Ex Situ Conservation of Phyllanthus fraternus Webster and Evaluation of Genetic Fidelity in Regenerates Using DNA-Based Molecular Marker

Germplasm storage of Phyllanthus fraternus by using synseed technology has been optimized. Synseeds were prepared from nodal segments taken from in vitro-grown plantlets. An encapsulation matrix of 3 % sodium alginate and 100 mM calcium chloride with polymerization duration up to 15 min was found most suitable for synseed formation. Maximum plantlet conversion (92.5?±?2.5 %) was obtained on a growth regulator-free ½-strength solid Murashige and Skoog (MS) medium. Multiple shoot proliferation was optimum on a ½ MS medium containing 0.5 mg/l 6-benzylaminopurine (BAP). Shoots were subjected to rooting on MS media containing 1 mg/l α-naphthaleneacetic acid (NAA) and acclimatized successfully. Encapsulated nodal segments can be stored for up to 90 days with a survival frequency of 47.33 %. The clonal fidelity of synseed-derived plantlets was also assessed and compared with that of the mother plant using rapid amplified polymorphic DNA and inter-simple sequence repeat analysis. No changes in molecular profiles were observed among the synseed-derived plantlets and mother plant, which confirms the genetic stability of regenerates. This synseed production protocol could be useful for in vitro multiplication, short-term storage, and exchange of germplasm of this important antiviral and hepatoprotective plant.     

Expeditious synthesis of 5,6,7,8-tetrahydro-imidazo[1,2-a]pyrimidin-2-ones and 3,4,6,7,8,9-hexahydro-pyrimido[1,2-a]pyrimidin-2-ones

A convenient synthesis of new 5,6,7,8-tetrahydro-imidazo[1,2-a]pyrimidin-2-ones and 3,4,6,7,8,9-hexahydro-pyrimido[1,2-a]pyrimidin-2-ones from the Baylis-Hillman adducts of acrylonitrile and their derivatives is described. A common strategy employed to achieve the syntheses of title compounds involved generation of diamines from different Baylis-Hillman derivatives followed by treatment with cyanogen bromide at reflux temperature to trigger a double intramolecular cyclization.     

Triphenyltelluronium β-diketonates; Synthesis and spectra

Triphenyltelluronium /gb-diketonates, RC(O)CHC(O)R¹ (where R = CH₃, Ph or CF₃ and R¹ = CH₃, Ph, CF₃ or 2-thienyl) have been prepared. Spectral data(IR, ¹H and ¹³C NMR, mass spectroscopy) are presented and discussed in conjunction with molecular weight and conductivity data. It is concluded that weak coordination of the β-diketonate to the tellurium atom is a common structural feature of the compounds.     

Photosensitized paraquat-induced structural alterations and free radical mediated fragmentation of serum albumin

Photosensitization of paraquat with photosynthetically active radiations (PAR) induced substantial production of both the hydroxyl radicals (*OH) and superoxide anions (O(2)(*-)) under in vitro conditions. Addition of transition metal ion, Cu (II) enhanced the paraquat-induced *OH radical production by 1.8-fold. Treatment of bovine serum albumin (BSA) with photosensitized paraquat resulted in a dose dependent fragmentation of protein. The quantitative analysis revealed the release of 73 microM acid soluble amino groups and 450 microM carbonyl groups from treated albumin at the highest albumin-paraquat molar ratio of 1:8 in presence of 200 microM Cu (II). The results with the free radical quenchers such as mannitol and superoxide dismutase (SOD) clearly reflected the involvement of *OH radicals in protein fragmentation process. The fluorescence data revealed significantly higher binding of paraquat with serum albumin. The binding constants (K(a)) and binding capacity (n) of albumin for paraquat were determined to be 3.4 x 10(5) l/mole and 12.9, respectively. Fluorescence emission spectra exhibited significant quenching of the intrinsic fluorescence of albumin upon addition of paraquat at increasing molar ratios. This is attributed to induced conformational changes in protein structure upon paraquat interaction at specific sites on albumin molecule. Most likely, the alkyl group transfers occur from N1 and/or N1' positions of paraquat to the electron rich sites at critical amino acid residues on treated protein. At higher paraquat concentrations, the albumin-paraquat interaction resulted in adduct formation with concurrent protein alkylation and free radical mediated fragmentation. Thus, on the basis of these results, the paraquat-protein interaction leading to alkylation, structural alterations and/or fragmentation of biological macromolecules has been suggested as an important factor for agrochemical-induced toxicity.     

Systematics of the librational modes of water in the IR spectra of MSO4 · H2O (M = Mn,Co, Ni,Zn)

In the isomorphous hydrates MSO₄ · H₂O (M = Mn, Co, Ni, Zn), where M-O_W distance is the only variable, the frequencies of the wagging, rocking and bending modes of water and of metal-oxygen stretching have been shown to correlate smoothly with the distance r(M-O_W). Quantitative relations have been found for ν_W and ν(M-O_W) which vary linearly, while ν_R and ν^C₂ vary non-linearly with r(M-O_W).     

Asymptotic screened hydrogenic radial integrals

The screened hydrogenic radial dipole integral for discrete-discrete transitions from initial state n'l' to final state nl is asymptotically expanded to the lowest order such that the final quantum number n --> infinity. The analytical expression obtained is in terms of confluent hypergeometric functions, and explicit expressions for a few of the specific transitions are derived from them as examples.     

Separation and quantification of lignans in Phyllanthus species by a simple chiral densitometric method

A sensitive, selective, and robust high-performance TLC (HPTLC) method using chiral TLC plates for qualitative and quantitative analysis of phyllanthin (A), hypophyllanthin (B), niranthin (C), and nirtetralin (D), the active lignans of Phyllanthus species, was developed and validated. The effectiveness and role of various stationary phases viz TLC silica gel 60F(254), HPTLC silica gel 60F(254), and chiral TLC plates in the quantitation were evaluated. A precoated chiral TLC plate was found suitable for the simultaneous analysis of four pharmacologically active lignans. For achieving good separation, the optimized mobile phase of n-hexane/acetone/1,4-dioxane (9:1:0.5 by volume) was used (R(f) = 0.30, 0.36, 0.41, and 0.48 for compounds A, B, C, and D, respectively). A densitometric determination of the above compounds was carried out in reflection/absorption mode at 620 nm. Optimized chromatographic conditions provide well-separated compact bands for the tested lignans. The calibration curves were found linear in the concentration range of 100-500 ng/band. Recoveries of A-D were 99.98, 100.51, 99.22, and 98.74%, respectively. The method was validated according to ICH guidelines. The method reported here is reproducible and applied for the quantitative analysis of the above lignans in the leaves of four Phyllanthus species, i. e., P. amarus, P. maderaspatensis, P. urinaria, and P. virgatus.     

Nonequilibrium thermodynamics formalism for Marcus theory of heterogeneous and self-exchange electron-transfer rate constants

The cross-exchange electron-transfer rate constant expression of Marcus is derived from the Flux-force formalism of non-equilibrium thermodynamics. The relationship governing the Onsager's phenomenological coefficients for cross-exchange and self-exchange electron-transfer processes is deduced. Onsager's phenomenological coefficient pertaining to the Butler-Volmer equation is derived and estimated from the experimental exchange current densities. The correlation between the heterogeneous and the homogeneous electron-transfer rate constants derived by Marcus is analyzed in terms of the corresponding phenomenological coefficients.     

Siderophoregenic Bradyrhizobia boost yield of soybean

After screening for siderophore (microbial iron chelator) production, of seven available cultures of soybean (Glycine max L.) root nodule bradyrhizobia, one strain, Bradyrhizobium japonicum NCIM 2746, was selected to confirm its phytopathogenic suppression and soybean growth promotion. Based on chromatographic and spectrophotometric studies, two different siderophores, a hydroxamate type (MW 734) and another catecholate type (MW 1000), were observed. Randomized block design (RBD) analysis of sickpot studies (soil inoculated with phytopathogens) with an MACS 124 variety of soybean, bacterized with siderophoregenic B. japonicum, showed a marked increase in the percentage of germination, nodulation, chlorophyll, oil, protein content, and number of pods. Field trial study confirmed these pot results, which were evident from enhancement in shoot length, number of branches, chlorophyll content, number of nodules, root length, and number of pods. These results suggest the possibility of exploiting B. japonicum NCIM 2746 as a potential bioinoculant.     

Effect of Evolutionary Adaption on Xylosidase Activity in Thermotolerant Yeast Isolates <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis> NIRE-K1 and NIRE-K3

Efficient use of xylose along with glucose is necessary for the economic production of lignocellulosic based biofuels. Xylose transporters play an important role in the microorganisms for efficient utilization of xylose. In the present study, a novel method has been developed for a rapid assay of xylose transport activity in the xylose-utilizing isolates and other known yeasts. An assay was conducted to compare the activity of β-xylosidase using p-nitrophenyl-β-d-xylopyranoside (pNPX) in the intact, intracellular, and extracellular yeasts cells showing xylose transporter. Saccharomyces cerevisiae (MTCC 170) showed no xylosidase activity, while little growth was observed in the xylose-containing medium. Although other yeasts, i.e., Kluyveromyces marxianus NIRE-K1 (MTCC 5933), K. marxianus NIRE-K3 (MTCC 5934), and Candida tropicalis (MTCC 230), showed xylosidase activity in intact, intracellular, and extracellular culture. The xylosidase activity in intact cell was higher than that of extracellular and intracellular activity in all the yeast cells. The enzyme activity was higher in case of K. marxianus NIRE-K1 and K. marxianus NIRE-K3 rather than the C. tropicalis. Further, better xylosidase activity was observed in adapted K. marxianus cells which were 2.79–28.46 % higher than that of native (non-adapted) strains, which indicates the significant improvement in xylose transportation.