Ester Production by Pseudomonas fragi. II. Factors Influencing Ester Levels in Milk Cultures

Cultures of Pseudomonas fragi were grown at 21 C in sterile homogenized milk and reconstituted skim milk media supplemented with ethyl alcohol. Quantitative determinations of ethyl butyrate and ethyl hexanoate by gas-liquid chromatography showed definite increases in the concentrations of the two esters produced in these media in comparison to media not supplemented with ethyl alcohol. Supplementation with butyric acid in addition to ethyl alcohol generally elevated the ethyl butyrate concentration and usually depressed the cell count slightly. Aeration of any of the media during growth tended to reduce the cell population slightly. A relationship between increase in cell number and increase in concentration of esters during the growth of the culture was observed. Media containing high concentrations of ethyl alcohol plus milk fat or low-molecular-weight fatty acids were conducive to the production of a fruity aroma by P. fragi.     

The role of calcium ions in gravity singal perception and transduction

Ca²⁺ is implicated as a messenger in coupling various environmental stimuli, such as gravity and light, to response. In recent years, it has become evident that Ca²⁺ plays a central role in all three phases of gravitropism – perception, transduction and response. The root cap, which is known to contain high amounts of Ca²⁺ and calmoduin, is the primary site of gravity preeception. The possible role of phosphoinositide turnovr and Ca²⁺ and Ca²⁺ calmodulin-dependent enzymes such as Ca²⁺– ATPase and protein kinases in gravitropsim is discussed. A model is proposed to describe the role of Ca²⁺ in both normal and light-dependnt gravity response in roots.     

Differential response of soybean genotypes to soil pH and manganese application

An experiment was conducted at Tamil Nadu Agricultural University, Coimbatore, India during 1982 wet season (June–July) to study the root activity and rooting pattern of IR-20 rice as influenced by urea insecticide combinations by a³²P absorption technique. The treatments involved a factorial combination of four levels of N (0, 60, 90 and 120 kg N/ha) as urea and three levels of insecticides (no insecticide, carbofuran @ 0.75 kg a.i./ha and phorate @ 1.0 kg a.i./ha). The root activity measured in terms of the amount of³²P absorbed by the plant, increased considerably by the application of urea and insecticides (carbofuran or phorate) as well as due to their interactions. The root activity increased upto 120 kg N ha⁻¹. Carbofuran or phorate application increased root activity and the effect of carbofuran was greater than that of phorate. Nitrogen-insecticide interaction was positive on root activity upto 120 kg N ha⁻¹ and the effect was more marked with carbofuran and N combinations. But the percentage distribution of active roots of rice could not be influenced by levels of N, insecticides or their interactions. About 80 percent of the roots of IR 20 rice forage within 10 cm from the surface. The enhanced root activity due to application of N and insecticides (carbofuran and phorate) increased the uptake of major and micro-nutrients. the phytotonic effects of carbofuran and phorate on rice works by triggering the root activity of the crop.     

Inactivation of clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase by sodium nitrite

Clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase activity was investigated after in vitro or in vivo treatment with sodium nitrite. In vitro treatment of commercially available Clostridium pasteurianum ferredoxin with sodium nitrite inhibited ferredoxin activity. Inhibition of ferredoxin activity increased with increasing levels of sodium nitrite. Ferredoxin was isolated from normal C. pasteurianum and Clostridium botulinum cultures and from cultures incubated with 1,000 micrograms of sodium nitrite per ml for 45 min. The activity of in vivo nitrite-treated ferredoxin was decreased compared with that of control ferredoxin. Pyruvate-ferredoxin oxidoreductase isolated from C. botulinum cultures incubated with 1,000 micrograms of sodium nitrite per ml showed less activity than did control oxidoreductase. It is concluded that the antibotulinal activity of nitrite is due at least in part to inactivation of ferredoxin and pyruvate-ferredoxin oxidoreductase.     

17 alpha-allyl estradiol analogues as candidates for development of high-affinity fluorescein-estradiol conjugates

In order to develop stable, high-affinity fluorescein-estradiol conjugates, the fluorescein moiety must be leashed to the estradiol molecule at a point which interferes least with estradiol's binding to the receptor. Because of the high affinity of 17 alpha-substituted estradiol (e.g. ethynyl estradiol), we investigated a series of 17 alpha-substituted estradiol compounds to determine the optimal properties of a leash at this position. Twelve estradiol derivatives bearing a three-carbon 17 alpha side chain with or without a terminal functional group and with varying degrees of unsaturation were synthesized. Initial comparison of the receptor binding affinities of some of these derivatives suggested that three factors might reduce affinity: internal hydrogen bonding of the 17 beta-hydroxyl proton with an oxygen atom of the 17 alpha side chain; hydrophilicity of the ligand; or steric interference of the side chain with receptor binding. Further comparisons were designed to evaluate the relative contribution of these factors. The results suggest that the relative affinities of these 17 alpha-substituted estradiol derivatives are influenced primarily by the steric interference of the side chains and also by their hydrophilicity. Internal hydrogen bonding involving the 17 beta-hydroxyl proton does not seem to have a profound effect.     

Diagnostic utility of monoclonal antibodies raised against microfilarial excretory-secretory antigens in bancroftian filariasis

Two monoclonal antibodiesWuchereria bancrofti E 33 andWuchereria bancrofli E 34 raised againstWuchereria bancrofti microfilarial excretory-secretory antigens were studied for their diagnostic utility.Wuchereria bancrofti E 34 monoclonal antibody was found to be relatively specific and sensitive in detection of circulating filarial antigen. WhenWuchereria bancrofti E 34 monoclonal antibody was used alongwith immunoglobulin G fraction of human filarial serum immunoglobulins in double antibody sandwich enzyme linked immunosorbent assay. 68% of microfilaraemic sera (26 out of 38). 12% of clinical filarial sera (3 out of 25), 13% endemic normal sera (2 out of 15) and none of the 20 non-endemic normal sera showed the presence of filarial antigen. The filarial antigen detected byWuchereria bancrofti E 34 monoclonal antibody in double antibody sandwich enzyme linked immunosorbent assay is possibly associated with the active stage (microfilaraemia) of infection.     

Characterization of glucose oxidase-negative mutants of a lignin degrading basidiomycete Phanerochaete chrysosporium

The isolation and characterization of glucose oxidase-negative (gox ^-) mutants of Phanerochaete chrysosporium, is described. These mutants are deficient not only in their ability to produce hydrogen peroxide (H₂O₂) but also in lignin degradation (2-¹⁴C-synthetic lignin¹⁴CO₂), ligninase and peroxidase activities, decolorization of the dye poly-R 481, and production of ethylene from -oxo--methylthiobutyric acid (KTBA). The gox ^- mutants retained, albeit at a lower level, the capacity to produce veratryl alcohol, a typical secondary metabolite, and produced conidia at a level comparable to that of the wild type. The addition of ligninase and/or glucose oxidase to a gox ^- mutant (GOX-10) did not enhance its capacity to degrade lignin. The Gox⁺ revertant strains regained glucose oxidase activity, the ability to degrade lignin, as well as the other characteristics that were missing in the gox ^- mutants. The results suggest that the genetic lesion in these mutants affects the regulation of a set of secondary metabolic characteristics.Abbreviations Gox glucose oxidase - KTBA -oxo--methylthiobutyric acid Journal article no. 11740 from the Michigan Agricultural Experiment Station     

Structural organization and nucleotide sequence of mouse c-myb oncogene: activation in ABPL tumors is due to viral integration in an intron which results in the deletion of the 5'' coding sequences.

Bacteriophage libraries of mouse DNA were screened for sequences homologous to the v-myb oncogene and two overlapping clones containing the v-myb related region were isolated. Restriction enzyme mapping, heteroduplex analysis and nucleotide sequence analysis revealed the presence of nine exons. Six of these exons are homologous to the v-myb region while the other three exons are derived from the 5' region which is deleted in the viral oncogene. The sequences downstream to the sixth v-myb exon are not included in the 17 kbp of DNA sequences analyzed in this study. Comparison of the structure of the normal c-myb clone with its rearranged couterpart present in plasmacytoid lymphosarcomas revealed that the rearrangements occur in this locus as a result of viral integration. Present studies demonstrate that such a viral insertion interrupts the c-myb coding region at a region identical to that observed in the generation of the v-myb gene of avian myeloblastosis virus and results in the synthesis of mRNAs that lack the same 5' coding region.     

Optimized Batch Fermentation of Cheese Whey-Supplemented Feedlot Waste Filtrate to Produce a Nitrogen-Rich Feed Supplement for Ruminants

A simple and reliable method is described which allows determination of virus inactivation rates during sludge treatment processes in situ. Bacteriophage f2 was adsorbed onto an electropositive membrane filter which was then sandwiched between two polycarbonate membranes with pores smaller than the virus diameter. The resulting sandwich was fixed in an open filter holder, and several such devices were connected before being exposed in sludge-digesting tanks. The device described prevented uncontrolled virus escape, but allowed direct contact of the various inactivating or stabilizing substances present in the environment tested with the virus adsorbed to the carrier membrane. After exposure to an environment, the surviving fraction of virus was eluted from the inner filter and determined by plaque counting. By using polycarbonate membranes without pores for sandwiching, the influence of temperature alone on virus inactivation could be measured. Thermophilic fermentation at 60 degrees C and at 65 kPa pressure led to a bacteriophage f2 titer reduction of 3.5 log10 units per h, whereas during thermophilic digestion at 54.5 degrees C titers decreased 1.2 log10 units per h. During mesophilic digestion an inactivation rate of only 0.04 log10 units per h was observed. Under these latter conditions, temperature had only a minor effect (19%) on virus inactivation, whereas at 54.5 degrees C during thermophilic digestion heat accounted for 32% of the total inactivation, and during thermophilic fermentation at 60 degrees C temperature and pressure were 100% responsible for virus denaturation.