Biodegradation of dimethylterephthalate by Comamonas acidovorans D-4.

Comamonas acidovorans D-4, capable of utilizing dimethylterephthalate (DMT) as the sole carbon source, was isolated from the activated sludge of petrochemical wastewater treatment plant. Almost complete utilization of as high as 0.5% (w/v) DMT was observed in 72 hr. Growth kinetics followed a parallel relation between the growth, DMT utilization and cell associated esterase activity. A cell free broth of DMT grown cells showed an extracellular esterase activity. During the DMT degradation an extracellular accumulation of terephthalic acid was found. Although, C. acidovorans grew on a number of phthalate esters and phthalic acids as the sole carbon source, growth was significantly high on phthalic acids. The potential of this organism in petrochemical pollution abatement is discussed.

Microbial production of surfactants and their commercial potential.

Many microorganisms, especially bacteria, produce biosurfactants when grown on water-immiscible substrates. Biosurfactants are more effective, selective, environmentally friendly, and stable than many synthetic surfactants. Most common biosurfactants are glycolipids in which carbohydrates are attached to a long-chain aliphatic acid, while others, like lipopeptides, lipoproteins, and heteropolysaccharides, are more complex. Rapid and reliable methods for screening and selection of biosurfactant-producing microorganisms and evaluation of their activity have been developed. Genes involved in rhamnolipid synthesis (rhlAB) and regulation (rhlI and rhlR) in Pseudomonas aeruginosa are characterized, and expression of rhlAB in heterologous hosts is discussed. Genes for surfactin production (sfp, srfA, and comA) in Bacillus spp. are also characterized. Fermentative production of biosurfactants depends primarily on the microbial strain, source of carbon and nitrogen, pH, temperature, and concentration of oxygen and metal ions. Addition of water-immiscible substrates to media and nitrogen and iron limitations in the media result in an overproduction of some biosurfactants. Other important advances are the use of water-soluble substrates and agroindustrial wastes for production, development of continuous recovery processes, and production through biotransformation. Commercialization of biosurfactants in the cosmetic, food, health care, pulp- and paper-processing, coal, ceramic, and metal industries has been proposed. However, the most promising applications are cleaning of oil-contaminated tankers, oil spill management, transportation of heavy crude oil, enhanced oil recovery, recovery of crude oil from sludge, and bioremediation of sites contaminated with hydrocarbons, heavy metals, and other pollutants. Perspectives for future research and applications are also discussed.

Brown tumor of the hard palate in secondary hyperparathyroidism.

Jaw bones are rarely involved in secondary hyperparathyroidism. We report a case of 13 year old girl who presented with progressive chronic renal failure and secondary hyperparathyroidism. Five months after beginning of hemodialysis, a large brown tumor developed on the hard palate, extending to the maxilla causing difficulty in swallowing and breathing. She died of massive intestinal hemorrhage five months after excision of the mass.

Biodegradation of slop oil from a petrochemical industry and bioreclamation of slop oil contaminated soil.

Slop oil, i.e. waste oil from a petrochemical complex, contains at least 240 hydrocarbon components, of which 54% are from C5 to C11 and the rest from C12 to C23. Of 22 isolated bacterial cultures that were able to degrade slop oil, seven could each degrade about 40% of the slop oil, and a mixture of all seven could degrade ≤50% in liquid medium. Bioaugmentation of soil contaminated with slop oil with the mixed bacterial culture gave up to 70% degradation of slop oil after 30 days. This compares with 40% degradation without bioaugmentation. Bioaugmentation led to a significant increase in counts of bacteria able to degrade slop oil. Wheat sown on bioaugmented soil germinated and grew better than on non-augmented soil and led to increased degradation of slop oil (up to 80%). This indicates the potential of mixed culture for bioremediation.

Fine needle aspiration cytology (FNAC) in the evaluation of acute renal allograft rejection.

310 Fine needle aspirations biopsies (FNAB) were performed in sixty-five live related renal donor transplant recipients in a prospective study over 2 years. 82.8% of FNAB were adequate for opinion and there were no complications after the procedure. Methodology used and interpretation of FNACs was as described by Von Willebrand and Hayry. The procedure of FNAC had a sensitivity of 83.3%, specificity of 98.3% and accuracy of 96.1%, and statistically significant (p < .001) correlation was noted between FNAC and Needle biopsy. The increment in lymphoblasts, lymphocytes and score above 3 was suggestive of acute cellular rejection. Increment in monocytes and macrophages above 1% in addition to other cells, was suggestive of acute vascular rejection. FNAC was found to be a safe, simple and easy procedure with high specificity and sensitivity.

Hydrocarbon emulsification by Candida tropicalis and Debaryomyces polymorphus.

Potentiality of C. tropicalis and D. polymorphus, to produce surface active compounds (bioemulsifiers/biosurfactants) during shake cultivation on hexadecane and oily waste was studied. Better emulsification activity, specific towards aromatic hydrocarbons, was observed with C. tropicalis culture broth. Emulsification activity of culture broth was quite stable and was unaffected by change in pH and by increasing the concentration of NaCl up to 5%. The activity was marginally affected by heating in boiling water bath for 15 min, but inhibited to the tune of 90% by 0.3% CaCl2. The isolated bioemulsifying factor contained 40, 22 and 17.5% lipid, protein and carbohydrate, respectively.

Genetic analyses of the mannitol permease of Escherichia coli: isolation and characterization of a transport-deficient mutant which retains phosphorylation activity.

Three positive selection procedures were developed for the isolation of plasmid-encoded mutants which were defective in the mannitol enzyme II (IIMtl) of the phosphotransferase system (mtlA mutants). The mutants were characterized with respect to the following properties: (i) fermentation, (ii) transport, (iii) phosphoenolpyruvate(PEP)-dependent phosphorylation, and (iv) mannitol-1-phosphate-dependent transphosphorylation of mannitol. Cell lysis in response to indole acrylic acid, which causes the lethal overexpression of the plasmid-encoded mtlA gene, was also scored. No correlation was noted between residual IIMtl activity in the mutants and sensitivity to the toxic effect of indole acrylic acid. Plasmid-encoded mutants were isolated with (i) total or partial loss of all activities assayed, (ii) nearly normal rates of transphosphorylation but reduced rates of PEP-dependent phosphorylation, (iii) nearly normal rates of PEP-dependent phosphorylation but reduced rates of transphosphorylation, and (iv) total loss of transport activity but substantial retention of both phosphorylation activities in vitro. A mutant of this fourth class was extensively characterized. The mutant IIMtl was shown to be more thermolabile than the wild-type enzyme, it exhibited altered kinetic behavior, and it was shown to arise by a single nucleotide substitution (G-895----A) in the mtlA gene, causing a single amino acyl substitution (Gly-253----Glu) in the permease. The results show that a single amino acyl substitution can abolish transport function without abolishing phosphorylation activity. This work serves to identify a site which is crucial to the transport function of the enzyme.

Possible Involvement of Phage-Like Structures in Antagonism of Cowpea Rhizobia by Rhizobium trifolii.

A reduction in the viability of cowpea rhizobia was observed when Rhizobium trifolii IARI and cowpea Rhizobium strain 3824 were inoculated together in soil. The reduction in number of cowpea rhizobia in soil was found to be associated with the reduction in number of nodules per plant and retardation in plant growth. An antimicrobial substance was isolated from R. trifolii which, on electron microscopic investigation, demonstrated the presence of several phage-like structures.

Effect of melanin on enzymatic hydrolysis of cellulosic waste.

Wood waste powder from Tectona grandis containing melanin was less susceptible to enzymatic hydrolysis than powder without melanin. About a 53% increase in saccharification was noted when melanin was removed. Melanin caused inhibition to all cellulolytic enzymes, but in different degrees. Endo-beta-1,4-glucanase and beta-glucosidase were markedly inhibited when melanin was preincubated with enzyme, while exo-beta-1,4-glucanase was severely inhibited when melanin was preincubated with substrate. The latter was found to be dependent on the contact time. The activities of endo-beta-1,4-glucanase and beta-glucosidase were noncompetitively inhibited by melanin.

Cooperative binding of the sugar substrates and allosteric regulatory protein (enzyme IIIGlc of the phosphotransferase system) to the lactose and melibiose permeases in Escherichia coli and Salmonella typhimurium.

An Escherichia coli strain which overproduces the lactose permease was used to investigate the mechanism of allosteric regulation of this permease and those specific for melibiose, glycerol, and maltose by the phosphoenolpyruvate-sugar phosphotransferase system (PTS). Thio-beta-digalactoside, a high affinity substrate of the lactose permease, released the glycerol and maltose permeases from inhibition by methyl-alpha-d-glucoside. Resumption of glycerol uptake occurred immediately upon addition of the galactoside. The effect was not observed in a strain which lacked or contained normal levels of the lactose permease, but growth of wild-type E. coli in the presence of isopropyl-beta-thiogalactoside plus cyclic AMP resulted in enhanced synthesis of the lactose permease so that galactosides relieved inhibition of glycerol uptake. Thiodigalactoside also relieved the inhibition of glycerol uptake caused by the presence of other PTS substrates such as fructose, mannitol, glucose, 2-deoxyglucose, and 5-thioglucose. Inhibition of adenylate cyclase activity by methyl-alpha-glucoside was also relieved by thiodigalactoside in E. coli T52RT provided that the lactose permease protein was induced to high levels. Cooperative binding of sugar and enzyme III(Glc) to the melibiose permease in Salmonella typhimurium was demonstrated, but no cooperativity was noted with the glycerol and maltose permeases. These results are consistent with a mechanism of PTS-mediated regulation of the lactose and melibiose permeases involving a fixed number of allosteric regulatory proteins (enzyme III(Glc)) which may be titrated by the increased number of substrate-activated permease proteins. This work suggests that the cooperativity in the binding of sugar substrate and enzyme III(Glc) to the permease, demonstrated previously in in vitro experiments, has mechanistic significance in vivo. It substantiates the conclusion that PTS-mediated regulation of non-PTS permease activities involves direct allosteric interaction between the permeases and enzyme III(Glc), the postulated regulatory protein of the PTS.

Effect of biotin on alkaloid production during submerged cultivation of Claviceps sp. strain SD-58.

Addition of biotin to culture medium NL-406 significantly increased alkaloid yield during submerged cultivation of Claviceps sp. strain SD-58. Alkaloid yield was further enhanced by incorporating leucine in biotin-supplemented culture medium. Increased alkaloid production was associated with an increase in the lipid content of cells and in the number of chlamydospores. Biotin deficiency caused a reduction in alkaloid yield and a parallel decrease in lipid content and chlamydospore numbers.

Production of Antimicrobial and Bacteriocin-Like Substances by Rhizobium trifolii.

Rhizobium trifolii strains IARI and Rel-1 produced substances with broad and narrow activity spectra, respectively. Reproducible inhibitory zones of various sizes produced by R. trifolii IARI (2 to 14 mm) and R. trifolii Rel-1 (2 to 6 mm) were detected, depending upon the indicator organism used. The maximum production of these substances by both strains of R. trifolii was observed on l-arabinose agar. A preliminary characterization of the antimicrobial substance produced by strain IARI showed resistance to heat (75 to 80 degrees C for 45 min), trypsin, lysozyme, DNase I, and RNase A. On the other hand, the substance produced by strain Rel-1 showed sensitivity to heat (75 to 80 degrees C for 45 min) and trypsin, but resistance to lysozyme, RNase A, and DNase I.

Alkaloid production by Claviceps sp. SD-58; involvement of phosphatase isozymes.

Simultaneous reduction in alkaloid yield and level of phosphatases by high concentrations of phosphate was observed in Claviceps sp. SD-58. Tryptophan-induced culture showed an increase in alkaloid yield and the level of phosphatases. Phosphate caused repression of both acid phosphatase (isoenzyme I) and alkaline phosphatase (isoenzymes III and V).

A new method for isolation of saprophytic cultures of Claviceps fusiformis from sclerotia.

The proposed method includes primary and secondary treatments. Of the various disinfectants tested, 1-propanol and 1-butanol as a primary treatment and phenol, resorcinol, HgC12 or NaCl as a secondary treatment completely eliminated the contamination hazard. 1-Butanol and phenol were not useful disinfectants since they inhibited the growth of C. fusiformis along with the other contaminants. Primary and secondary treatment of sclerotia with 1-propanol and resorcinol, respectively, produced the maximum of stable cultures. Out of 120 cultures tested, 5 cultures demonstrated an appreciable yield of alkaloids under submerged cultural conditions.