Limitations of the32P isotope injection technique for the study of the root systems of wheat,mung and cowpeas

Summary The³²P isotope injection technique developed by earlier investigators in graminea has been extensively tested, under irrigated agriculture, using three promising varieties of wheat Pusa Lerma (a single gene dwarf) Sharbati Sonora (a double gene dwarf) and a triple gene dwarf 1634. Field experiments supported by pot experiments using both sand and soil cultures gave identical results.Unlike the wheats with a succulant stem the legumes are fibrous and do not permit injection in the stem. The technique was, therefore, modified and the injection had to be given on the leaf stem instead of the plant stem.While equilibrium in wheat was obtained five days after injection both in pot and field experiments mung behaves in a different manner. In the pot experiments the equilibrium could not be attained till the 12th day while in the field experiments it was attained even on the first day after injection. Mung has a thick tap root surrounded by fine secondary roots. The activity was observed to move very fast in the thick tap root even on the first day while the thin secondary roots showed resistance and attained equilibrium on the 3rd day.The anomaly observed in the pot and field experiments was attributed partly to the differential root growth under the two environments studied and to some extent on the probable loss of fine roots in the collection on the field. However, the plants grown both in pots as well as on the field attained equilibrium on the 12th day. In the case of cowpeas the equilibrium was attained on the 8th day.The period required for attaining uniform distribution of activity thus seems to be a function of the morphology of the plant, the pattern of the root system and the injection technique adopted. As this is a pre-requisite for the quantitative estimation of the roots care has to be taken in perfecting the technique.Part of the thesis for which Ph.D. degree was awarded to K. Vijayalakshmi by the Indian Agricultural Research Institute, New Delhi.Dry Land Agriculture Centre, Hyderabad.Nuclear Research Laboratory, at present International Atomic Energy Agency Expert, Mymensingh, Bangladesh.     

Zooplankton composition and diversity in western Bay of Bengal

The biomass of zooplankton ranged from 1 – 90 ml/100 m³in the western Bay of Bengal from off Sri Lanka to south ofCalcutta in June 1978. The coastal belt between Madras and Visakhapatnamwhere upwdling is known to occur during the season showed higherstanding stock. Copepoda formed the dominant group followedby Decapod a and Chaetognatha. Species composition of variousgroups and their distribution is discussed. A general inverserelationship between biomass and species diversity was the trend.Diversity was higher in the oceanic realm.     

Role of metal ions in triazine dye affinity chromatography: The metal mediated interaction of triazine dyes with firefly luciferase

Low concentrations of metals of the first row transition series, Zn²⁺, Co²⁺, Mn²⁺, Ni²⁺, Cu²⁺ and Fe²⁺, and to a lesser extent the group IIa ions, particularly Mg²⁺, influenced the interaction of firefly luciferase [Photinus luciferin:oxygen 4-oxidoreductase (decarboxylating, ATP-hydrolysing), EC 1.13.12.7] with a number of triazine dyes. For example Cu²⁺ promoted the binding of luciferase to Cibacron Brilliant Blue (BR-II) and Cibacron Blue F3GA a dichloro and monochloro triazine dye, respectively. On the other hand Zn²⁺ prevented dye inactivation and even enhanced the enzyme activity. Specificity was observed in the interference of different metals interacting with different dye-protein. This is made use of in triazine dye affinity chromatography.     

Production of bioactive metabolites by Nocardia levis MK-VL_113

Aims: To isolate and identify the bioactive compounds produced by Nocardia levis MK‐VL_113. Methods and Results: Cultural characteristics of Noc. levis isolated from laterite soils of Guntur region were recorded on International Streptomyces Project media. Morphological studies of the strain through scanning electron microscopy revealed the clear pattern of its hyphal fragmentation into rod‐shaped bacilli. Chemical examination of the secondary metabolites of the strain grown on sucrose–tryptone broth led to the isolation of three fractions active against Bacillus cereus. Further analysis of second fraction resulted in the isolation of two active subfractions. Two different phthalate esters, namely, bis‐(2‐ethylhexyl) phthalate and bis‐(5‐ethylheptyl) phthalate, were purified from the first active subfraction, and the structural elucidation of these compounds was confirmed on the basis of FT‐IR, mass and NMR spectroscopy. The partially purified second subfraction subjected to Gas Chromatography–Mass spectroscopy contained nine components: decanedioic acid; 2,6‐piperdione monooxime; 1‐eicosanol; beta‐1‐arabinopyranoside, methyl; cyclopentaneundecanoic acid; hexadecanoic acid; silane, trichloro eicosyl; 1‐hexacosanol; and 1,2‐dodecanediol. The antimicrobial activity of the bioactive compounds produced by Noc. levis was expressed in terms of minimum inhibitory concentration. Conclusions: The present study clearly revealed that the metabolites of Noc. levis act as bioactive compounds against Gram‐positive and Gram‐negative bacteria, yeast and filamentous fungi. It also supports the idea that there are a number of rare actinomycetes remained to be explored for new bioactive compounds. Significance and Impact of the Study: Metabolites of Noc. levis exhibited antibacterial and antifungal activities. This is the first report of bis‐(5‐ethylheptyl) phthalate as well as the nine partially purified compounds from actinomycetes. In addition, this is also the first report of bis‐(2‐ethylhexyl) phthalate from the genus Nocardia.     

Identifying functional metabolic shifts in heart failure with the integration of omics data and a heart-specific,genome-scale model

1. Download : Download high-res image (198KB)
2. Download : Download full-size image