Plant growth activity of guaianolides with C-4 oxygen-containing groups

The plant growth activity of guaianolides with C-4 oxygen-containing functions has been studied. It was found that the presence of an epoxy or an ether link at C-4 enhanced the plant growth activity of the parent compound. The presence of a hydroxyl group at C-4 had no effect.     

DNA changes during sequential leaf senescence of tobacco (Nicotiana tabacum)

Age related DNA changes in tobacco (Nicotiana tabacum) leaf nuclei were investigated by Feulgen cytophotometry, thermal denaturation, renaturation, and DNA-DNA hybridization studies during sequential leaf senescence. Cytophotometric Feulgen-DNA comparison measurements between young and senescing nuclei displayed 18% reduction in Feulgen-DNA values, with a corresponding decrease in nuclear area in senescing nuclei. Hydrolysis kinetics indicated that the loss was not due to compactness of the DNA as the curves for older nuclei were consistently lower than curves generated from younger nuclei. DNA loss in senescing nuclei was associated with a decrease in euchromatin or shift from euchromatin to facultative heterochromatin. Purified DNA from young and senescing leaf nuclei did not display different thermal profiles nor did hydroxylapatite chromatography reassociation curves. DNA-DNA hybridization in free solution from young and senescing leaf DNA performed by a Gilford thermo-programmer system indicated that DNA of senescing tobacco nuclei reassociated more slowly than DNA from young nuclei and the mixture of young and senescing leaf DNA displayed intermediate reassociation values. The study indicates that the DNA changes during senescence involve a complex phenomenon which includes the possibility of small single strand nicks undetectable by thermal denaturation, and a loss of small double strand fragments which were detectable only by precise DNA-DNA free solution reassociation and not by hydroxylapatite chromatography reassociation.     

The general utility of a glycerophosphate-Tris buffered medium

D ouglas , J., D hillon , J. & S mith , S.E. 1984. The general utility of a glycerophosphate-Tris buffered medium. Journal of Applied Bacteriology 56 , 321–326.
An easily prepared medium, originally designed for the cultivation of lactic phages, has been found to have much wider application. Experience in its use over a ten year period with a range of physiologically diverse bacteria, for teaching and research, are summarized and evaluated.     

3NTPT: a newly discovered antifertility agent. V. Ovarian dysfunction in Dysdercus koenigii.

A 4 h exposure to a residual film of 15 mg 1-(3-nitrophenyl)-4,4,6-trimethyl-1H,4H-pyrimidine-2-thiol (3NTPT) dissolved in 5 ml acetone significantly inhibited ovarian growth in Dysdercus koenigii. The ovaries of treated females remained small and the trophocytes, the trophic core, the prefollicular tissue and the oogonia completely degenerated. This was followed by degenerative changes in the follicular epithelium, the interfollicular tissue and the developing oocytes. Resorption of the oocytes reduced the vitellarium to an empty tube. The follicular epithelium of the resorbed oocytes protruded into the lumen, while the interfollicular tissue completely degenerated. By day 7 after treatment, the ovaries were completely dystrophic, and this state was not reversible.     

Monitoring of microbial proteome dynamics using Raman stable isotope probing

Abnormal protein kinetics could be a cause of several diseases associated with essential life processes. An accurate understanding of protein dynamics and turnover is essential for developing diagnostic or therapeutic tools to monitor these changes. Raman spectroscopy in combination with stable isotope probes (SIP) such as carbon-13, and deuterium has been a breakthrough in the qualitative and quantitative study of various metabolites. In this work, we are reporting the utility of Raman-SIP for monitoring dynamic changes in the proteome at the community level. We have used ¹³C-labeled glucose as the only carbon source in the medium and verified its incorporation in the microbial biomass in a time-dependent manner. A visible redshift in the Raman spectral vibrations of major biomolecules such as nucleic acids, phenylalanine, tyrosine, amide I, and amide III were observed. Temporal changes in the intensity of these bands demonstrating the feasibility of protein turnover monitoring were also verified. Kanamycin, a protein synthesis inhibitor was used to assess the feasibility of identifying effects on protein turnover in the cells. Successful application of this work can provide an alternate/adjunct tool for monitoring proteome-level changes in an objective and nondestructive manner.     

Partial Diallel Cross in Multi-environment

Analysis of partial diallel cross repeated over environments is discussed. Formulae are given to estimate the general combining ability effects and their interaction effects with environments. Analysis of variance table along with expected mean squares is given.     

Formation of some monopositive and dipositive carbonium ions in chlorosulphuric acid. Part XV

Tetraphenyl-p-xylene-glycol, tetraphenyl-phthalein and Dipheno(3-10′)thiazinyl are shown to form dipositive carbonium ions, but triphenyl acetic acid, 2-3-5-6 tetramethyl benzoic acid, 2-3-4-5-6 pentamethyl benzoic acid, tert-butyl alcohol, triphenyl carbinol, tri-p-tolyl carbinol, tri-o-tolyl carbinol, tri-p-chlorophenyl carbinol and tri-p-nitrophenyl carbinol form monopositive carbonium ions in chlorosulphuric acid, as revealed by conductometric and u.v. spectral studies. Oxalyl chloride decomposes while ethylene glycol is sulphonated in chlorosulphuric acid. Dichloroethane behaves as a non-electrolyte but dibromomethane disproportionates in this medium.     

DNA CONTENT AND HETEROCHROMATIN VARIATIONS IN VARIOUS TISSUES OF PEANUT (ARACHIS HYPOGAEA)

The average 2C DNA amount for the peanut (Arachis hypogaea L.) genome is 4.21 pg, and 73% of the dormant peanut cotyledon nuclei displayed 8C DNA amounts or higher, as compared to 0 to 4% in root-shoot apices and leaf tissue. Thermal melt profiles and heterochromatin values indicated replication of the whole genome. Cotyledon nuclear DNA declined in the percent of polyploid nuclei as well as DNA amounts within ploidy classes during germination. The presence of high DNA C levels in cotyledons generated during embryogeny is interpreted to increase the protein-synthesizing capacity and subsequently supplies a ready source of nucleosides and phosphates during early embryo growth as a result of DNA degradation. However, the later DNA decline at the onset of cotyledon senescence was age related similarly to leaf senescence. The change in proportion of heterochromatin was related to the metabolic state of the tissue and not to the DNA content, as dormant and senescing nuclei contained a higher proportion of heterochromatin as compared to nuclei from metabolically active tissue such as germinating roots. The shift in heterochromatin is interpreted to be involved in gene expression.