Guaianolides from Saussurea affinis

Cynaropicrin, 11βH-11,13-dihydrodesacylcynaropicrin, aguerins A and B, isoamberboin and the new guaianolides saussureolide and 11βH-11,13-dihydrodesacylcynaropicrin 8-β-d-glucoside were isolated from Saussurea affinis.     

Resonance Raman spectroscopy of horseradish peroxidase derivatives and intermediates with excitation in the near ultraviolet

Resonance Raman enhancement of derivatives and intermediates of horseradish peroxidase in the near ultraviolet (N-band excitation) results in intensity and enhancement patterns that are different from those normally observed within the porphyrin Soret (B-band) and alpha-beta (Q-band) absorptions. In particular it allows the resolution of resonance Raman spectra of horseradish peroxidase compound I. The bands above 1300 cm-1 can be assigned to porphyrin vibrational modes that are characteristically shifted in frequency due to removal of an electron from the porphyrin ring. The resonance Raman frequency shifts follow normal mode compositions. Relative to resonance Raman spectra of compound II, the v4 frequency (primarily Ca-N) exhibits a 20 cm-1 downshift. The v2, v11, and v37 vibrational frequencies whose mode compositions are primarily porphyrin Cb-Cb, exhibit 10-20 cm-1 upshifts. The v3, v10, and v28 frequencies, whose mode compositions are primarily Ca-Cm, exhibit downshifts. The downshifts for v3 and v10 are small, 3-5 cm-1; however, the downshift for v28 is 14 cm-1. These frequency shifts are consistent with those of previously published resonance Raman studies of model compounds. In contrast to reports from other laboratories, the data presented here for horseradish peroxidase compound I can be attributed unambiguously to resonance Raman scattering from a porphyrin pi-cation radical.     

Organization of the mitochondrial Cob 2 pseudogene in different lines of rice

In the fertile rice line IR 36 there are two copies of the apocytochrome b (cob) gene: a functional copy, cob 1, and a pseudogene, cob 2 (Kaleikau et al. 1992). In a survey of diverse rice lines, we found that cob 2 was absent in the wild abortive(WA)-type cytoplasmic male-sterile cytoplasm, but was present in the fertile lines. While cob 1 was conserved among all the lines, fertile and sterile, the cob 2 region was different in the fertile lines tested. The 5′ regions of most cob 2 loci were similar to cob 1 (about 4 kb of the flanking region and most of the coding region), but the 3′ region varied among different fertile lines. The point of divergence, the break-point, from the cob 1 sequence was conserved in all the cob 2 regions tested. In all the cob 2 regions, this break-point seems to be linked to the variable region of cob 2 through a conserved 192-bp segment, which is not a part of cob 1. It is proposed that the cob 2 regions could have been produced by recombination or insertion events involving cob 1 and the 192-bp segment which is present at different locations in the mitochondrial genomes of the various rice lines.     

Purification and properties of glutamine synthetase from Nocardia asteroides

Glutamine synthetase (GS, EC 6.3.1.2) from Nocardia asteroides was purified to homogeneity by ammonium sulfate precipitation, Sephadex G-150, and DEAE-Sepharose chromatography. The native molecular weight of the purified enzyme was determined to be 720 kDa. SDS-PAGE analysis of the purified preparation revealed a single band corresponding to 59 kDa, indicating the possible presence of 12 identical subunits. The divalent cations Mn^2- and Mg²⁺ were found to be essential for optimal transferase and biosynthetic activity, respectively. The optimal pH and temperature for both activities of the enzyme were found to be 7.2 and 50°C. Amino acids such as l-alanine, glycine, and aspartate inhibited the GS activity. The K _m values for the substrates of the biosynthetic reaction ATP, glutamate, and ammonium chloride were found to be 400 m, 7.7mm, and 200 m, respectively. Addition of ammonium chloride to the nitrogen-limited culture resulted in a decrease of GS transferase and biosynthetic activities. Phosphodiesterase treatment of the extract from ammonia-shocked cultures showed an increase in GS transferase activity. The results indicate the possible regulation of GS by covalent modification.     

Effects of electroconductive heat treatment and electrical pretreatment on thermal death kinetics of selected microorganisms

Suspensions of yeast cell (zygo Saccharomyces bailii) in a phosphate buffer solution were subjected to conventional (hot water) and ohmic (electric current) heating under identical temperature histories. Experiments were also conducted with cells of Escherichia coli to compare the lethal effect of combination of sublethal electrical preteatment and conventional heating with conventional heating. The kinetic parameters (D,Z,K and E(a)) were determined for both organisms during different treatments. There was no significant difference in the death rate of yeast cells during conventional and ohmic heating at the voltage range used in this study. Results of electrical pretreatment and conventional heating on E. coli indicated differences under certain conditions when compared with pure conventional heating. Thus it is concluded that microbial death during ohmic heating was due primarily to thermal effects with no significant effect of electric current per se. Sublethal electrical pretreatment appears to offer potential for increased bacterial inactivation in certain cases.     

Waste paper derived three-dimensional carbon aerogel integrated with ceria/nitrogen-doped reduced graphene oxide as freestanding anode for high performance and durable microbial fuel cells

Bioprocess and Biosystems Engineering - Despite the green energy generation with low cost compared to conventional fuel cells, microbial fuel cells (MFCs) still suffer with anode related...     

Micro‐dose placement of phosphorus induces deep rooting of upland rice

Plant and Soil - Upland rice production is often constrained by phosphorus deficiency (P) and drought events. Methods are needed to maximize P use efficiency, while promoting deep root development...     

On the macro-micro-morphology of organs of host invasion in hemiparasite Helicanthes elasticus (Desv.) Danser

Loranthaceae family includes hemiparasitic members which are seen invading a wide range of commercial crops. Helicanthes elasticus (Desv.) Danser is very common on mango trees. Though parasitic in nature, this mistletoe is also medicinally important as fetoprotective, against vesicular calculi and kidney infections. This study is an attempt to document macro-microscopical features of parasitic root, fruit and host-mistletoe tissue interaction in the haustorium of H. elasticus growing on mango stems. Collection, preservation, sectioning, staining and photomicrography of the root, fruit and host-mistletoe union were done as per standard methodologies of anatomical studies. Though there is resemblance to the normal roots in morphology as well as anatomy, the microscopic finding of large number of branched stone cells in the roots is interesting. The morpho-anatomical features recorded would help in understanding the infection biology of this mistletoe. The eradication during the earlier stages of its establishment from seed or from the root creeping over the surface of the host can help in controlling this parasite infection on commercially important host plants.     

Synthesis of Zidovudine Derivatives with Anti-HIV-1 and Antibacterial Activities

Twelve novel zidovudine derivatives were prepared by modifying 5 ′-hydroxyl group of sugar moiety (1–8) and 5-methyl group of thymidine nucleus (9–12) and characterized spectrally. The compounds were evaluated for anti-HIV-1, antitubercular and antibacterial activities. Compound (3-azido-tetrahydro-5- (3,4-dihydro-5-methyl-2,4-dioxopyrimidin- 1 (2H)-yl) furan-2-yl)methyl 7- (4- (2-phenylacetoyloxy) -3,5- dimethylpiperazin-1-yl) -5- (2-phenylacetoyloxyamino) -1-cyclopropyl-6,8-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate (5) was found to be the most potent anti-HIV-1 agent with EC₅₀ of 0.0012 μM against HIV-1_IIIB and CC₅₀ of 34.05 μM against MT-4 with selectivity index of 28,375. Compound 5 inhibited Mycobacterium tuberculosis with MIC of 1.72 μM and inhibited four pathogenic bacteria with MIC of less than 1 μM.     

Density functional theory investigation of cocaine water complexes

Twenty cocaine–water complexes were studied using density functional theory (DFT) B3LYP/6-311++G** level to understand their geometries, energies, vibrational frequencies, charge transfer and topological parameters. Among the 20 complexes, 12 are neutral and eight are protonated in the cocaine-water complexes. Based on the interaction energy, the protonated complexes are more stable than the neutral complexes. In both complexes, the most stable structure involves the hydrogen bond with water at nitrogen atom in the tropane ring and C?=?O groups in methyl ester. Carbonyl groups in benzoyl and methyl ester is the most reactive site in both forms and it is responsible for the stability order. The calculated topological results show that the interactions involved in the hydrogen bond are electrostatic dominant. Natural bond orbital (NBO) analysis confirms the presence of hydrogen bond and it supports the stability order. Atoms in molecules (AIM) and NBO analysis confirms the C-H?·?·?·?O hydrogen bonds formed between the cocaine-water complexes are blue shifted in nature.