The use of bacteriophage as tracers of aerosols liberated by sludge suction appliances

Three bacteriophage tracers were added to 600–1 containers of water and simulated latrine sludge to provide high titres of tracer in aqueous and semi-aqueous media. After a period of mixing and stabilization, media were removed from the containers with suction hoses coupled to the vacuum pump of one of two sludge suction tankers. Exhaust air from the appliances was sampled by cyclone sampler and assayed for the presence of tracer organisms carried over during the emptying process. In the experiments the appliances were operated at different vacuum pump speeds, drawing both aqueous and semi-aqueous (simulated sludge) media. Air around one tanker was also sampled during the emptying, under pressure, of the vacuum vessel. The degree of aerosolization and expulsion of tracer bacteriophage by the vacuum appliances was consistently low, regardless of medium and pump air flow. In contrast, the proportion of tracer retained within the appliances was very high, exceeding the proportion expelled by a minimum of 8log₁₀ orders of magnitude and a maximum of greater than 11log₁₀ orders. The highest total of tracer bacteriophage was recovered during the pressure emptying of the vacuum vessel of one tanker. The results may be used for assessing and comparing potential public health hazards associated with the handling of wastewater sludge by vacuum appliances.     

The prevention of an artifact in receptor binding assay by an improved technique

The intensity of vacuum suction used during filtration of cerebral membranes on glass fiber filters used in the assays of neurotransmitter receptors is a factor in determining the apparent extent of bound radioactivity. This is not related to protein loss during filtration at various speeds nor to rates of dissociation of various ligand-receptor complexes. It appears to be due to the failure of hydrophobic ligands on dry filters, to be readily removed by aqueous media. A means whereby the vacuum can be held constant is described and shown to eliminate this artifact.     

Maximizing collection and minimizing risk: does vacuum suction sampling increase the likelihood for misinterpretation of food web connections?

Molecular tools that characterize the structure of complex food webs and identify trophic connectedness in the field have become widely adopted in recent years. However, characterizing the intensity of predator-prey interactions can be prone to error. Maximizing collection success of small, fast-moving predators with vacuum suction samplers has the potential to increase the likelihood of prey DNA detection either through surface-level contamination with damaged prey or direct consumption within the sampling device. In this study, we used PCR to test the hypothesis that vacuum suction sampling will not cause an erroneous increase in the detection of 'predation', thereby incorrectly assigning trophic linkages when evaluating food web structure. We utilized general (1) Aphidoidea and (2) Collembola primers to measure the predation rates of Glenognatha foxi (Araneae: Tetragnathidae) on these prey collected by hand versus those sampled with a vacuum suction device. With both primer pairs, there was no significant increase in predators screening positive for prey DNA when sampled by vacuum suction versus those predators collected, in parallel, by hand. These results clearly validate the application of vacuum suction sampling during molecular gut-content analysis of predator-prey feeding linkages in the field. Furthermore, we found no evidence that predation was occurring inside the suction sampler because specimens collected were never observed to be feeding nor did they screen positive at greater frequencies than hand-collected individuals. Therefore, it can be concluded that the use of vacuum suction sampling devices (in this case a Modified CDC Backpack Aspirator Model 1412) is suitable for molecular gut-content analysis.     

Performance of vacuum pumps used during implantation of hip endoprostheses with an innovative cementing technique--a comparative study]

The increase in intramedullary pressure during implantation of a cemented total hip prosthesis is the decisive pathogenic factor in the development of an embolism. The logical countermeasure aimed at preventing bone marrow and fat emboli is reduction of pressure. Drainage of the femoral canal enabled by the bone-vacuum cementing technique substantially reduces intraoperative fat embolism and cardiopulmonary events. The aim of the present study was to compare the efficiency of two suction pumps used with this technique. In-vitro and In-vivo measurements of pressure were obtained to characterize the properties of the Vakufix pump and the Sterivap pump. In vitro experiments showed that the length of the suction tube has no influence on the performance of the pumps. A useful vacuum in the medullary canal was achieved In-vivo with both pumps (mean-209.3 mbar). The vacuum obtained with the Vakufix pump was higher (+16%) than that obtained with the Sterivap pump. Owing to the complexity of the system, we would not recommend the use of the Sterivap pump for evacuating the femoral canal.     

Bioventing in Shallow Tundra Overlying Permafrost

The purpose of this research was to investigate the feasibility of suction bioventing for treatment of contaminated tundra soil. Two laboratory-scale venting reactors were prepared with tundra from Arctic Alaska and operated, one for 32?d and the other for 52?d. For each rectangular reactor, suction was applied to a central well screened at mid-depth, while opposite ends of the reactor were screened to serve as air intake zones. The volume of liquid and gas recovered from the suction well was quantified daily. Numbers for heterotrophic organisms, pH, and dissolved organic carbon were quantified in the recovered liquid. The suction pump held a full vacuum (i.e., 101?kPa vac) for the duration of both experiments, indicating continuous obstruction of pneumatic and hydraulic conductivity. In both reactors, the soil in the proximity of the suction well separated from the bulk of the soil, precluding hydraulic communication. Furthermore, the soil nearest the well screen compacted, forming a barrier to appreciable pneumatic conductivity. At the end of operation, the soil was removed and sampled for moisture content, pH, and numbers of heterotrophic organisms at various locations. The results of this study showed that for suction bioventing to be successful in tundra, consolidation of the soil around the well screen must be prevented, as it will cause well isolation and limit both pneumatic and hydraulic conductivities.     

A vacuum benthos sampler suitable for diverse habitats

The vacuum benthos sampler consists of a vacuum chamber equipped with a collecting net connected to the intake of a 12 volt pump, a battery, and a standpipe. Contents of the standpipe are vacuumed while substrate is removed and washed with the exhaust hose. The vacuum chamber is designed for rapid changing of nets during replicate sampling. This sampler is equally efficient in flowing and standing water. It was more effective than a modified Hess sampler for collecting a large variety of benthos from flowing (ca 0.25–0.75 m/s) riffles. Required operation time is variable, but 93% of invertebrates caught in 10 min were captured in the first 5 min during our tests, and there was a 94% mean recovery of released organisms during 10 min of subsequent operation. Advantages over previous suction samplers include interception of organisms before they pass through a pump, return of outlet water to the standpipe, capability of sampling in shallow (20–30 mm) water, and that it can be carried and operated by one person.     

Evaluation of the overland runoff mode of land wastewater treatment for virus removal.

The removal of enteric and tracer viruses by the overland runoff mode of domestic wastewater treatment was evaluated. Raw and primary and secondary treated wastewaters were sprayed onto grass-covered, 36-m soil plots of fine, sandy loam overlying an impermeable clay subsoil. Tracer bacteriophage f2 was seeded into the applied wastewaters, which were subsequently sampled at several points along the length of the plots. Assay of effluent samples revealed modest tracer virus removals of 30 to 60%. Data from timed experiments indicated that advancement of tracer virus to the bottom of the slopes proceeded at the same rate as wastewater, reaching the plot effluents within 50 to 90 min after application. Indigenous enteric virus levels were reduced by approximately 68 to 85% during migration down the treatment slopes. Soil sampling revealed that, although some f2 virus was found associated with the wastewater-saturated topsoil, little penetration of virus into the soil profile occurred. Laboratory soil adsorption studies revealed that poliovirus I was adsorbed much more readily than f2 virus. Comparison of virus removal characteristics during overland runoff with chemical removal characteristics of wastewater did not reveal any obvious correlations that could be used to predict virus removal.     

The Lian Site,an Historic Log Shelter in Yellowstone County,Montana

Abstract

Thomas and Alice Kehoe have recently reported on an example of a Blackfoot clay vessel (Kehoe 1961), Their specimen is most interesting due to the fact that it is sun-dried and exemplifies a very late carry-over of the Blackfoot pottery tradition, The Kehoes postulate that this and similar-type specimens were used as specialized containers for the burning of sweet pine before medicine bundles. In support of this contention, and as a probable archaeological example of this practice, the author reports on the occurrence in central Montana of a similartype vessel which was found in a burnedout log shelter of possible Blackfoot construction, The find is analyzed in the light of Blackfoot-Crow relations during the 18th and 19th centuries.     

Assessment of synergistic combination potential of probiotic and bacteriophage against antibiotic-resistant Staphylococcus aureus exposed to simulated intestinal conditions

This study was designed to evaluate the combined effect of probiotic Lactobacillus rhamnosus and bacteriophage SA11 on the control of antibiotic-sensitive Staphylococcus aureus (ASSA) and antibiotic-resistant S. aureus (ARSA) under the simulated intestinal conditions. The survivability of ASSA and ARSA were determined in the simulated phosphate-buffered saline (PBS)-, trypticase soy broth (TSB)-, and milk-based gastric juices adjusted to pH 2.0, 3.0, and 5.0 at 37 °C for 30 min. The inhibitory effect of bacteriophage SA11 and probiotic on the growth of ASSA and ARSA was evaluated in the simulated intestinal juices at 37 °C for 20 h. The least reductions in the numbers of ASSA and ARSA were observed in the milk-based gastric juices at pH 2.0 (<1 log). No significant changes in the teichoic acid-mediated sliding motility were observed for ASSA and ARSA after 30-min exposure to the simulated gastric juices (pH 2.0, 3.0, and 5.0), responsible for the enhanced bacterial attachment to the epithelial cells. The bacteriophage SA11 was stable down to pH 5.0 and up to 0.06 % bile salts. The bacteriophage SA11 combined with probiotic effectively inhibited the growth of ASSA and ARSA in the simulated intestinal conditions, showing more than 4 log reduction. The relative expression levels of adhesion-related genes (clfA, eno, and fnbA) and efflux-related genes (mdeA, norB, and norC) were less decreased in ARSA than in ASSA after exposure to the simulated gastrointestinal conditions. These results might shed light on the application of bacteriophage to control the ingested antibiotic-resistant foodborne pathogens in the intestinal tract.     

Applications of a Serratia marcescens bacteriophage as a new microbial tracer of aqueous environments

A bacteriophage of Serratia marcescens was evaluated as a tracer in three appropriate aqueous environments and compared with an accepted tracer in two cases. The phage compared favourably with lithium chloride in demonstrating flow characteristics and retention times of various stages in the sewage treatment process. The phage exhibited virtually identical distribution in a marine harbour to spores of Bacillus subtilis var. niger (' B. globigii ') 36–48 h after their addition to a sewage works' final effluent which entered an adjacent bay. Transit times of river water were accurately measured between two points under various flow conditions.     

Tumescent and dry liposuction of lower extremities: differences in lymph vessel injury

Lipectomy is a standard procedure in plastic surgery. Until now, however, there was no definite information about the influence of different liposuction techniques (tumescent versus dry liposuction) on the integrity of lymph collectors during this procedure. To study the effect of these liposuction techniques on the incidence of lymph vessel injury, postmortem lymphatic preparations were done in nine human cadavers (18 lower extremities). Conventional liposuction with a blunt 4-mm cannula in the dry technique (n = 29 regions) was compared with the tumescent technique (n = 26). Liposuction was performed in parallel to the superficial lymph vessels (longitudinal suction) or transversally in an 80-degree to 90-degree angle to the extremity (vertical suction). Careful surgical preparation of different regions followed. A specific macroscopic lymph vessel injury score was applied to differentiate three degrees of lymph vessel lesions according to the extravasation of patent blue. In all lower extremities, postmortem lymph flow occurred as indicated by patent blue staining of the lymph vessels. Injection of fluid that is obligatory during tumescent suction did not result in grade 2 injury. On the contrary, tumescent suction overall produced significantly fewer lymph vessel lesions when compared with the dry technique (p < 0.05). Longitudinal liposuction produced significantly less injury when compared with vertical suction (p < 0.05). Tumescent suction and dry suction were equally effective in removing adipose aspirates, as verified by circumference measurements. In addition, tumescent liposuction is unlikely to cause major lesions of epifascial lymph vessels during suction procedures vertical to the extremity axis. Therefore, in this respect, this technique is superior to dry suction.     

Stability and in vitro DNA packaging of bacteriophages: effects of dextrans, sugars, and polyols.

Attempts were made to increase the efficiency of infectious particle formation during the in vitro assembly of bacteriophage T7 from procapsids and DNA. It was found that dextrans and some smaller, related compounds (sucrose and sorbitol) increase this efficiency by a factor of 8 to 50. Dextrans also inhibited elevated temperature-induced emptying of DNA from bacteriophages T7, P22, and T4, suggesting that the stimulation of assembly is caused, at least in part, by the stabilization of packaged DNA in capsids. The data indicated that the sugars and polyols can slow DNA emptying from bacteriophages at elevated temperature whether they permeate the bacteriophage capsid or not. In contrast, the data suggested that permeation of some particle, probably a capsid, results in inhibition of in vitro T7 assembly.     

Bacteriophage tracer experiments in groundwater

Three tracer experiments employing three different bacteriophage were performed at one groundwater site near Beverley, Humberside. In two of the experiments the bacteriophage were injected into the aquifer by a borehole at a distance of 366 m from the pumping borehole. In the other experiment they were injected at a distance of 122 m. Regular samples were taken of water abstracted at the pumping boreholes as well as from the injection boreholes. The objectives were to: (1) investigate the pattern of bacteriophage recovery from the aquifer; (2) calculate the total number of bacteriophage recovered and the rate of their migration; and (3) detect any differences in bacteriophage behaviour which could be directly related to the morphology of the three bacteriophage. In all experiments the pattern of recovery was similar, exhibiting a peak of high numbers reaching the pumping borehole soon after injection. The highest percentage of original inoculum recovered was 1.9%. In the majority of cases, however, recovery was usually one log10 lower than this. The fastest migration rates were very rapid, reaching 2.8 cm/s in one experiment. No variation in percentage recovery or transit time could be directly attributed to morphology of bacteriophage. The most important factor governing the pattern of migration was undoubtedly the hydrogeological conditions.     

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.     

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.     

Interdependence of bronchial circulation and clearance of 99mTc-DTPA from the airway surface.

The extent to which the systemic vasculature is involved in soluble-particle uptake in the conducting airways has not been studied extensively. In anesthetized, ventilated sheep, 6-10 microl of technetium-99m-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA) was delivered through a microspray nozzle to a fourth-generation airway. Perfusion of the cannulated bronchial artery was varied between control flow (0.6 ml x min(-1) x kg(-1)), high flow (1.8 ml x min(-1) x kg(-1)) or no flow (the infusion pump was stopped). Airway retention of the radioactive tracer was monitored using gamma camera imaging, and venous blood was sampled. During control perfusion, tracer retention at the site of deposition at 30 min averaged 20 +/- 6% (n = 7). With no flow, retention was significantly elevated to 32 +/- 8% (P = 0.03). In another group of sheep (n = 5) with a control retention of 13 +/- 4%, high flow resulted in an increase in tracer (25 +/- 4%; P = 0.04). Maximum blood uptake of tracer was calculated by estimating circulating blood volume and averaged 16% of total activity during control flow. Only during high-flow conditions was 99mTc-DTPA in the blood decreased (10%; P = 0.04). Most of the tracer was cleared by mucociliary clearance as visualized by imaging. This component was substantially decreased during no flow. The results demonstrate that both decreased and increased airway perfusion limit removal of soluble tracer applied to the conducting airways.     

A simplein situ method for the characterization of porosity in growth media

Summary The method presented was based on a very simple approach of the forces operating in the pores of porous media. The standardized time (t_v) needed to infiltrate a given volume of a liquid into a porous medium in a defined state was throught to be an integrated measure of pore geometry and continuity. The state of the pore system was defined by external suction (S) and medium porosity characterized by the parameters k₁ and k₂ in the equation t_v=k₁+k₂ S^−0.5. The method theory was not rejected by experiments with glass beads and selected peat based growth media. The method ranked the media with respect to the probability for satisfactory gas exchange in the order of peat, peat and 26% perlite, peat and 34% perlite, and peat and 44% mineral wool. This ranking was achieved 95 days after the media were filled in containers and exposed to a daily watering procedure. Before this time, the ranking of the media was slightly different, if at all possible. Five days after the containers were filled, only peat and 44% mineral wood was significantly different from the other media. Judged by the standardized time method, the probability for satisfactory gas exchange decreased significantly during the 95 days experiment. This aggravation was supported by measurements of the volume fraction of pores filled with gas. The changes with time were least marked in the medium containing mineral wool.     

Microencapsulation of Bacteriophage Felix O1 into Chitosan-Alginate Microspheres for Oral Delivery

This paper reports the development of microencapsulated bacteriophage Felix O1 for oral delivery using a chitosan-alginate-CaCl₂ system. In vitro studies were used to determine the effects of simulated gastric fluid (SGF) and bile salts on the viability of free and encapsulated phage. Free phage Felix O1 was found to be extremely sensitive to acidic environments and was not detectable after a 5-min exposure to pHs below 3.7. In contrast, the number of microencapsulated phage decreased by 0.67 log units only, even at pH 2.4, for the same period of incubation. The viable count of microencapsulated phage decreased only 2.58 log units during a 1-h exposure to SGF with pepsin at pH 2.4. After 3 h of incubation in 1 and 2% bile solutions, the free phage count decreased by 1.29 and 1.67 log units, respectively, while the viability of encapsulated phage was fully maintained. Encapsulated phage was completely released from the microspheres upon exposure to simulated intestinal fluid (pH 6.8) within 6 h. The encapsulated phage in wet microspheres retained full viability when stored at 4°C for the duration of the testing period (6 weeks). With the use of trehalose as a stabilizing agent, the microencapsulated phage in dried form had a 12.6% survival rate after storage for 6 weeks. The current encapsulation technique enables a large proportion of bacteriophage Felix O1 to remain bioactive in a simulated gastrointestinal tract environment, which indicates that these microspheres may facilitate delivery of therapeutic phage to the gut.     

The healthy heart race: a short-duration, hands-on activity in cardiovascular physiology for museums and science festivals

The "Healthy Heart Race" activity provides a hands-on demonstration of cardiovascular function suitable for lay audiences. It was field tested during the United States of America Science and Engineering Festival held in Washington, DC, in October 2010. The basic equipment for the activity consisted of lengths of plastic tubing, a hand pump, collection containers, clamps, and simulated blood prepared by tinting water with red food coloring. Student participants were first asked to experience the effort required to pump through an unaltered tube. A presenter then applied a strong clamp that pinched each tube downstream from the pump, and students were asked to pump against the increased resistance. The students' observations were then used as the basis for discussions of atherosclerosis and coronary heart disease with the presenters. Distribution of informative postcards during the 2 days of the festival indicated that at least 2,500 students completed the Healthy Heart Race activity. Our experiences to date suggest that the Healthy Heart Race activity can be accomplished effectively in the high-volume, high-distraction environment of a science fair or museum.