corresponding Commission Internationale de l’Eclairage chromaticity coordinates were calculated to be (0.274, 0.317). The corresponding colour correlated temperature obtained was 9342 K. Furthermore, phosphatic shale had a high room temperature dielectric constant of 11 at a frequency of 1 kHz that demonstrated its suitability for use in biological sensors. The study showed that natural phosphatic shale could be a potential material for optical, biological and dielectric applications.     

Evaluation of fluorescence in situ hybridization to detect encapsulated Bacillus pumilus SAFR-032 spores released from poly(methylmethacrylate)

Bacillus pumilus SAFR‐032 spores originally isolated from the Jet Propulsion Laboratory spacecraft assembly facility clean room are extremely resistant to UV radiation, H₂O₂, desiccation, chemical disinfection and starvation compared to spores of other Bacillus species. The resistance of B. pumilus SAFR‐032 spores to standard industrial clean room sterilization practices is not only a major concern for medical, pharmaceutical and food industries, but also a threat to the extraterrestrial environment during search for life via spacecraft. The objective of the present study was to investigate the potential of Alexa‐FISH (fluorescence in situ hybridization with Alexa Fluor® 488 labeled oligonucleotide) method as a molecular diagnostic tool for enumeration of multiple sterilant‐resistant B. pumilus SAFR‐032 spores artificially encapsulated in, and released via organic solvent from, a model polymeric material: poly(methylmethacrylate) (Lucite, Plexiglas). Plexiglas is used extensively in various aerospace applications and in medical, pharmaceutical and food industries. Alexa‐FISH signals were not detected from spores via standard methods for vegetative bacterial cells. Optimization of a spore permeabilization protocol capitalizing on the synergistic action of proteinase‐K, lysozyme, mutanolysin and Triton X‐100 facilitated efficient spore detection by Alexa‐FISH microscopy. Neither of the Alexa‐probes tested gave rise to considerable levels of Lucite‐ or solvent‐associated background autofluorescence, demonstrating the immense potential of Alexa‐FISH for rapid quantification of encapsulated B. pumilus SAFR‐032 spores released from poly(methylmethacrylate).     

SNPs in stress-responsive rice genes: validation, genotyping, functional relevance and population structure

ABSTRACT: BACKGROUND: Single nucleotide polymorphism (SNP) validation and large-scale genotyping are required to maximize the use of DNA sequence variation and determine the functional relevance of candidate genes for complex stress tolerance traits through genetic association in rice. We used the bead array platform-based Illumina GoldenGate assay to validate and genotype SNPs in a select set of stress-responsive genes to understand their functional relevance and study the population structure in rice. RESULTS: Of the 384 putative SNPs assayed, we successfully validated and genotyped 362 (94.3%). Of these 325 (84.6%) showed polymorphism among the 91 rice genotypes examined. Physical distribution, degree of allele sharing, admixtures and introgression, and amino acid replacement of SNPs in 263 abiotic and 62 biotic stress-responsive genes provided clues for identification and targeted mapping of trait-associated genomic regions. We assessed the functional and adaptive significance of validated SNPs in a set of contrasting drought tolerant upland and sensitive lowland rice genotypes by correlating their allelic variation with amino acid sequence alterations in catalytic domains and three-dimensional secondary protein structure encoded by stress-responsive genes. We found a strong genetic association among SNPs in the nine stress-responsive genes with upland and lowland ecological adaptation. Higher nucleotide diversity was observed in indica accessions compared with other rice sub-populations based on different population genetic parameters. The inferred ancestry of 16% among rice genotypes was derived from admixed populations with the maximum between upland aus and wild Oryza species. CONCLUSIONS: SNPs validated in biotic and abiotic stress-responsive rice genes can be used in association analyses to identify candidate genes and develop functional markers for stress tolerance in rice.     

Molecular Diversity in Indian Tobacco Types as Revealed by Randomly Amplified DNA Polymorphism

During the past five decades, a large number of tobacco varieties have been developed for different end uses in India through pure line selection from local land races, mutation breeding, and hybridization involving local selections and exotic introductions followed by pedigree selection. No systematic effort has been made to understand the existing diversity pattern in these varieties, which is crucial to define future breeding strategy in this important commercial crop. We characterized 46 varieties belonging to 10 different manufacturing tobacco types cultivated under different agro-climatic conditions in India along with two wild species of Nicotiana using 40 arbitrary primers in RAPID. The level of polymorphism among the varieties of N. tabacum was 59.4%, which was more than double the level observed in the other cultivated species N. rustica (25.2%). A broader range (0.64 to 0.94) of pair wise similarity measures in N. tabacum than in N. rustica (0.83 to 0.92) reflected the more diversified breeding efforts in the major cultivated species. The two wild species namely, N. glutinosa and N. gossei clustered separately from the two cultivated species. Molecular classification of the varieties corresponded largely with their manufacturing trait and parentage. RAPID markers provided sufficient resolution to distinguish among closely related tobacco types. Nine RAPID markers were found conserved across all the varieties and species. The markers found specific to the varieties can be used in correct identification of the carrier genotypes in trade and commerce. This is the first report on the molecular diversity analysis of Indian tobacco.     

Mapping of quantitative trait loci for basmati quality traits in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Traditional basmati rice varieties are very low yielding due to their poor harvest index, tendency to lodging and increasing susceptibility to foliar diseases; hence there is a need to develop new varieties combining the grain quality attributes of basmati with high yield potential to fill the demand gap. Genetic control of basmati grain and cooking quality traits is quite complex, but breeding work can be greatly facilitated by use of molecular markers tightly linked to these traits. A set of 209 recombinant inbred lines (RILs) developed from a cross between basmati quality variety Pusa 1121 and a contrasting quality breeding line Pusa 1342, were used to map the quantitative trait loci (QTLs) for seven important quality traits namely grain length (GL), grain breadth (GB), grain length to breadth ratio (LBR), cooked kernel elongation ratio (ELR), amylose content (AC), alkali spreading value (ASV) and aroma. A framework molecular linkage map was constructed using 110 polymorphic simple sequence repeat (SSR) markers distributed over the 12 rice chromosomes. A number of QTLs, including three for GL, two for GB, two for LBR, three for aroma and one each for ELR, AC and ASV were mapped on seven different chromosomes. While location of majority of these QTLs was consistent with the previous reports, one QTL for GL on chromosomes 1, and one QTL each for ELR and aroma on chromosomes 11 and 3, respectively, are being reported here for the first time. Contrary to the earlier reports of monogenic recessive inheritance, the aroma in Pusa 1121 is controlled by at least three genes located on chromosomes 3, 4 and 8, and similar to the reported association of badh2 gene with aroma QTL on chromosome 8, we identified location of badh1 gene in the aroma QTL interval on chromosome 4. A discontinuous 5 + 3 bp deletion in the seventh exon of badh2 gene, though present in all the RILs with high aroma, was not sufficient to impart this trait to the rice grains as many of the RILs possessing this deletion showed only mild or no aroma expression. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.