Effects of NaCl and iso-osmotic PEG stress on growth,osmolytes accumulation and antioxidant defense in cultured sugarcane cells

In order to discriminate between the ionic and osmotic components of salt stress, sugarcane (Saccharum officinarum L. cv. Co 86032) calli were cultured on media containing NaCl or polyethylene glycol (PEG) 8000 that exerted the same osmotic pressure (−0.7 MPa). PEG stress exposure for 15 days led to significant growth reduction and loss in water content than salt stressed and control tissues. Osmotic adjustment (OA) was observed in callus tissues grown on salt, but was not evident in callus grown on PEG. Oxidative damage to membranes, estimated in terms of accumulation of thiobarbituric acid reactive substances-TBARS and electrolytic leakage was significantly higher in both the stressed calli than the control however, the extent of damage was more in the PEG stressed calli. The stressed callus tissues showed inhibition of ascorbate peroxidase activity, while catalase activity was increased. These results indicate sensitivity of cells to PEG-mediated stress than salt stress and differences in their OA to these two stress conditions. The sensitivity to the osmotic stress indicate that expression of the stress tolerance response requires the coordinated action of different tissues in a plant and hence was not expressed at the cellular level.     

Management of Evolving Map Data: Data Structures and Algorithms Based on the Framework Map

A consensus framework map of a chromosome is the single most useful map of the chromosome, because of the amount of information it holds as well as the quality of the supporting data backing the putative order of its objects. We describe data structures and algorithms to assist in framework map maintenance and to answer queries about order and distance on genomic objects. We show how these algorithms are efficiently implemented in a client-server relational database. We believe that our data structures are particularly suitable for databases to support collaborative mapping efforts that use heterogeneous methodologies. We summarize two applications that use these algorithms: CHROMINFO, a database specifically designed for framework map maintenance; and the shared client-server database for the chromosome 12 genome center.     

Coimmobilization of D-amino acid oxidase and catalase by entrapment ofTrigonopsis variabilis in radiation polymerised Polyacrylamide beads

Trigonopsis variabilis induced for D-amino acid oxidase and catalase was immobilized by entrapment in Polyacrylamide beads obtained by radiation polymerisation. Permeabilization of the cells was found to be essential for optimal activity of the enzymes in free cells. However, the process of entrapment itself was found to eliminate the permeability barrier of cells immobilized in Polyacrylamide. The two enzymes exhibited a differential response on Polyacrylamide entrapment. Thus, D-amino acid oxidase activity was stabilized to heat inactivation whereas catalase in the same cells showed a destabilization on entrapment in Polyacrylamide. The coimmobilized enzyme preparation showed an operational half life of 7–9 days after which the D-amino acid oxidase activity remained stable at a value 35–40% of that of the initial activity for a study period of 3 weeks. Coimmobilization of MnO₂ was not effective in enhancing the operational life of the enzyme preparation.     

A rapid method for the purification of D-amino acid oxidase of Trigonopsis variabilis by hydrophobic chromatography

Summary A relatively simple method has been described for the rapid purification of D-amino acid oxidase from Trigonopsis variabilis by hydrophobic chromatography on Phenyl-Sepharose CL-4B and negative adsorption on DEAE-cellulose. The purified enzyme had a specific activity of 22–24 units at 25°C and exhibited three bands on enzymatic staining.     

The isolation and immunolocalization of iron-binding compounds produced by Gloeophyllum trabeum

Summary Low molecular weight iron-binding compounds are produced by the brown-rot fungus Gloeophyllum trabeum. These chelators may function in scavenging transition metals for fungal metabolism and extracellular enzyme production. Because of the low molecular mass of the chelate-metal complex (below 1000 Da), and the oxidizing potential of the bound transition metals, certain chelating compounds could also play a role in the early stages of cellulose depolymerization by brown-rot fungi. High-affinity iron-binding compounds were isolated and partially purified from both liquid cultures of the brown-rot Gloeophyllum trabeum and from infected wood. Chelating compounds purified by thin-layer chromatography were used to prepare specific antibodies. These antibodies were shown to detect the chelator in infected wood and liquid fungal cultures by enzyme-linked immunosorbent assay and could be used in immunotransmission electron microscopy to visualize the high-affinity iron-binding compounds in situ. Elucidating the physiological roles of fungal chelate-metal complexes and determining their function in lignocellulose depolymerization will help us to better understand the mechanism of wood biodegradation.Publication no. 1549 Maine Agricultural Experiment Station Offprint requests to: J. Jellison     

Possible implications of reciprocity between ethylene and aflatoxin biogenesis in Aspergillus flavus and Aspergillus parasiticus.

Aspergillus flavus and Aspergillus parasiticus produced ethylene during early growth. However, the onset of toxin biosynthesis was marked by the absence of ethylene evolution. 2-Chloroethyl phosphonic acid, an ethylene-generating compound, inhibited aflatoxin biosynthesis in vivo. The reciprocal relationship between the production of aflatoxin and ethylene by the organism may indicate the involvement of the latter in the regulation of aflatoxin biogenesis.     

Hydrolysis of milk lactose by immobilized beta-galactosidase-hen egg white powder

Immobilized beta-galactosidase was obtained by crosslinking the enzyme with hen egg white using 2% glutaraldehyde. The gel obtained could be lyophilized to give a dry enzyme powder. The pH optimum of both the soluble and immobilized enzyme was found to be 6.8. The immobilized enzyme showed a higher K(m) for the substrates. The extent of enzyme inhibition by galactose was reduced upon immobilization. The stability towards inactivation by heat, urea, gamma irradiation, and protease treatment were enhanced. The bound enzyme as tested in a batch reactor could be used repeatedly for the hydrolysis of milk lactose. The possible application of this system for small-scale domestic use has been suggested.     

Immobilization of fumarase by entrapment of rat liver mitochondria in polyacrylamide gel using gamma rays

A stable immobilized preparation of fumarase (EC 4.2.1.2) was obtained by entrapment of rat liver mitochondria in acrylamide polymerized by using gamma irradiation (100 kR). The enhanced stability and the efficiency of the entrapped enzyme have shown potential for repeated use for the production of L-malic acid from fumaric acid. The possible formation of succinic acid in the system could be controlled by incorporating malonate along with detergents such as sodium deoxycholate or sodium dodecylsulfate in the reactor system.     

Chemodiversity and α-Glucosidase Activity of Eucalyptus Species from Northwestern Himalaya,India

The aim of current work was to determine essential oils (EOs) composition from three Eucalyptus species, including E. citriodora, E. camaldulensis and E. globulus and assess their α-glucosidase inhibitory activity. The EOs were collected using the hydrodistillation technique and characterized by GC/MS, GC-FID and NMR. The isolated EOs from leaves parts of Eucalyptus species varied from 0.56 to 1.0 % on fresh weight basis. The content of the EOs was distinct according to the species. The most abundant metabolites were identified as citronellal (0–83.0 %), 1,8-cineole (0.2–44.8 %), spathulenol (0.4–16.1 %) α-pinene (0.4–15.9 %), p-cymene (3.7–11.9 %), citronellol (0–8.6 %), β-eudesmol (5.3–8.6 %) and β-pinene (0–7.1 %). The EOs obtained from targeted samples exhibited strong α-glucosidase inhibitory activity. These results are encouraging and underline that the EOs of Eucalyptus species may be a promising alternative source of natural antidiabetic.     

Kraft black liquor for improving the productivity of Spirulina biomass

Summary Mass cultivation of Spirulina for commercial application suffers from poor productivity when measured against laboratory results or theoretical projections. Wider applications of algal products require that this gap be reduced. Addition of eucalyptus kraft black liquor at a maximum of 0.1% to Spirulina cultures enhanced biomass productivity by at least 40%. The factors enhancing Spirulina biomass productivity were insoluble at low pH, of low molecular mass and stable to high temperature. Single addition of kraft black liquor in outdoor continuous cultures afforded sustained enhancement in biomass productivity for at least eight weeks.