Evaluation of a tangential-flow multiple-filter technique for detection of Giardia lamblia cysts in water

A system of tangential-flow filtration was evaluated for use in the detection of Giardia cysts in drinking water. This method was more sensitive in recovering cysts than a frequently used wound-orlon system of through-filtration.     

The Fas/FasL system is a possible regulator of germ cell apoptosis in the testis of Torpedo marmorata

The role played by the Fas/FasL system in the activation of apoptosis during the spermatogenesis of the spotted ray Torpedo marmorata was investigated. By immunohistochemical and western blot techniques it was demonstrated that the Fas/FasL system is amply represented during spermatogenesis of T. marmorata and it could act both via a paracrine and autocrine route: paracrine at the level of immature and mature cysts, autocrine only in mature cysts.     

Dinoflagellate cysts from surface sediments of Saldanha Bay, South Africa: an indication of the potential risk of harmful algal blooms

The distribution and abundance of dinoflagellate cysts from recent coastal sediments in Saldanha Bay, was investigated, and compared to the cyst assemblages of the adjacent coastal upwelling system as reflected in the sediments off Lambert's Bay on the southern Namaqua shelf. Twenty-two cyst types were identified from three sample sites off Lambert's Bay with recorded abundances between 1726 and 1863 cysts ml⁻¹ wet sediment. At least 21 distinctive cyst types were identified from 32 sample sites within Saldanha Bay. Cyst abundance in Saldanha Bay was relatively low, averaging 116 cysts ml⁻¹ wet sediment. The region off Lambert's Bay is especially susceptible to the formation of harmful algal blooms attributed to high biomass dinoflagellate blooms. Owing to these blooms and the retentive circulation characteristics of this area, cyst formation and deposition is high. Blooms can be advected into Saldanha Bay, but their development and duration in the Bay is restricted by the system of exchange that operates between the Bay and the coastal upwelling system, in that there is a net export of surface waters from the Bay. Consequently, fewer cysts are formed and deposited within the Bay thereby reducing the likelihood of in situ bloom development initiated from the excystment of cysts.     

THE CYST OF THE POTATO-ROOT EELWORM (HETERODERA ROSTOCHIENSIS WOLLENWEBER) AS A HATCHING UNIT

Two series of experiments are described: in one, the hatching of half and whole cysts is compared, in some cases after they have been subjected to tryptic digestion; in the second series, the hatching of free eggs is considered.
Total emergence from halved cysts was very much greater than that from intact cysts. Emergence from trypsin-treated halved cysts was greater than emergence from control halved cysts, suggesting that the enzyme affects the egg shell or the larva inside; it is possible, however, that the enzyme also affects the cyst wall, for treated whole cysts shrink more rapidly and to a greater extent when exposed to air.
Total emergence from trypsin-treated whole cysts did not differ significantly from that of untreated whole cysts, unlike previous findings (Ellenby, 1946 a); however, emergence began sooner from these cysts. Halving the cysts also resulted in earlier emergence, the biggest effect being produced by a combination of both trypsin and subsequent halving.
The variability shown by the intact cysts was considerably greater than that shown by the halved cysts; halving the cysts reduced the coefficient of variation from 0·55 for whole untreated cysts, to 0·19 for untreated halved cysts, and to 0·13 for trypsin-treated halved cysts. Apparently some of the variability in emergence, like the limitation of total emergence, is bound up with the nature of the cyst as a more or less closed system.
In two experiments the hatching of eggs freed from half-cysts was compared with that of eggs in their fellow intact halves. In one experiment there was no difference; in the other it was possible to show that a higher proportion of free eggs hatched. Evidently factors limiting hatching may operate among eggs in a mass, even though they are no longer completely enclosed in a cyst.     

Development and testing of a filter system for isolation of Giardia lamblia cysts from water

An inexpensive, practical, and reliable method for isolation of Giardia lamblia cysts from potable and environmental water has been developed from commercially available components. This system was successfully used to isolate cysts from well water associated with a family outbreak of giardiasis.     

Development and testing of a filter system for isolation of Giardia lamblia cysts from water.

An inexpensive, practical, and reliable method for isolation of Giardia lamblia cysts from potable and environmental water has been developed from commercially available components. This system was successfully used to isolate cysts from well water associated with a family outbreak of giardiasis.     

Primary infection with mouse-derived cysticercoids of Hymenolepis nana prepared from baby or adult mice and secondary infections with eggs or cysticercoids

Oral infection with mouse-derived cysticercoids (cysts) of Hymenolepis nana on day 0 did not make the 5 ± 1 week old mouse host immune to egg challenge by day 7 of the prepatent period, although the number of cyst-derived tapeworms was 1000 times greater than that of egg-derived tapeworms sufficient to make the host immune by day 7. Neither cysts recovered from immunologically competent 5 ± 1 week old donor mice, which should have become immune within 2 days of egg inoculation, nor those from incompetent 5–7 day-old baby mice given eggs when 0–2 days old made the host immune. The time course of differentiation of cysts in baby mice was not different from that in 5 ± 1 week-old mice. Mice infected twice with cysts on days 0 and 4 did not become immune either. Rapid protective immunity against egg challenge was acquired by inoculation exclusively with eggs but not with cysts. Apparently cysts differ from oncospheres in their immunogenicity. The importance of cysts for analysing the mouse—H. nana system from the immunological point of view is discussed.     

Effects of Birds Ingesting Heterodera rostochiensis Cysts on Viability of Eggs and Larvae

Rate of passage through the digestive systems and effects of ingestion on viability of contents of cysts of Heterodera rostochiensis were determined in feeding trials with pigeons, thrushes, starlings, cowbirds, sparrows, and quails. Depending upon species of birds, 12-82% of the cysts ingested passed through the digestive system within 0.5 h. Pigeons required 6 h for complete evacuation. All other birds cmnpletely evacuated ingested cysts from their digestive systems within 3 h. Contents of cysts were nonviable if they were retained in the digestive system of starlings for more than 1.5 h, pigeons more than 1 h, or other birds more than 0.5 h. Cyst contents were nonviable if they remained in contact with excreta from cowbirds or quails for 4 h, thrushes for 96 h, or other species for 72 h after passage. Viability of contents of cysts was inversely related to exposure to excreta-filtrate concentration. Larvae failed to emerge from cysts that were exposed to a 25% concentration of excreta filtrate from starlings, 50% concentration from pigeons or thrushes, or 100% concentration of excreta filtrates from each of the other species. Cysts that were subjected to 44 C (avg. body temperature of cowbirds) for more than 3.5 h were nonviable. Cysts that passed through birds and collected with excrement on polyethylene or soil produced no infective larvae on potato.     

Changes in ribosomal proteins in developing Artemia salina embryos

Ribosomal proteins from cysts and nauplii of Artemia salina were analyzed by three kinds of two-dimensional polyacrylamide gel electrophoresis. The basic-acidic and basic-SDS gel systems were used to compare the basic ribosomal proteins, and some changes were observed between the cysts and nauplii in proteins S6, S14, and L24. The phosphorylation of protein S6 was increased in the nauplii. Basic proteins S14 and L24 in the cysts changed and none of the corresponding proteins in the nauplii were detected at the same positions on two-dimensional gels as in the cysts. The acidic-SDS gel system was used to compare the acidic proteins in ribosomes and it was revealed that an acidic protein, AX (Mr = 24,000), in the cysts was not present in the ribosomes from the nauplii. The ribosomal activities as to the formation of an 80S initiation complex with globin mRNA and poly(U)-directed polyphenylalanine synthesis were compared. There was no significant difference between the cyst and nauplius ribosomes.     

Prediction of viability of porcine neurocysticercosis with proton magnetic resonance spectroscopy: correlation with histopathology

Neurocysticercosis (NCC) is the most frequent parasitic disease of central nervous system. In our earlier study, we had observed creatine [(creatine + phosphocreatine); (tCr)] on ex vivo proton MR spectroscopy (1H MRS) in some of the cysticercus cyst fluid samples obtained from swine's brain parenchyma. In current study, swine brains of freshly slaughtered animals naturally infected with NCC were subjected to ex vivo magnetic resonance (MR) imaging on a 1.5Tesla MR system. Cysticercus cysts (n = 12) were removed from these brains and were labeled depending upon presence or absence of edema around cysts as observed on imaging. Cysticercus cyst fluid (100 microl) was subjected to different 1H MRS experiments and results were compared with histopathological examinations to look for any relationship between tCr and parameters like quantification of musculature, and cellular infiltration in wall of the parasite. Histopathology of cyst wall was categorized into two groups based on cellular characteristics and the amount of musculature. Grade I cysts (n = 5) with no or minimal inflammation and large amount of musculature showed tCr on 1H MRS. However, grade II cysts (n = 7) with profuse inflammation and less amount of musculature in the cyst wall lacked tCr. Higher amount of musculature in grade I cysts was associated with higher concentration of tCr in the cyst fluid (r2 = 0.93, P = 0.007). Creatine appears to be a marker of innocuous and viable NCC.     

An improved method of isolating Pneumocystis carinii from infected rat lungs

A new method of isolating Pneumocystis carinii from infected lungs of cortisonized rats is described. Clumping of parasites and host lung material was diminished by suspension of macerated Pneumocystis-laden rat lung in a modified calcium, magnesium-free Hanks' balanced salts solution at physiologic pH and osmolality, containing the wetting agent G-acid. After washing, this material was suspended in a second buffer system for digestion. The digestion step was done in the same buffer but with the addition of calcium, magnesium, collagenase, hyaluronidase and deoxyribonuclease. These innovations allowed enumeration of trophozoites as well as cysts. Following digestion, the parasites were separated from particulate host lung debris by Percoll density gradients designed to pellet the debris, leaving parasites in the gradient. Density studies done prior to this step revealed that trophozoites and non-nucleated cysts had similar densities, 1.028 g/ml, whereas nucleated cysts were heavier at 1.030 g/ml. Particulate host lung debris could be removed due to its heavier density, 1.040 g/ml. The significance of this study includes: relatively clump-free suspensions of infected rat lung, enumeration of trophozoites as well as cysts, and characterization of nucleated cysts.     

Incidence of Spinal Perineurial (Tarlov) Cysts among East-European Patients

The spinal perineurial cyst (Tarlov) is a dilatation between the perineurium and endoneurium of spinal nerve roots, located at level of the spinal ganglion and filled with cerebrospinal fluid but without communication with the perineurial subarachnoid space. The aim of the study was to evaluate it incidence among East-European patients. The retrospective data collected during various magnetic resonance spinal examinations and stored on the picture archiving and communication system was analyzed for an incidence of perineurial cysts. From among 842 patients that underwent examination, 75 cases perineurial cysts were revealed. In 22 cases single anomalies were found. In remaining 53 cases, multiple uni- or less frequently bilateral changes were noted. The most common position was the sacral canal, particularly the level of S2 and S3. Occasionally, cysts were also visible on the cervical, thoracic and lumbar level. Incidence of sacral perineurial cysts was significantly higher in females than in males. Similar data was found for single and multiple changes despite of their localization. Insignificant changes were seen for patient age and cyst size. Perineurial spinal cysts were the most frequently observed on the sacral level and such changes were more common in females.     

Comparative Outcomes of the Two Types of Sacral Extradural Spinal Meningeal Cysts Using Different Operation Methods: A Prospective Clinical Study

This prospective study compares different clinical characteristics and outcomes of patients with two types of sacral extradural spinal meningeal cysts (SESMC) undergoing different means of surgical excision. Using the relationship between the cysts and spinal nerve roots fibers (SNRF) as seen under microscope, SESMCs were divided into two types: cysts with SNRF known as Tarlov cysts and cysts without. The surgical methods were tailored to the different types of SESMCs. The improved Japanese Orthopedic Association (IJOA) scoring system was used to evaluate preoperative and postoperative neurological function of the patients. Preoperative IJOA scores were 18.5±1.73, and postoperative IJOA scores were 19.6±0.78. The difference between preoperative and postoperative IJOA scores was statistically significant (t = -4.52, p = 0.0001), with a significant improvement in neurological function after surgery. Among the improvements in neurological functions, the most significant was sensation (z=-2.74, p=0.006), followed by bowel/bladder function (z=-2.50, p=0.01). There was a statistically significant association between the types of SESMC and the number (F=12.57, p=0.001) and maximum diameter (F=8.08, p=0.006) of the cysts. SESMC with SNRF are often multiple and small, while cysts without SNRF tend to be solitary and large. We advocate early surgical intervention for symptomatic SESMCs in view of significant clinical improvement postoperatively.     

Giardia cysts and Cryptosporidium oocysts detection in the intake and rapid filter system in a water purification plant

Water samples, taken from the intake and rapid filter system of a water purification plant, were analyzed using an immunofluorescence antibody method for detecting the presence of Giardia cysts and Cryptosporidium oocysts. Giardia cysts and Cryptosporidium oocysts were found in the intake water from zero to 38.7 cysts/100 l and 1.7–50.5 oocysts/100 l with averages of 9.6 cysts/100 l and 19.4 oocysts/100 l. Giardia cysts and Cryptosporidium oocysts were also detected in the samples taken from the rapid filtration unit with mean concentrations of zero to 2.3 cysts/100 l and 0–2.5 oocysts/100 l, respectively. The efficacy of the rapid filter in suspended material and (oo)cyst removal was significant. The removal late was 56–97% for suspended material and 69–100% for the (oo)cysts.     

Photocatalytic disinfection of Giardia intestinalis and Acanthamoeba castellani cysts in water

In this study, disinfection of water containing Giardia intestinalis and Acanthamoeba castellani cysts with TiO2 and modified catalyst silver loaded TiO2 (Ag-TiO2) was investigated. Destruction of the parasites was evaluated after UV illumination of the suspension consisting 5 x 10(8)-13.5 x 10(8)cysts/mL in the presence of 2g/L neat or modified TiO2 at neutral pH. In the initial stage, the solid photocatalyst particles penetrated the cyst wall and then oxidant species produced by TiO2/UV destroyed both cell wall and intracellular structure. In the case of G. intestinalis inactivation (disinfection) performance of TiO2/UV system reached 52.5% only after 25 min illumination and total parasite disinfection was achieved after 30 min illumination. However, silver loaded TiO2 seemed to be more effective as this loading provided better catalytic action as well as additional antimicrobial properties. Cell viability tests showed that parasite cysts, their walls in particular, were irreversibly damaged and cysts did not re-grow. Nevertheless the studied system seemed to be ineffective for the inactivation of A. castellani. Inactivation percentages of TiO2/UV and Ag-TiO2/UV systems were far lower than that of UV alone, being 50.1% and 46.1%, respectively.     

Interrelationships between water and cellular metabolism in Artemia cysts. XI. Density measurements

Cysts of the crustacean Artemia are a useful model for studies on intracellular water because they are capable of essentially complete and reversible desiccation. We have used a variety of techniques on this system, the present work being an attempt to estimate the density of intracellular water (rho w). The density of individual cysts was evaluated from sedimentation velocity. Heptane displacement methods were used to determine the volume of a known mass of cysts, from which the density was calculated. The two methods produce comparable results. It was shown that the densities and water contents of large masses of cysts accurately reflect those of individual cysts. Cyst densities (rho c) were determined over the entire range of water content from 0 to 0.63 weight fraction of water (Wf), and temperature dependence was measured for 0.61 Wf over 2-41 degrees C. The following refer to 25 degrees C. No marked change was detected in rho c until the water content exceeded 0.15 Wf, at which rho c decreased as a linear function of Wf to maximum water content. However, the cyst does not behave ideally in the sense that the densities of the nonaqueous components and added water are not additive as a function of Wf. The partial specific volume of water in cysts at maximum hydration was estimated to be 3% larger than that of pure water. These observations are compared with density measurements on other systems, and with previous findings on the physical properties of water in this system.     

A ten-year survey of Giardia cysts in drinking water supplies of Seoul, the Republic of Korea

To understand the distribution of Giardia cysts in drinking water supplies in Seoul, Korea, we collected water samples quarterly at 6 intakes in the Han River, its largest stream and 6 conventional water treatment plants (WTPs) serving drinking water, from 2000 to 2009. Giardia cysts in each of 10 L water were confirmed in 35.0% of intake water samples and the arithmetic mean was 1.65 cysts/10 L (range 0-35 cysts/10 L). The lowest cyst density was observed at Paldang and Kangbuk intakes, and the pollution level was higher at 4 intakes downstream. It seemed that these 4 intakes were under influence of Wangsuk stream at the end of which cysts were found in all samples with the mean of 140 cysts/10 L. The annual mean number of cysts was 0.21-4.21 cysts/10 L, and the cyst level at the second half of the 10 years was about 1/5 of that at first half on average. The cysts were more frequently found in winter, and their mean density was 3.74 cysts/10 L in winter and 0.80-1.08 cysts/10 L in other seasons. All finished water samples collected at 6 WTPs were negative for Giardia in each of 100 L sample for 10 years and cyst removal by physical process was average 2.9-log. It was concluded that conventional water treatment at 6 WTPs of Seoul appears to remove the cysts effectively under the present level of their source water. Domestic wastewater from the urban region could be an important source of Giardia pollution in the river.     

Detection of respiratory enzyme activity in Giardia cysts and Cryptosporidium oocysts using redox dyes and immunofluorescence techniques.

The fluorescent redox dye 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), combined with fluorescein-labeled antibodies, was tested for the simultaneous detection of the respiratory electron transport system (ETS) activity and enumeration of Giardia cysts and Cryptosporidium oocysts by spectral microfluorometry and epifluorescence microscopy. The reduction of CTC and p-iodonitrotetrazolium violet (INT), a non-fluorescent redox dye, was compared with propidium iodide (PI) and fluorescein diacetate (FDA) for the measurements of Giardia cyst viability over time. According to the PI and FDA staining techniques, nearly 60% of the cysts tested viable at the beginning of the observations; after 21 days their viability decreased to 5%. The redox dyes indicated that approximately 4-10% of the cysts were metabolically active 48 h after they were shed, followed by a decline in enzyme activity to near undetectable levels after 4 days. Spectral analysis on individual cysts indicated that the fluorescence emission of the reduced CTC and the fluorescein-labeled antibodies is distinctive for each compound and suitable for their simultaneous determination by microphotometry, flow cytometry and epifluorescence microscopy. The fluorescence signal remained without alteration when the cysts were transferred onto microscope slides coated with an optical embedding medium and stored at -20 degrees C. The fluorescence intensity of the reduced CTC, when properly standardized, can provide quantitative measurements of ETS activity of the cysts. This is the first report of a method to determine enzyme redox activity on intact cysts applicable to water, laboratory and animal samples.     

Predictive value of palpation per rectum vs milk and serum progesterone levels for the diagnosis of bovine follicular and luteal cysts

Diagnosis of bovine follicular and luteal cysts by palpation per rectum was compared with diagnosis by progesterone status, as determined by an enzymeimmunoassay (EIA). A 2x2 contingency table analysis allowed the calculation of predictive value, sensitivity and specificity for the palpation diagnosis of both cyst types. The results were 75.0, 61.9 and 50.0% for follicular cysts and 35.1, 50.0 and 61.9% for luteal cysts, respectively. The EIA results were compared to radioimmunoassay (RIA). The predictive value for a low progesterone determination (<5ng/ml) was 91.8% and for high progesterone (5ng/ml or >) it was 83.3%. The sensitivity and specificity for the EIA were both 88.2%. Within the EIA system, milk and serum samples agreed a total of 85 out of 87 times (97.7%). Definitive diagnosis of follicular or luteal cysts should not be based upon palpation per rectum alone. The EIA was found to be the better definitive diagnostic technique.     

The influence of processing and temperature conditions on hatching of resting eggs of Streptocephalus proboscideus (Crustacea: Branchiopoda: Anostraca)

In large freshwater branchiopods, erratic hatching success of resting eggs is a major obstacle to various applications. Lack of knowledge of the diapause-regulating processes makes control of hatching difficult. In the Sudanese fairy shrimp Streptocephalus proboscideus cysts are considered to include a diapausing and a quiescent fraction. To effect hatching, diapausing cysts have to be activated, while the quiescent portion has to be triggered by suitable environmental conditions. Of several attempts to control hatching with varying production, processing, and incubation conditions, only a few treatments proved consistently successful. Cysts were produced in an indoor culture system under controlled conditions and were harvested, washed, and dried according to defined procedures before processing (if any) and incubation. Hatchability (first-day and cumulative) was consistently higher in chemically decapsulated than in untreated (non-decapsulated) cysts at 25 °C. At a temperature of 28 °C, hatching was comparable in untreated and in decapsulated cysts and was significantly higher than at 25 °C. Pre-treatment with 7.5% NaOCl for 5–10 minutes, resulted in higher hatching than other decapsulation procedures and durations. It is believed that the decapsulation and temperature treatments were only effective in triggering quiescent cysts but did not activate the diapausing fraction.