Influence of Nitrate and Sulfate on the Anaerobic Treatment of Pharmaceutical Wastewater

Anaerobic treatment of wastewater from the pharmaceutical industry, which contained about 3.2 g/L of sulfate, was carried out in an Upflow Anaerobic Sludge Blanket (UASB) reactor. After a startup period of 120 days, a chemical oxygen demand (COD) removal efficiency of more than 90 % was obtained along with an organic loading rate (OLR) of 1.5 g COD/(L day). During the same period, the sulfate removal was about 90 %. However, the performance of the reactor was affected when the loading rate was increased to 2.09 g COD/(L day). It was found that the accumulation of sulfides, combined with a decrease in the pH, affected the reactor performance. In batch reactor studies with pharmaceutical wastewater it was observed that methane production began only after the initiation of nitrate consumption. The denitrification process can inhibit sulfate reduction at high nitrate concentrations, but compared to reactors without nitrate, the sulfate reduction process and sulfide formation were quickly initiated at low nitrate concentrations. The methanogenic activity was however affected by the presence of more than 2 g/L of sulfate.     

Fluidized bed design parameters affecting novel lactic Acid downstream processing.

Lactic acid purification was directly done from fermentation utilizing a fluidized bed column refilled with a strong anionic exchange resin. The purpose of this work was to study the influence of two important design parameters, bed-diameter (D) and bed-height (H), in the lactic acid binding and elution capacity of the matrix. By changing the settled bed height from 2.5 to 5 cm for each diameter of column analyzed it was possible to obtain an 50% increase in the binding capacity of the resin in all experiments. This fact was attributed to a higher contact time between the culture broth and the anionic resin produced by the increase of back mixing and lactic acid residence time.     

Unusual DNA structures at the integration site of an HIV provirus

Supercoiled pHXBc2 DNA (containing the genome of the human immunodeficiency virus type 1 and human sequences) migrated more slowly than linear DNA in native and ethidium bromide agarose gel electrophoresis at 4.5 volts/cm, suggesting the presence of unusual DNA structures. S1 nuclease analysis of pHXBc2 revealed two S1 hypersensitive sites. Site I was located within a 25 bp direct repeat in host DNA 0.6 kB upstream from the 5' LTR. Site II was mapped 0.2 kB upstream from the vif gene start site. Sequence analysis showed that Site I sequences could assume different unusual DNA structures, whereas sequences at Site II could assume either slipped or H-DNA forms. Unusual DNA structures in host DNA may be associated with active chromatin regions and may favor proviral integration.     

Role of cell-mediated immunity in the resistance to experimental sporotrichosis in mice

The in vitro activity of several new imidazoles, cloconazole, sulconazole, butoconazole, isoconazole and fenticonazole, were compared with those of amphothericin B, flucytosine, and three azoles: econazole, miconazole and ketoconazole against isolates of pathogenic Candida. A total of 186 clinical isolates of 10 species of the genus Candida and two culture collection strains were tested by an agar-dilution technique. Isoconazole was the most active azole, followed by butoconazole and sulconazole. Differences between some of the species in their susceptibility to the antifungal agents were noted. Sulconazole and cloconazole had the highest activity in vitro against 106 isolates of C. albicans. Butoconazole and isoconazole were also very active against isolates of C. albicans, and were the most active azole compounds against 80 isolates of Candida spp.     

Binding of beta-galactosidase from rat epididymal fluid to the sperm surface by high-affinity sites different from phosphomannosyl receptors.

beta-Galactosidase, known to be secreted by epithelial cells lining the rat epididymal duct, binds to the surface of spermatozoa from the caudal region with high affinity and in a saturable form. The binding was not inhibited by mannose-6-phosphate, but was inhibited by fructose phosphate derivatives, a peculiarity previously demonstrated for the membranes of epididymal tissue. Fructose phosphate derivatives released 55% of beta-galactosidase activity from the spermatozoa. These results suggest that in the epididymis there is a special transport system for hydrolases, which could be involved in the secretion of enzymes destined for spermatozoa. This transport would require receptors that recognize sugar ligands other than mannose-6-phosphate. These receptors were present in the epididymal tissue and on the sperm surface.     

Effects of atrial natriuretic factor on blood pressure and the renin-angiotensin-aldosterone system

Atrial natriuretic factor (ANF) antagonizes vasoconstriction induced by numerous smooth muscle agonists and also lowers blood pressure in intact animals. ANF has particularly marked relaxant effects on angiotensin II-contracted vessels in vitro. Sensitivity to the blood pressure-lowering effect of ANF in vivo appears to be enhanced in renin-dependent models of renovascular hypertension compared with other experimental hypertensive models. The depressor action of low, possibly physiological doses of ANF in two-kidney, one-clip Goldblatt rats is due to a decrease in total peripheral resistance. On the other hand, high doses of ANF can lower cardiac output, particularly in volume-expanded models such as deoxycorticosterone-salt hypertension. ANF markedly inhibits renin secretion in intact animals, probably via increased glomerular filtration rate and load of sodium chloride to the macula densa. This effect is masked when renal perfusion is impaired (e.g., via unilateral renal artery constriction), in which case ANF may stimulate renin secretion slightly. ANF also reduces plasma aldosterone in vivo and inhibits basal and agonist-induced aldosterone release from isolated adrenal cortical cells. This effect appears to be especially marked for angiotensin-induced aldosterone production in vivo and in vitro. These findings indicate that ANF has potentially important interactions with the renin-angiotensin-aldosterone system and suggest a role for ANF in the homeostatic control of blood pressure as well as of extracellular fluid volume.     

The effect of the lysosomotropic drug chloroquine on the binding of N-acetyl-beta-D-glucosaminidase to mannose-6-phosphate recognizing receptors of rat liver

The binding of N-acetyl-beta-D-glucosaminidase to rat liver receptors was studied in the presence of chloroquine. The association rate constant was not affected in the presence of the drug, while the dissociation rate constant and consequently the equilibrium dissociation binding constant significatively decreased. This results may explain effects of chloroquine on lysosomal enzyme transport found in cultured cells by other authors.     

DETERMINATION OF GUSTATORY SUCROSE THRESHOLD IN WATER BY USE OF A LINEAR SUCROSE GRADIENT

A novel experimental method was developed which allows the determination of the threshold concentration of sucrose by use of a linear sucrose gradient in water. With this method a continuous tasting of the test-liquid is possible. A panel of 15 persons experienced in taste-testing was used. Three gradients of different steepness were applied: 0 to 1.5% (w/w) sucrose in 2 min (I), 3 min (II) and 4 min (III). The results of the new method were compared with those of the standard method (DIN). With gradients I and II we found values which were significantly higher than those of the standard method (I: 0.49% (w/w); II: 0.46% (w/w); DIN: 0.31% (w/w)), whereas with gradient III the same threshold value was found as with the DIN-Method (III: 0.32% (w/w)).     

GENETIC VARIABILITY OF GELIDIUM CANARIENSIS (RHODOPHYTA) DETERMINED BY ISOZYME ELECTROPHORESIS1

The populations of Gelidium canariensis (Grunow) Seoane-Camba from the Canary Islands were analyzed for genetic variability by isozyme electrophoresis in 1989 and 1990. Each population was divided into sporophytic and gametophytic subpopulations. Twenty-three to 27 putative alleles corresponding to 22 gene loci were analyzed. Sev-enteen loci were monomorphic in all six subpopulations, and five were polymorphic in at least one subpopulation. Significant deviations from Hardy-Weinberg equilibrium were found. The amount of genetic variability (percentage of polymorphic loci, mean number of alleles per locus, and average gene diversity) of haploid subpopulations was lower than that of diploid subpopulations. No correlation between genetic distance and geographical distance was found. Low genetic differentiation between sporophytic and gametophytic subpopulations of the same locality was obsewed in two populations. The low genetic diversity and genetic differentiation suggest that the genetic structure of the populations of G. canariensis from the Canary Islands is due to a combination of founder effects and the predominance of asexual reproduction. Initial differences in gene frequencies may have persisted because of insufficient time to reach a higher level of differentiation.