Elicitation of anthocyanin production in cell cultures of carrot (Daucus carota L) by using elicitors and abiotic stress

Summary A cell line of carrot (Daucus carota L) which produces anthocyanin was subjected to various elicitors and abiotic stresses: The elicitors tested were culture filtrates (CF) and cell extracts (CE) of certain bacteria and yeasts. The abiotic stresses were salts of certain metal ions. The production increase obtained with cell extracts of Bacillus cereus. Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were 49, 72, 45 and 41% respectively over the control. Maximum elicitation was obtained with elicitor derived from cell extract of the yeast Rhodotorula rubra where it enhanced anthocyanin production by two fold. The abiotic stress agents Ca, Mn, Zn, Co, Fe & V enhanced anthocyanin production. Of all the metal ions tested Ca was the most effective. The elicitation process was governed by the type and level of elicitor.     

Molecular Mechanism of Nramp-Family Transition Metal Transport

The Natural resistance-associated macrophage protein (Nramp) family of transition metal transporters enables uptake and trafficking of essential micronutrients that all organisms must acquire to survive. Two decades after Nramps were identified as proton-driven, voltage-dependent secondary transporters, multiple Nramp crystal structures have begun to illustrate the fine details of the transport process and provide a new framework for understanding a wealth of preexisting biochemical data. Here we review the relevant literature pertaining to Nramps’ biological roles and especially their conserved molecular mechanism, including our updated understanding of conformational change, metal binding and transport, substrate selectivity, proton transport, proton-metal coupling, and voltage dependence. We ultimately describe how the Nramp family has adapted the LeuT fold common to many secondary transporters to provide selective transition-metal transport with a mechanism that deviates from the canonical model of symport.     

Nature and role of plasmids in Azotobacter chroococcum

Summary Heavy metal, antibiotic resistance and hydrocarbon utilization properties were studied inAzotobactor chroococcum to investigate the nature and role of plasmids in different soil isolates. There is wide prevalence of heavy metal resistance, antibiotic resistance and utilization of hydrocarbons; the heavy metal resistance property seems to be conferred by plasmids.     

Use of wild type and nickel resistantNeurospora crassa for removal of Ni2+ from aqueous medium

Summary A novel nickel resistant, hyperaccumulatingN.crassa nir-2 mutant, isolated by us, sequestered 90% of Ni²⁺ from medium with 120 mg/l Ni²⁺. The parent wild strain showed comparable efficiency only at much lower concentrations (<10mg/l). The initial rapid rate and efficiency of Ni²⁺ removal could be maintained beyond 2 h by fresh addition of mycelial biomass. The results have been discussed from the stand point of the utility of metal resistant fungi in the control of environmental pollution.     

Production of mold lactase

A process for production of mold lactase was developed. Tests were carried out in pilot and industrial scale with an Aspergillus niger strain selected after screening a number of molds.A computer coupled autoanalyzer system was used for monitoring enzyme formation in the pilot fermentor. Lactase production was investigated using different pH- and temperature-profiles. A. niger lactase has an acid pH optimum, a high temperature optimum and good stability. It does not require any metal ions. It is suitable for immobilization for hydrolysis of lactose in acid whey.Three-fold enhancement of lactase production was obtained by mutagenizing A. niger using NTG as mutagenic agent.The lactases produced by the mutants have the same pH and temperature optima and stability but the growth properties of the mutants were different from those of the original strain.Sufficient specific activity of the enzyme preparation for immobilization was obtained by purifying the enzyme by selective adsorption on Na-Ca-silicate.     

Rapid screening of peptides for heavy metal binding

Summary A simple method that allows testing and characterisation of cadmium binding motifs by large set of immobilized peptides was developed. Hepta- and octapeptides containing cysteine and histidine residues were synthesized on cotton carrier. They were tested for cadmium binding. pH values of half metal dissociation were measured. Test for Cd binding was based on its precipitation with ferrous dipyridyl iodide. Subsequent dissolving of precipitate provided semiquantitative data on relative amount of Cd bound. Observed data for particular peptides corresponded with prediction.Abbreviations Boc tercial butyloxycarboyl - Fmoc fluorenylmethyloxycarboyl - tBu tercial butyl - DMF N,N-dimethylformamide - DCM dichlormethane - Me methyl     

Improved Parameters for Generating Partial Charges: Correlation with Observed Dipole Moments

The Universal Force Field was initially combined with the Charge Equilibrium Scheme in the molecular mechanics program AMMP in order to generate partial charges for protein atoms. A new parameter set with improved generation of partial charges has been derived in order to analyse a wider range of atoms and compounds. The electrostatic parameters were modified to achieve better correlation with experimental dipole moments for a training set of 160 compounds, which included alkali metal halogenides, saturated and unsaturated hydrocarbons, alcohols, ethers, amines, thiols, sulphides, oxo compounds, aromatic and heteroaromatic molecules. The correlation coefficient for the calculated and experimental dipole moments was improved from 0.57 to 0.98. The new parameters were tested for another 149 compounds and the correlation coefficient increased from 0.48 to 0.85. The newly generated Modified Parameter Set for AMMP (MOPSA) improves the predictive power of the program, especially in the area of the macromolecular modelling and drug design, where the nonbonded energies play a crucial role.Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s008940050114     

Selection of preculture conditions for solid state fermentation of sugar beet pulp

Summary For the protein upgrading of sugar-beet pulp in solid state fermentation byTrichoderma reesei andFusarium oxysporum, serveral conditions were studied to prepare an economical preculture for large scale process. The best performance was shown by a preculture obtained in 24 h from 1.5 % molasses solution at pH 4.5–5.0 with 1.0 % milled beet pulp.     

Fermentation of starch to ethanol by a complementary mixture of an amylolytic yeast andSaccharomyces cerevisiae

Summary Synergistic coculture of an amylolytic yeast (Saccharomycopsis fibuligera) andS. cerevisiae, a non-amylolytic yeast, fermented unhydrolyzed starch to ethanol with conversion efficiencies over 90% of the theoretical maximum. Fermentation was optimal between pH 5.0 to 6.0. Using a starch concentration of 10% (w/v) and a 5% (v/v) inoculum ofS. fibuligera, increasingS. cerevisiae inoculum from 4% to 12% (w/v) resulted in 35–40% (w/v) increase in ethanol yields. Anaerobic or limited aerobic incubation almost doubled ethanol yields.     

Intergeneric protoplast fusion between Brassica carinata and Camelina sativa

Camelina sativa is a wild crucifer that is reported to be resistant to Alternaria blight. Polyethylene glycol mediated fusion was attempted between protoplasts from etiolated hypocotyls of Brassica carinata and mesophyll protoplasts of Camelina sativa. The mean frequency of heterokaryons was 6.8%. Three hybrid shoots were regenerated, each from a single fusionderived callus. These shoots failed to produce roots capable of withstanding transplantation. Confirmation of hybridity was obtained from the morphology of in vitro produced leaves, somatic chromosome number in leaf tips, and restriction fragment length polymorphism for a nuclear rDNA probe. Analysis for organelle constitution using RFLPs indicated that the hybrid contained chrloroplasts derived from the wild species and mitochondria from the cultivated Brassica species.Abbreviations 2,4-D 2,4-dichlorophenoxy-acetic acid - IAA Indole-3-acetic acid - NAA -Naphthaleneacetic acid - IBA Indole-3-butyric acid - GA₃ gibberellic acid - BAP 6-Benzylaminopurine - MS Murashige and Skoog (1962) basal medium     

Non-polluting wood and pulp delignification: Biomimetic ligninase system

Summary We report the delignification ofPinus radiata D Don,Eucalyptus globulus andEucalyptus grandis woods (formic acid treated and untreated) by 2 h treatment with a hemin/hydrogen peroxide system. The untreated chips and sawdust ofE. globulus were 30% and 50% delignified respectively. No significant effects were found forP. radiata sawdust;P. radiata treated chips (organosolv pulp) did not show any further delignification upon hemin/peroxide action, 25% delignification was achieved in untreated chips. In the case ofE. grandis untreated wood the delignification was better in sawdust than in chips, but in smaller percentage than in the otherEucalyptus species. This relation is maintained in substrates, treated with formic acid or untreated. The delignification of chips in both species ofEucalyptus was improved when they were pre-treated with formic acid. The loss of lignin in theE. grandis andE. globulus sawdust (pre-treated with formic acid) was 79% and 75% respectively.     

Grape pomace: A novel substrate for microbial production of citric acid

Summary Grape pomace was used as substrate for microbial production of citric acid. Of the five cultures examined,Aspergillus niger NRRL 567 was found to produce the greatest amount of citric acid from grape pomace in the presence of methanol at a concentration of 3% (vol/wt). The yield was 60% based on the amount of fermentable sugar consumed.     

Production and conversion of chitosan with cultures of Mucor rouxii or Phycomyces blakesleeanus

Summary Highly deacetylated chitosan was accumulated in the mycelia ofMucor rouxii orPhycomyces blakesleeanus. These cultures also effected the deacetylation of the chitin ofAspergillus niger mycelium into chitosan. After 96 hours of incubation with these cultures the degree of acetylation of commercial crab shell chitosan was reduced from 25.0% to values between 4.3 and 8.6%. The potential exists for the production of chitosans with tailored physico-chemical properties from waste chitin.     

Production of fructosyl transferase fromAureobasidium pullulans

Summary Conditions for the production of intracellular fructosyl transferase fromA. pullulans were investigated. Sucrose was an excellent carbon source, and there was a tendency for the enzyme production to be increased as sucrose concentration was increased. Both 0.5% phosphate and 2% sodium nitrate had positive effects on enzyme production. It was possible to increase the intracellular enzyme production up to 140% by increasing the concentration of magnesium sulfate from 0.05 % to 0.2%.     

Apple pomace: A potential substrate for citric acid production by Aspergillus niger

Summary Apple pomace was used as a fsubstrate for citric acid production by five strains of Aspergillus niger. A. niger NRRL 567 produced the greatest amount of citric acid from apple pomace in the presence of 4% methanol. The yield was 88% based on the amount of sugar consumed.     

Selective production of phenylalanine from phenylpyruvate using growing cells ofCorynebacterium glutamicum

Summary Phenylalanine was produced from phenylpyruvate by growing cells of a mutant strain ofCorynebacterium glutamicum over-producing valine. A defined medium was used to minimize the accumulation of valine. The maximum phenylalanine concentration achieved was 44.5 mM (7.5 g/l) with a phenylpyruvate molar conversion of 75%.     

Thermostable tryptophan synthase ofBacillus stearothermophilus expressed inEscherichia coli

Summary The tryptophan synthase genes,trpA andtrpB, from a moderate thermophile,Bacillus stearothermophilus IFO13737, were expressed efficiently inEscherichia coli. The recombinant tryptophan synthase amounted to 22% of the soluble cellular protein, and was purified to homogeneity by three steps. The enzyme is more thermostable thanE.coli tryptophan synthase, especially the subunit. The enzyme is also more resistant to sodium dodecylsulfate and methanol thanE.coli enzyme.     

Correlation between flow cytometric determination of nuclear DNA content and chromosome number in somatic hybrids within Brassicaceae

Summary Fourty-one somatic hybrids from two species combinations, Brassica oleracea + B. campestris and B. napus + Eruca sativa, were analysed for chromosome number and nuclear DNA content. The DNA content was measured in a flow cytometer using two internal standards as references and when related to the chromosome number a correlation of 0.91 was found. The chromosome number of the hybrids could be determined with an accuracy of ±10% by using flow cytometry, and the smallest statistically significant difference in DNA content between two individuals was 0.23 pg DNA/cell.     

Simultaneous saccharification and protein enrichment fermentation of sugar beet pulp

Summary A product with 40 % protein content was obtained from sugar beet pulp (1.25–2.0 mm) in 48 h one stage (simultaneous) saccharification/fermentation process under optimized conditions using a specific enzyme mixture andCandida tropicalis strain, also saving about 40 % enzymes in comparison to a 2-stage process.     

Plant regeneration from cultured cell-derived protoplasts of Pelargonium aridum,P. x hortorum and P. peltatum

Cultured protoplasts from cell suspensions of Pelargonium aridum, P.x hortorum and P. peltatum divided and formed callus. On agar-solidified regenerative medium, such protoplast-derived calli (p-calli) underwent plant regeneration at frequencies approaching 100% for P. aridum and 10% for P.x hortorum. Under similar conditions shoot primordia arose in 5% of P. peltatum p-calli, but these never developed into normal shoots. However, following a liquid-shake culture regime, whole plants were induced in 20% of P. peltatum p-calli. This approach also improved regeneration of P.x hortorum to 60%.Abbreviations NAA napthaleneacetic acid - 6-BAP 6-benzylaminopurine