Bacterial reduction of hexavalent molybdenum to molybdenum blue

A bacterium that was able to tolerate and reduce as high as 50 mM of sodium molybdate to molybdenum blue has been isolated from a metal recycling ground. The isolate was tentatively identified as Serratia sp. strain Dr.Y8 based on the carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. ANOVA analysis showed that isolate Dr.Y8 produced significantly higher (P < 0.05) amount of Mo-blue with 3, 5.1 and 11.3 times more molybdenum blue than previously isolated molybdenum reducers such as Serratia marcescens strain Dr.Y6, E. coli K12 and E. cloacae strain 48, respectively. Its molybdate reduction characteristics were studied in this work. Electron donor sources such as sucrose, mannitol, fructose, glucose and starch supported molybdate reduction. The optimum phosphate, pH and temperature that supported molybdate reduction were 5 mM, pH 6.0 and 37°C, respectively. The molybdenum blue produced from cellular reduction exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium, silver, copper and mercury resulted in approximately 61, 57, 80, and 69% inhibition of the molybdenum-reducing activity at 1 mM, respectively. The reduction characteristics of strain Dr.Y8 suggest that it would be useful in future molybdenum bioremediation.     

Characterization and partial purification of <Emphasis Type="Italic">Candida albicans</Emphasis> Secretory IL-12 Inhibitory Factor

Background  

We have previously shown that supernatant from Candida albicans (CA) culture contains a Secretory Interleukin (IL)-12 Inhibitory Factor (CA-SIIF), which inhibits IL-12 production by human monocytes. However, the effect of CA-SIIF on secretion of other cytokines by monocytes is unknown, and detailed characterization of this factor has not been performed.     

Postoperative Deep Vein Thrombosis in Sudanese Patients

The incidence of postoperative deep vein thrombosis diagnosed by radioisotope scanning in 100 Sudanese patients aged 40 or over was 12%. This compares with an incidence of nearly 30% in 542 patients reported from British hospitals using the same diagnostic technique. The reason for the difference is obscure and needs further investigation.     

Molecular evolution of the seed storage proteins of barley, rye and wheat

The major storage proteins (prolamins) of barley, rye and wheat are characterized by the presence of two or more unrelated structural domains, one of which contains repeated sequences. Because of this repetitive structure and their restricted distribution (only in grasses), it has been suggested that the prolamins are of recent origin. Contrary to this hypothesis, we show that parts of the non-repetitive domain of one group of prolamins are homologous with sequences present in a large group of seed proteins from monocotyledonous and dicotyledonous plants; including Bowman-Birk protease inhibitors, cereal inhibitors of alpha-amylase and trypsin, and 2 S globulin storage proteins of castor bean and oil seed rape. This implies an ancient origin for these non-repetitive domains. The origins of the repetitive domains are not known but may lie within the grasses.     

An In Vitro Test for Temperature Sensitivity and Resistance to Meloidogyne incognita in Tomato

An in vitro root explant tissue culture technique is described for determining susceptibility of tomato (Lycopersicon esculentum Mill.) breeding lines and cultivars to the root-knot nematode Meloidogyne incognita. Root explants were taken from 2-day-old seedlings cultured for 30 days at 28 C on Gamborg''s B-5 medium with or without nematode inoculum. The remaining portion of the root and stem from the excised root explants was transferred to soil in pots and grown to maturity in the greenhouse. In vitro root explants were evaluated for growth and occurrence of juveniles, adults, and egg masses. The regenerated plants were used to produce more seed, The proposed technique is simple, reliable, and adapted to routine screening of large numbers of F₁ and F₂ samples, and it utilizes less space than tests performed on intact plants in the greenhouse or growth chamber. Evidence is presented also on the breakdown of resistance to M. incognita under high temperature stress using this in vitro root explant technique.     

Internode length inPisum: Genelkc

A new single gene-recessive internode length mutant inPisum, lkc, is characterized. The internodes oflkc plants are 30–40% shorter than those of comparableLkc plants, and this is attributable to reductions in both cell length and the number of cells per internode. Dwarfism in the mutant is not due to modified gibberellin (GA) levels, as determined by gas chromatography-selected ion monitoring (GC-SIM) for GA₁ and GA₂₀, and bioassay (rice cv. Tan-ginbozu). Furthermore,lkc plants are not as responsive as the wild-type to applied GA₁. The diminished stature oflkc plants appears to result from a direct or indirect interference with the transduction of the GA₁ signal.     

Effect of diffusion limitations and floc size distributions on fermentor performance and the interpretation of experimental data

The biological rate equation that describes the overall rate of substrate uptake by microbial films has been extended to microbial flocs with the aid of a shape parameter. The “solid”- and liquid-phase diffusion limitations are explored and found to depend largely on a dimensionles characteristic size k₂¹V_p/A_p. Procedures are discussed by which k₂¹V_p/A_p can be determined from experimental data on the conversion efficiency in a completely mixed fermentor and measurements carried out on flocs recovered from the fermentor are assessed. Floc size distributions are shown to affect the performance characteristics of a fermentor when some of the flocs are sufficiently large to exhibit a diffusional limitation, and it is concluded that a single mean floc size (k₂¹V_p/A_p)* is sufficient to characterize a given distribution, at least when all the flocs are geometrically similar. The mean floc size closely corresponds to the “surface” mean floc size of the floc size distributions.