Regeneration of pleated filters used to concentrate enteroviruses from large volumes of tap water.

Pleated cartridge filters are capable of concentrating enteroviruses from large volumes (well over 2,000 liters) of tap water. These epoxy-fiberglass filters can be regenerated if they are treated with 0.1 N NaOH or autoclaved to inactivate any contaminating virus. The regenerated filters regained their ability to concentrate viruses from water at high flow rates.     

Vasoactive intestinal peptide causes peristaltic contractions in the esophageal body

Vasoactive intestinal peptide (VIP) caused a dose-dependent fall in lower esophageal sphincter (LES) pressure and dose-dependent contractions in the body of the esophagus. The response to VIP in the esophagus or LES was not modified by atropine, phentolamine, haloperidol, pyrilamine, methysergide, indomethacin and tetrodotoxin, showing that it exerts direct action at the esophageal smooth muscle. These studies suggest that VIP causes contraction in the esophageal body and relaxation of the LES by a direct action on the smooth muscle. It is possible that VIP may be the common mediator of noncholinergic, nonadrenergic neurons that cause relaxation of the lower esophageal sphincter and contraction in the esophageal body.     

Movement of Endotoxin Through Soil Columns

Land treatment of wastewater is an attractive alternative to conventional sewage treatment systems and is gaining widespread acceptance. Although land application systems prevent surface water pollution and augment the available water supplies, the potential dangers to human health should be evaluated. Since sewage may contain high amounts of bacterial endotoxin, the removal of endotoxin from sewage by percolation through soil was investigated. It was found that 90 to 99% of the endotoxin was removed after travel of sewage through 100 to 250 cm of loamy sand soil. When distilled water was allowed to infiltrate into the soil to simulate rainfall, the endotoxin was mobilized and moved in a concentrated band through the soil column. On testing samples from actual land treatment sites, as much as 480 ng of endotoxin per milliliter was found in some groundwater samples. The presence of endotoxin in potable water is known to be a potential problem under some circumstances, but the importance of endotoxin in water supplies has not been fully assessed. Therefore, the design, operation, and management of land application systems should take into account the fate of endotoxin in groundwater beneath the sites.     

Regeneration of pleated filters used to concentrate enteroviruses from large volumes of tap water.

Pleated cartridge filters are capable of concentrating enteroviruses from large volumes (well over 2,000 liters) of tap water. These epoxy-fiberglass filters can be regenerated if they are treated with 0.1 N NaOH or autoclaved to inactivate any contaminating virus. The regenerated filters regained their ability to concentrate viruses from water at high flow rates.     

Action Spectra for Conversions of Phycochrome c from Nostoc muscorum

The reversibly photochromic pigment, phycochrome c, was extracted from the blue-green alga Nostoc muscorum strain A. Action spectra were determined for in vitro conversions of the pigment from the short wavelength to the long wavelength form and vice versa. The action peak for the absorbance decrease at 650 nm is at 630 nm. During this decrease there is only a slight increase of the absorbance in the green region. Green and yellow light (maximum efficiency at 580 nm) completely restores absorbance at 650 nm. The observations are explained by the existence of three spectrally different forms of phycochrome c: P^c₆₃₀ and P^c₆₅₀ which equilibrate in darkness and P^c₅₈₀ which is reversibly photoconvertible to P^c₆₃₀. We have also measured the absorbance changes brought about by saturating irradiations with light of various wavelengths (“photostationary state spectrum”). Extreme photostationary states were obtained with about 650 nm and 500 nm light.     

Effects of Frost Hardening and Dehardening on Photosynthetic Electron Transport and Fluorescence Properties in Isolated Chloroplasts of Pinus silvestris

Photosynthetic electron transport and low-temperature fluorescence emission properties have been analyzed in isolated chloroplasts during the course of frost hardening and dehardening of Pinus silvestris L. Both the partial electron-transport reactions (H₂O DPIP and Asc./DPIP NADP) and the overall electron transport (H₂O — NAPD) showed decreasing capacities during the course of hardening. Upon exposing the plants to ?5°C and high irradiance a block in the electron-transport chain between the two photosystems developed, whereas the partial reactions still showed activities. The decrease in activity of PSl was accompanied by a decrease in P700 content, as determined by light oxidation of P700, which indicates a correlation between the two changes. Hardening also induced changes in the in vivo chlorophyll organization. During the course of hardening the fluorescence emission bands F692 and F726 decreased relative to F680. These changes were more pronounced if the plants were treated in high than in low irradiance. This suggests a greater destruction of the chlorophyll antennae in close association with the two photoreactions than in the so-called light-harvesting chlorophyll a/b antenna. During dehardening basically the reverse of the changes observed during hardening occurred. The recovery of secondary needles was complete, whereas primary needles only partly recovered.     

Carbon Oxysulfide Inhibition of the CO(2)-Concentrating Process of Unicellular Green Algae

Carbonyl sulfide (COS), a substrate for carbonic anhydrase, inhibited alkalization of the medium, O₂ evolution, dissolved inorganic carbon accumulation, and photosynthetic CO₂ fixation at pH 7 or higher by five species of unicellular green algae that had been air-adapted for forming a CO₂-concentrating process. This COS inhibition can be attributed to inhibition of external HCO₃⁻ conversion to CO₂ and OH⁻ by the carbonic anhydrase component of an active CO₂ pump. At a low pH of 5 to 6, COS stimulated O₂ evolution during photosynthesis by algae with low CO₂ in the media without alkalization of the media. This is attributed to some COS hydrolysis by carbonic anhydrase to CO₂. Although COS had less effect on HCO₃⁻ accumulation at pH 9 by a HCO₃⁻ pump in Scenedesmus, COS reduced O₂ evolution probably by inhibiting internal carbonic anhydrases. Because COS is hydrolyzed to CO₂ and H₂S, its inhibition of the CO₂ pump activity and photosynthesis is not accurate, when measured by O₂ evolution, by NaH¹⁴CO₃ accumulation, or by ¹⁴CO₂ fixation.     

Cloning, characterization, and nucleotide sequence of a gene encoding Microbispora bispora BglB, a thermostable beta-glucosidase expressed in Escherichia coli.

Genomic DNA fragments encoding beta-glucosidase activities of the thermophilic actinomycete Microbispora bispora were cloned into Escherichia coli. Transformants expressing beta-glucosidase activity were selected by their ability to hydrolyze the fluorogenic substrate 4-methylumbelliferyl-beta-D-glucoside. Two genes encoding beta-glucosidase activity were isolated and distinguished by restriction analysis, Southern hybridization, and the substrate specificities of the encoded enzymes. One gene, bglB, encoded a beta-glucosidase that was expressed intracellularly in E. coli. It exhibited a molecular mass of approximately 52,000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and 51,280 Da by nondenaturing gradient PAGE, a pI of 4.6, and temperature and pH optima of 60 degrees C and 6.2, respectively. Cloned BglB showed greater activity against cellobiose than against aryl-beta-D-glucosides and was thermostable, retaining about 70% of its activity after 48 h at 60 degrees C. BglB activity is activated two- to threefold in the presence of 2 to 5% (0.1 to 0.3 M) glucose. The DNA sequence of the 2.2-kb insert carrying bglB has been determined. An open reading frame which codes for a protein of 473 amino acids with a predicted molecular mass of 52,227 Da showed significant homology (40 to 47% identity) with beta-glucosidases from glycosal hydrolase family 1.     

Multilaboratory evaluation of methods for detecting enteric viruses in soils.

Two candidate methods for the recovery and detection of viruses in soil were subjected to round robin comparative testing by members of the American Society for Testing and Materials D19:24:04:04 Subcommittee Task Group. Selection of the methods, designated "Berg" and "Goyal," was based on results of an initial screening which indicated that both met basic criteria considered essential by the task group. Both methods utilized beef extract solutions to achieve desorption and recovery of viruses from representative soils: a fine sand soil, an organic muck soil, a sandy loam soil, and a clay loam soil. One of the two methods, Goyal, also used a secondary concentration of resulting soil eluants via low-pH organic flocculation to achieve a smaller final assay volume. Evaluation of the two methods was simultaneously performed in replicate by nine different laboratories. Each of the produced samples was divided into portions, and these were respectively subjected to quantitative viral plaque assay by both the individual, termed independent, laboratory which had done the soil processing and a single common reference laboratory, using a single cell line and passage level. The Berg method seemed to produce slightly higher virus recovery values; however, the differences in virus assay titers for samples produced by the two methods were not statistically significant (P less than or equal to 0.05) for any one of the four soils. Despite this lack of a method effect, there was a statistically significant laboratory effect exhibited by assay titers from the independent versus reference laboratories for two of the soils, sandy loam and clay loam.