Virus removal during groundwater recharge: effects of infiltration rate on adsorption of poliovirus to soil.

Studies were conducted to determine the influence of infiltration rate on poliovirus removal during groundwater recharge with tertiary-treated wastewater effluents. Experiments were conducted at a uniquely designed, field-situated test recharge basin facility through which some 62,000 m3 of sewage had been previously applied. Recharge at high infiltration rates (75 to 100 cm/h) resulted in the movement of considerable numbers of seeded poliovirus to the groundwater. Moderately reduced infiltration rates (6 cm/h) affected significantly improved virus removal. Very low infiltration rates (0.5 to 1.0 cm/h), achieved by partial clogging of the test basin, yielded the greatest virus removal efficiencies.     

Synthesis and biological activity of glycosylated analogs of somatostatin

The synthesis by solid-phase methodology of two glycosylated analogs of somatostatin [Glc-Asn⁵]-SS and [NAcGlc-Asn⁵]-SS is described. These two analogs have been biologically tested on the secretion of pituitary growth hormone, pancreatic glucagon and insulin. The results show that glycosylation of somatostatin on the Asn⁵ residue decreases by a hundred fold the inhibition activity on GH release when tested $\text{in}$$\text{vitro}$. $\text{In}$$\text{vivo}$, since the activity is similar to somatostatin the carbohydrates are probably removed by some enzymatic reaction and thus liberate the full activity of somatostatin.     

A new species of Ceratozamia (Cycadaceae) from San Luis Potosí

A new species ofCeratozamia (Cycadaceae) from San Luis Potosí, Mexico is described. This species differs from all others in the genus by the clustering of leaflets along the rachis.     

Rapid enumeration of Fecal Coliforms in water by a colorimetric beta-galactosidase assay.

The colorimetric beta-galactosidase assay is based upon the enzymatic hydrolysis of the substrate o-nitrophenyl-beta-D-galactoside (ONPG) by fecal coliforms. This technique provides an estimate of the fecal coliform concentration within 8 to 20 h. A 100-ml portion of test sample was passed through a 0.45 micrometer membrane filter. This filter was then incubated at 37 degrees C for 1 h in EC medium followed by the addition of filter-sterilized ONPG. The incubation was continued at 44.5 degrees C until a half-maximum absorbance (at 420 nm) was reached. The time between the start of incubation and the half-maximum absorbance was proportional to the concentration of fecal coliforms present. Escherichia coli (K-12) was used to measure the kinetics of substrate hydrolysis and the response time of different cell concentrations. High cell densities produced an immediate response, whereas 1 cell/ml will produce a response in less than 20 h. In field studies in which samples were taken from a range of grossly polluted streams to relatively clean lake water, a linear correlation between ONPG hydrolysis times and fecal coliform most-probable-number values was established. A total of 302 isolates randomly selected from positive ONPG-EC media, which were derived from 11 different habitats, were identified as E. coli (96.69 percent), Enterobacter cloacae (2.32 percent), Klebsiella pneumoniae (0.66 percent), and Citrobacter freundii (0.33 percent).     

Régulation et signification physiologique de l'aspartate-ammonium lyase (aspartase) de Pseudomonas fluorescens type R

The biosynthesis of aspartate-ammonium lyase, the enzyme which is induced by aspartic acid, is specifically repressed by fumaric acid. In the presence of aspartate, the enzyme permits the deamination of this compound by the cell. Aspartic acid is converted into fumaric acid which is an intermediate in the Krebs'cycle. The reaction may be considered as an anaplerotic sequence. In the absence of aspartic acid in the culture medium, its role is anabolic; the enzyme catalyses the biosynthesis of this amino acid. Therefore it appears that the reversible reaction fumarate+NH₃=aspartate catalysed by aspartase is included in amphibolic processes.     

Distribution of interstitial retinol-binding protein (IRBP) in the vertebrates

Immunoblots of interphotoreceptor matrix preparations from 20 species belonging to six vertebrate classes were probed with antibodies against bovine interstitial retinol-binding protein (b-IRBP). Each preparation displayed an immunoreactive protein band. In the Osteichthyes, the apparent Mr of this band was 67,600 +/- 2,700 (mean +/- SD, n = 8). In two of the Osteichthyes, the band was resolved into a closely spaced doublet. Including previously published data for five mammals and one amphibian, species from the other classes (Chondrichthyes, one species; Amphibia, four species; Reptilia, one species; Aves, one species; Mammalia, nine species) had IRBPs with Mr that averaged 2.0 times that of the Osteichthyes, namely 134,200 +/- 8,600 (mean +/- SD, n = 17). Frog IRBP was very similar to mammalian IRBP in terms of its immunohistochemical distribution (determined with rabbit anti-frog IRBP antibodies), its molecular weight (sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel-filtration chromatography), retinol- and concanavalin A-binding ability, and because it was synthesized and secreted in vitro by the isolated retina but not by the pigmented layers of eye. Goldfish IRBP apparently binds exogenous (3H)-retinol but does not bind concanavalin A and has about half the Mr of frog IRBP. The occurrence of IRBP-like proteins cross-reacting with anti b-IRBP antibodies in the interphotoreceptor matrix of all six major vertebrate classes is consistent with the hypothesis that IRBP is an important element in the vertebrate visual cycle.     

Purification and characterization of an iron-binding protein from the blue crab (Callinectes sapidus)

The presence of an iron-binding protein in the hemolymph of the blue crab (Callinectes sapidus) was detected by gel filtration of 59Fe-labeled hemolymph. The iron-binding protein was purified to homogeneity by ion exchange chromatography. 2. This protein has a mol. wt of 155,000 and consists of a single polypeptide chain with an isoelectric point of 5.0. 3. Analysis of the iron-loaded protein indicates that it has a high affinity for iron and the capacity to bind approximately 10 atoms iron/molecule protein. 4. The isolation of a specific iron-binding protein from the blue crab (Callinectes sapidus) provides additional support for the proposal that such proteins are an ancient evolutionary development not necessarily linked to the appearance of iron proteins (hemoglobin and hemerythrin) as a means for oxygen transport.     

A comparison of the nitrogen metabolic networks of Kluyveromyces marxianus and Saccharomyces cerevisiae

In grape must, nitrogen is available as a complex mixture of various compounds (ammonium and amino acids). Wine yeasts assimilate these multiple sources in order to suitably fulfil their anabolic requirements during alcoholic fermentation. Nevertheless, the order of uptake and the intracellular fate of these sources are likely to differ between strains and species. Using a two-pronged strategy of isotopic filiation and RNA sequencing, the metabolic network of nitrogen utilization and its regulation in Kluyveromyces marxianus were described, in comparison with those of Saccharomyces cerevisiae. The data highlighted differences in the assimilation of ammonium and arginine between the two species. The data also revealed that the metabolic fate of certain nitrogen sources differed, thereby resulting in the production of various amounts of key wine aroma compounds. These observations were corroborated by the gene expression analysis.     

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Although odontogenic keratocysts are benign they are often locally destructive and tend to recur after conservative surgical treatment. They must therefore be distinguished from other cysts of the jaw. Keratocysts possess outpouchings and microscopic daughter cysts from which recurrences may arise. Histologic examination is essential for diagnosis since the appearances on roentgenograms and at operation usually do not reveal the true nature of the lesion. Since many nondental surgeons and pathologists are unaware of odontogenic keratocysts a case is presented in which surgical treatment was originally conservative and finally relatively radical.