Determination of Growth-Phase Dependent Influences Exerted by Prions on Yeast Lipid Content Using HPTLC-Densitometry.

Prions of the baker's yeast Saccharomyces cerevisiae allow for the inheritance of complex traits based solely on the acquisition of cytoplasmic protein aggregates and confer distinctive phenotypes to the cells which harbor them, creating heterogeneity within an otherwise clonal cell population. These phenotypes typically arise from a loss-of-function of the prion-forming protein that is unable to perform its normal cellular function(s) while sequestered in prion amyloid aggregates, but the specific biochemical consequences of prion infection are poorly understood. To begin to address this issue, we initiated a direct investigation into the potential control that yeast prions exert over fungal lipid content by utilizing the prions [URE3] and [PSI+], the first two prions discovered in yeast. We utilized silica gel high-performance thin-layer chromatography (HPTLC)-densitometry to conduct pair-wise quantifications of the relative levels of free sterols, free fatty acids, and triacylglycerols [petroleum ether-diethyl ether-acetic acid (80:20:1) mobile phase, phosphomolybdic acid (PMA) detection reagent]; steryl esters and squalene (hexane-petroleum ether-diethyl ether-acetic acid (50:20;5:1), PMA]; and phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol (chloroform-diethyl ether-acetic acid (65:25:4.5), cupric sulfate-phosphoric acid) in otherwise clonal prion-infected ([PSI+] or [URE3]) and prion-free ([psi-] or [ure-o]) cells in two growth phases: log-phase and stationary phase. Our analysis revealed multiple statistically significant differences (p < 0.00625) between prion-infected and prion-free cells. Interestingly, prion-induced changes varied dramatically by growth phase, indicating that prions exert differential influences on cell physiology between log and stationary growth. Further experimental replication and extension of the analysis to other prions is expected to resolve additional physiological effects of prion infection. This investigation demonstrates that HPTLC-densitometry is an effective method for studying prion-induced alterations in lipid content in yeast.

Intrinsic Religiosity and Hypertension Among Older North American Seventh-Day Adventists.

A unique lifestyle based on religious beliefs has been associated with longevity among North American Seventh-day Adventists (SDAs); however, little is known about how religion is directly associated with hypertension in this group. Identifying and understanding the relationship between hypertension and its predictors is important because hypertension is responsible for half of all cardiovascular-related deaths and one in every seven deaths in the USA. The relationship between intrinsic religiosity and hypertension is examined. Cross-sectional data from the Biopsychosocial Religion and Health Study (N = 9581) were used. The relationship between intrinsic religiosity and hypertension when controlling for demographics, lifestyle variables, and church attendance was examined using binary logistic regression. While lifestyle factors such as vegetarian diet and regular exercise were important predictors of reduced rates of hypertension, even after controlling for these, intrinsic religiosity was just as strongly related to lower hypertension rates as the lifestyle factors. This study is the first to examine the relationship between intrinsic religiosity and hypertension among North American SDAs and demonstrates that in addition to the positive effects of lifestyle choices on health noted in the group, religion may offer direct salutary effects on hypertension. This finding is particularly important because it suggests that religiosity and not just lifestyle is related to lower risk of hypertension, a leading cause of death in the USA.

Religious Social Support and Hypertension Among Older North American Seventh-Day Adventists.

Seventh-day Adventists have been noted for their unique lifestyle, religious practices and longevity. However, we know little about how religion is directly related to health in this group. Specifically, we know nothing about how religious social support is related to hypertension. Using data from the Biopsychosocial Religion and Health Study, we carried out a cross-sectional study of 9581 and a prospective study of 5720 North American Seventh-day Adventists examining new 534 cases of hypertension occurring up to 4 years later. We used binary logistic regression analyses to examine study hypotheses. Of the religious social support variables, in both the cross-sectional and prospective study only anticipated support significantly predicted hypertension, but the relationship was mediated by BMI. There were no significant race or gender differences. The favorable relationships between anticipated support and hypertension appear to be mediated by BMI and are an indication of how this dimension of religion combined with lifestyle promotes good health, specifically, reduced risk of hypertension.

Post-discharge services and psychiatric rehospitalization among children and youth.

This study examined risk and determinants of rehospitalization of children and adolescents (n = 186) following a first psychiatric hospitalization. It specifically examined the role of post-discharge services. Data were collected for a 30-month follow-up period through structured telephone interviews with caregivers and case record abstractions. 43% of youth experienced readmissions during the follow-up period. Risk of rehospitalization was highest during the first 30 days following discharge and remained elevated for 3 months. 72% of youth received 284 post-discharge services during the follow-up period, which significantly reduced the risk of rehospitalization. Longer first hospitalizations and a higher risk score at admission increased risk.

Effects on the neutral lipid contents of the liver, ileum and serum during experimental schistosomiasis.

During infection of vertebrate hosts with Schistosoma mansoni,worm eggs trapped in host tissues induce granulomatous lesions that interfere with normal organ functions. Even though both the liver and the intestine are particularly susceptible to egg-induced tissue damage, little information is available on the pathobiochemical changes induced in these organs during infection. Using a mouse model, we investigated whether the lipid profiles of the liver and ileum were altered significantly as a result of infection. We found that triacylglycerol and cholesteryl ester levels decreased significantly as infection progressed.

Protein variation in the venom spat by the red spitting cobra, Naja pallida (Reptilia: Serpentes).

The venom spat by red spitting cobras (Naja pallida) was analyzed to document variations in protein composition occurring over short temporal periods (less than 5 min). These cobras exhibited distinct control of venom flow with spits averaging 1.7% of the volume of the venom gland, thus enabling the cobras to rapidly expel over 40 consecutive spits. Variations in the low and high molecular weight proteins were observed when comparing the 1st, 20th and 40th spits produced by the same specimens. The first few spits were characterized by a distinctive 9 kDa protein which was never observed beyond the 7th spit, was present in milked venom and was present when the spitting behavior was preceded by a 5 min period of induced defensive behaviors.

Thin-layer chromatography in food and agricultural analysis.

The TLC analysis of agricultural products, foods, beverages, and plant constituents is reviewed for the period from mid-1995 to mid-1999. Techniques and applications for a wide range of analyte and sample matrix types are covered, with specification of the particular layers, mobile phases, detection methods, and quantification conditions in many cases.

Effects of diet on the lipid composition of the digestive gland-gonad complex of Biomphalaria glabrata (Gastropoda) infected with larval Echinostoma caproni (Trematoda).

This study examined the effects of a larval Echinostoma caproni infection on the neutral lipid composition of the digestive gland-gonad complex (DGG) of Biomphalaria glabrata snails fed hen's egg yolk supplemented with lettuce (Y-L) or lettuce supplemented with Tetramin (L-T). Snails were experimentally infected with the miracidial stage of this echinostome, and their DGGs containing daughter rediae were analyzed for neutral lipids five weeks post-infection by qualitative and quantitative thin-layer chromatography. Light microscopy using Oil Red O (ORO) staining and transmission electron microscopy (TEM) were used to localize neutral lipids in the rediae. The DGGs of infected snails maintained on the Y-L diet showed a significant increase in free sterols and a significant decrease in triacylglycerols compared to uninfected snails maintained on the Y-L diet. The DGGs of infected snails maintained on the L-T diet showed no significant difference in free sterols or triacylglycerols compared to uninfected snails maintained on the L-T diet. ORO staining and TEM showed the presence of lipid droplets in rediae from snails on the Y-L diet. The significant decrease in triacylglycerols in the DGGs of infected snails maintained on the Y-L diet suggests that triacylglycerols were utilized by the rediae.

Neutral lipids in cercariae, encysted metacercariae, and rediae of Zygocotyle lunata.

High-performance thin-layer chromatography was used to analyze the neutral lipids in the rediae, cercariae, and encysted metacercariae of the paramphistomid trematode Zygocotyle lunata. Visual observations of the chromatograms showed that the most abundant lipid fractions were free sterols and free fatty acids in all larval stages and triacylglycerols in the metacercariae and rediae. The weight of free sterols (x +/- SE) was 120+/-20 ng/cercaria, 56+/-3.8 ng/redia, and 5.9+/-1.5 ng/encysted metacercaria; the weight of triacylglycerols was 13+/-0.88 ng/encysted metacercaria, 6.3+/-0.063 ng/redia, and was not detectable in the cercaria; the weight of free fatty acids was 160+/-17 ng/ cercaria, 76+/-9.1 ng/redia, and 4.2+/-0.46 ng/encysted metacercaria. Oil red O staining of whole larvae showed the presence of neutral lipids in the rediae but not in the cercariae or encysted metacercariae. A dramatic reduction was seen in the quantity of free sterols and free fatty acids in the encysted metacercariae as compared with the cercariae, suggesting that these neutral lipids are used in some way during the transformation from cercaria to metacercaria.

High performance thin-layer chromatographic analysis of sugars in Biomphalaria glabrata (Gastropoda) infected with Echinostoma caproni (Trematoda).

High performance thin-layer chromatographic analysis was done on the hemolymph and digestive gland-gonad complex (DGG) of Biomphalaria glabrata snails experimentally infected with the intramolluscan stages of Echinostoma caproni. The major sugars detected in both the DGG and hemolymph of infected and uninfected snails were glucose and trehalose. Quantitative analysis by scanning densitometry showed a significant reduction in glucose in both the hemolymph and DGG of infected snails at 4, 6, and 8 wk postinfection. A similar analysis on trehalose showed that this sugar was significantly reduced at 6 wk postinfection in the hemolymph and DGG of infected snails and could not be detected from these sites in infected snails by 8 wk postinfection. Findings from this study were compared with information on sugars in B. glabrata infected with larval stages of Schistosoma mansoni.

High-performance thin-layer chromatographic analysis of lutein and beta-carotene in Cerithidia californica (Gastropoda) infected with two species of larval trematodes.

High-performance thin-layer chromatography (HPTLC) analysis was done on lutein and beta-carotene in the digestive gland-gonad complex (DGG) and whole body of uninfected Cerithidia californica snails and those infected with the larval trematodes Mesostephanus appendiculatis or Euhaplorichis californiensis. HPTLC of the DGG extract on C-18 reversed-phase plates developed in petroleum ether-acetonitrile-methanol (1:2:2) mobile phase showed 2 identifiable pigment zones; the least polar zone had a retention factor (Rf) of 0.07, identical to a beta-carotene standard, and the more polar zone had an Rf of 0.41, identical to a lutein standard. Densitometric scanning of the pigment zones in sample versus standard chromatograms showed that the weight percent of lutein in the uninfected DGGs (3.4x10(-3)%) was significantly greater (P<0.05) than that of DGGs infected with either M. appendiculatis (0.35x10(-3)%) or E. californiensis (0.82x10(-3)%). Changes in beta-carotene in the infected DGGs were insignificant compared to the uninfected controls. However, the beta-carotene content of whole snails was significantly reduced (P<0.05) by infection with either trematode.

Effects of diet on the development of Schistosoma mansoni in Biomphalaria glabrata and on the neutral lipid content of the digestive gland-gonad complex of the snail.

In a previous study, when the snail Biomphalaria glabrata was infected with Schistosoma mansoni and maintained on a diet of hen's egg yolk, it produced fully developed cercariae in about one-half the time taken by snails fed Romaine lettuce. Increased lipids were also noted in the snails fed the yolk diet. The purpose of the present study was to further investigate nutritional effects of a high-lipid diet on larval schistosome development and to reexamine the time to cercarial patency in infected snails maintained on either the yolk or lettuce diet and to use high-performance thin-layer chromatography (HPTLC) to analyze the neutral lipids in the digestive gland-gonad complex (DGG) of snails maintained on both diets. Infected snails maintained at 26 C and fed either diet produced fully developed cercariae by 4 wk postinfection (PI). Likewise, infected snails maintained at 23 C and fed either diet produced fully developed cercariae by 6 wk PI. The contention that the yolk diet enhanced the time to cercarial patency was not confirmed. The HPTLC analysis of neutral lipids showed that the DGG of infected snails fed the yolk diet contained significantly greater amounts of free sterols and cholesteryl esters but not triacylglycerols than that of the infected snails fed the lettuce diet.

Recent advances in thin-layer chromatography of pesticides.

Advances in the applications of thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) for the separation, detection, and qualitative and quantitative determination of pesticides, other agrochemicals, and related compounds are reviewed for the period 1998-2000. Analyses are covered for a variety of samples, such as food, biological, and environmental, and for residues of pesticides of various types, including insecticides, herbicides, and fungicides, belonging to different chemical classes. References on formulation analysis, hydrophobicity studies, and the use of TLC and thin-layer radiochromatography (TLRC) for studies of pesticide metabolism, degradation, uptake, and related studies are also included.

Pesticide residue analysis (1999-2000): a review.

The literature of pesticide residue analysis is reviewed selectively for the period 1999-2000. Analyses of a wide range of pesticide classes and sample types, as well as some related organic pollutants, are covered. Studies of exposure and monitoring as well as pesticide degradation, persistance, leaching, mobility, and metabolism studies are included.