Reversal of dietary-induced hyperlipidemia in Biomphalaria glabrata (Gastropoda).

1. To determine if dietary induced hyperlipidemia in snails could be reversed, thin-layer chromatography studies were done on lipids in the digestive gland-gonad (DGG) complex of Biomphalaria glabrata fed either hen's egg yolk for 2 weeks (Group A), yolk for 1 week followed by leaf lettuce for 1 week (Group B), or lettuce for 2 weeks (Group C). 2. The major lipid fractions in Group A were triacylglycerols, phosphatidylethanolamine, and phosphatidylcholine, along with lesser amounts of sterol esters, methyl esters, free fatty acids, free sterols and unidentified phospholipids. 3. Groups B and C had about one-half the amount of triacylglycerols than Group A and did not show sterol esters or methyl esters. 4. The triacylglycerol increase of the DGG resulting from the hen's egg diet could be reversed by returning the snails to the lettuce diet.     

Effects of diet and larval trematode parasitism on lutein and beta-carotene concentrations in planorbid snails as determined by quantitative high performance reversed phase thin layer chromatography

High performance thin layer chromatography (HPTLC) was used to quantify the concentrations of beta-carotene and lutein in Biomphalaria glabrata and Helisoma trivolvis (Colorado and Pennsylvania strains) snails under various conditions. These conditions were: snails fed a lettuce (L) vs. a yolk (Y) diet; B. glabrata infected with Echinostoma caproni vs. uninfected snails; and H. trivolvis (PA) infected with Echinostoma trivolvis vs. uninfected snails. The pigments were extracted from the snail whole bodies and digestive gland-gonad complexes, separated by reversed phase HPTLC, and quantified by densitometric scanning with standard calibration curves. Snails on the L-diet showed significant increases (Student's t-test, P<0.05) in the concentrations of beta-carotene and lutein compared to snails on the Y-diet. Snails infected with echinostomes showed no significant differences (Student's t-test, P>0.05) in the concentrations of lutein and beta-carotene compared to the uninfected cohorts. Our results were compared with previous studies that analyzed beta-carotene and lutein in snails infected with larval trematodes. Variations in the results of our study compared with others reflect intrinsic differences in the larval trematode-snail systems used.     

Sterols in the plasma and digestive gland-gonad complex of Biomphalaria glabrata snails, fed lettuce versus hen's egg yolk, as determined by GLC

1. Gas-liquid chromatography studies were done on sterols in plasma and the digestive gland-gonad (DGG) complex of Biomphalaria glabrata snails fed lettuce vs hen's egg yolk. 2. The major sterols present in the DGG of both populations were cholesterol, stigmasterol, beta-sitosterol, campesterol, and desmosterol. 3. The percentage composition of cholesterol in the DGG of yolk vs lettuce fed snails was 82 and 51, respectively. 4. The elution profiles of sterols in the plasma of yolk vs lettuce fed snails were similar; both contained desmosterol, campesterol, and stigmasterol, negligible amounts of cholesterol, and unidentified sterols. 5. The high lipid diet increased the level of cholesterol in the DGG but not in the plasma.     

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.     

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.     

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.     

Physiologic studies of snail-schistosome interactions and potential for improvement of in vitro culture of schistosomes

Summary Despite extensive efforts to develop suitable media for rearing the intramolluscan stages of schistosomes, successful in vitro culture of these parasites remains elusive. Recent³¹P NMR studies demonstrated that the levels of free phospholipids, particularly phosphatidylcholine, in the digestive gland of the snail,Biomphalaria glabrata, were dramatically reduced when the host was infected withSchistosoma mansoni. It was speculated that absorption of host phosphatides may be an important source of membrane phospholipid precursors and fatty acids for developing sporocysts and cercariae. During the present investigations,B. glabrata was maintained on a high fat diet of egg yolk, and the lipid composition of control uninfected and infected snails examined by³¹P and¹³C NMR. In addition, the levels of host hemolymph metabolites, including glucose and urea, considered as indicators of parasite nutrient uptake, were monitored. The lipid level of snails fed egg yolk was greatly increased, and hosts developed patent infections in approximately half the time of infected snails maintained on lettuce. The composition of the free phospholipids accumulated in the tissues ofB. glabrata fed egg yolk were the same as those previously reported in the cercarial stage ofS. mansoni. Moreover, the fatty acids ofS. mansoni and those reported here in the neutral lipids and free phosphatides in the host tissues were similar. Uninfected snails maintained on lettuce had higher hemolymph levels of glucose than those reared on egg yolk, and infected hosts on egg yolk had significantly lower levels of hemolymph urea. β-hydroxybutyrate was the principal hemolymph metabolite in snails fed egg yolk, but was not detected in snails maintained on lettuce. The level of β-hydroxybutyrate in the hemolymph of snails on egg yolk was significantly reduced by infection. The results indicated that the pattern of host hemolymph nutrient utilization by larval schistosomes may be markedly altered by host diet, and it was concluded that host lipids may directly and indirectly be important nutrients for developing schistosomes. Future studies on in vitro culture of the intramolluscan stages of schistosomes should emphasize the potential role of lipids and attempt to define the nutritive value of those medium components that presently supply lipids in culture media, most notably serum.     

Effects of snail size and diet on encystment of Echinostoma caproni cercariae in juvenile Helisoma trivolvis (Colorado strain) and observations on survival of infected snails

The effects of snail size and diet on encystment of Echinostoma caproni cercariae in juvenile Helisoma trivolvis (Colorado strain) snails were studied. Encystment in neonatal (<1-mm shell diameter) and juvenile (2- to 3-mm shell diameter) snails was compared 24 hr postinfection (PI) after individual exposure of snails of each size to 1, 5, 10, 25, or 50 cercariae. Significantly more cysts were recovered from juvenile snails exposed to 10, 25, or 50 cercariae than from neonatals with comparable exposure. The maximum number of cysts recovered from juveniles exposed to 50 cercariae was 42, compared with a maximum of 15 cysts in neonatals comparably exposed. Size of H. trivolvis was a major factor in determining cyst burden in this planorbid. A diet of either Romaine lettuce leaf or hen's egg yolk did not have a significant effect on the number of cysts recovered at 24 hr PI from juvenile snails exposed to 25 or 75 cercariae. Survival of infected versus uninfected neonatals was also examined for 7 days. Neonatals exposed to 10 cercariae showed a significant decrease in survival at 6 and 7 days PI when compared with uninfected controls.     

An evaluation of purification methods for baculoviruses

In Biomphalaria glabrata parasitized by Schistosoma mansoni there was an increase in relative weight of the digestive gland-gonad complex and a decrease in glycogen in that complex and in the remainder of the carcass by day 25. Glycogen levels further decreased close to zero and remained at this low level for the duration of the experiment. Relative weight of the digestive gland-gonad reached a peak at day 30 and decreased toward normal by day 40. Galactogen levels in the albumen gland, although decreased slightly, were not significantly lower than in normal snails. In starved snails, glycogen and galactogen decreased significantly below normal at day 21 and remained at a low level until the experiment ended. This study raises the possibility that starvation of the host by the parasite may play a significant role in the pathology observed in this infection.     

Interaction of photoperiod and nutritive state in female reproduction of Lymnaea stagnalis

Summary

A study was made of the interaction of the photoperiod and the availability of food in influencing egg laying of the freshwater snail Lymnaea stagnalis. At a long day photoperiod (LD = 16 h light/8 h dark) egg laying of fed snails had increased compared with that of fed animals kept at a medium day photoperiod (MD = 12 h light/12 h dark). In MD snails oviposition ceased within a week of the beginning of a starvation period. This is most probably due to a reduction in the activities of the neuroendocrine caudodorsal cells which secrete an ovulation hormone. In contrast, in starved LD snails a low rate of ovipository activity continued, indicating that a lowered frequency of caudodorsal cell release cycles occurred under these conditions. The decreased mean size (number of eggs) of the egg masses in starved LD snails indicates that the activities of the endocrine dorsal bodies, which control vitellogenesis and synthetic activities in the female accessory sex organs, had decreased.

All MD snails survived, but nearly all LD snails died during the course of the experiment. Determinations of the mantle glycogen stores of LD snails suggest that the high mortality of LD snails is due to exhaustion of the animal's energy reserves.     

Effects of aestivation and starvation on the neutral lipid and phospholipid content of Biomphalaria glabrata infected with Schistosoma mansoni

The effects of aestivation or starvation on the neutral lipid and phospholipid content of Biomphalaria glabrata patently infected with Schistosoma mansoni were determined by high-performance thin-layer chromatography-densitometry. Infected-aestivated snails were maintained in a moist chamber at 24 +/- 1 C and a relative humidity of 98 +/- 1%. Infected-starved snails were maintained in artificial spring water (ASW) at 23 +/- 1 C without exogenous food. Infected snails (the controls) were maintained in ASW at 23 +/- 1 C and fed lettuce ad libitum. The 3 groups were maintained in the laboratory for 7 days, and then the lipids from the digestive gland-gonad complex (DGG) were extracted and analyzed by class. Infected-aestivated snails exhibited greater mortality rate and weight loss after 7 days than did the infected-starved snails. The steryl ester concentration in the infected-starved snails was significantly increased (P = 0.010) compared with the controls but not compared with infected-aestivated snails; the concentration of phosphatidylcholine in infected-aestivated snails was significantly decreased (P = 0.007) compared with the controls but not when compared with the infected-starved snails. Aestivation or starvation had a significant effect on the concentration of certain lipid classes in the DGG of B. glabrata infected with S. mansoni.     

31P NMR studies on adenylates and other phosphorus metabolites in the schistosome vector Biomphalaria glabrata

31P nuclear magnetic resonance spectroscopy was applied successfully to whole intact and de-shelled snails and to the isolated digestive gland-gonad tissue complex as well as other tissues of Biomphalaria glabrata. Several phosphorus metabolites, including ATP and ADP, were observed. The mean ATP/ADP ratio calculated for the tissue complex was 3.1 and the ATP concentration was 0.73 nmoles/mg tissue fresh weight. Assignments for AMP, sugar phosphates, and inorganic phosphate peaks were tentatively made. A major phosphorus component was identified as a phosphonate and this metabolite was also present in egg masses and the albumin gland. Phosphoarginine was not observed in the tissue complex but was present in whole animals. Infection by Schistosoma mansoni resulted in marked alteration in the relative levels of phosphorus metabolites in the digestive gland-gonad complex during the course of infection. The decrease in phosphonate was particularly notable. The relative level of a metabolite occurring at -1.1 ppm was also decreased but its identity remained unknown. The ATP/ADP ratio was not affected by infection, but an increase in the relative level of inorganic phosphate suggested a possible decrease in phosphorylation potential.     

Rapid modulation of the n-3 docosahexaenoic acid levels in the brain and retina of the newly hatched chick

The newly hatched chick obtains its fatty acids almost completely from the lipids of the egg yolk as these are transferred to the developing embryo during its 21-day period of incubation. Since the diet of the laying hen greatly influences the fatty acid composition of the egg lipids, and presumably also the fatty acid composition of the resulting chick, we tested how quickly and to what extent varying the amount of n-3 fatty acids in the diet of the hen would modulate the level of n-3 fatty acids in the brain and retina of the newly hatched chick. White Leghorn hens were fed commercial or semi-purified diets supplemented with 10% fish oil, linseed oil, soy oil, or safflower oil. Eggs, together with the brain, retina, and serum of newly hatched chicks, were then analyzed for fatty acid composition. The fatty acids of egg yolk responded quickly to the hen's diet with most of the change occurring by 4 weeks. There was a linear relationship between the linolenic acid content of the diets and levels of this fatty acid in egg yolk and chick serum. In chicks from hens fed the fish oil diet, the total n-3 fatty acids, including 22:6(n-3), were elevated twofold in the brain and retina and sevenfold in serum relative to commercial diet controls. The safflower oil diet led to a very low n-3 fatty acid content in egg yolks and only 25% of the control n-3 fatty acid content in the brain and retina of chicks.(ABSTRACT TRUNCATED AT 250 WORDS)     

14C uptake by Schistosoma mansoni from Biomphalaria glabrata exposed to 14C-glucose

Exposure of Biomphalaria glabrata infected with Schistosoma mansoni to ¹⁴C-glucose results in a greater uptake of original total snail label by the parasitized digestive gland-gonad, site of the developing daughter sporocysts and cercariae, than by the digestive gland-gonad of control animals. As a consequence of this greater uptake by the infected digestive gland-gonad, the albumen gland and remainder of the carcass of parasitized snails receive less label than do those areas in normal snails. Emergence of cercariae from the snail and daughter sporocyst mass account for a diversion of 12.6% of original total label from the infected snail itself. This diversion of label from the snail to the parasite may explain carbohydrate depletion in parasitized snails.     

Diet alters delayed selfing,inbreeding depression,and reproductive senescence in a freshwater snail

Reproductive success is a critical fitness attribute that is directly influenced by resource availability. Here, we investigate the effects of diet‐based resource availability on three interrelated aspects of reproductive success: a change in mating system based on mate availability, consequent inbreeding depression, and the deterioration of reproductive efficiency with age (senescence). We employed a factorial experimental design using 22 full‐sib families of the hermaphroditic freshwater snail Physa acuta to explore these interactions. Individual snails were reared in one of two mate‐availability treatments (isolated [selfing] or occasionally paired [outcrossing]) and one of two diet treatments (boiled lettuce or Spirulina, an algae that is rich in protein, vitamins, and minerals). Spirulina‐fed snails initiated reproduction at a 13% earlier age and 7% larger size than lettuce‐fed snails. Spirulina also resulted in a 30% reduction in the time delay before selfing. Compared to lettuce, a diet of Spirulina increased inbreeding depression by 52% for egg hatching rate and 64% for posthatching juvenile survival. Furthermore, Spirulina led to a 15‐fold increase in the rate of reproductive senescence compared with a diet of lettuce. These transgenerational, interactive effects of diet on inbreeding depression and reproductive senescence are discussed in the context of diet‐induced phenotypic plasticity.     

Effects of Dietary Form of Selenium on Its Distribution in Eggs

The objective of this experiment was to investigate the selenium distribution in eggs from hens fed diets supplemented with Se from sodium selenite (SS) or selenium-enriched yeast (SY). One-day-old female chickens of Hy-Line Brown breed were randomly divided into four groups according to dietary treatments and, for the subsequent 9?months, were fed diets which differed only in the form or amount of Se supplemented. During the whole experiment, group 1 (control) was fed basal diet (BD) with only background Se level of 0.13?mg/kg dry matter (DM). Diets for groups 2 and 3 consisted of BD supplemented with an Se dose of 0.4?mg/kg DM either in the form of SS or SY, respectively. Group 4 was fed BD supplemented with 0.9?mg Se/kg DM from SY. After 9?months of dietary treatments, the Se levels in egg yolk and albumen from hens fed unsupplemented diet were almost identical whereas eggs from hens given diet supplemented with SS showed significantly higher Se deposition in yolk than in albumen (P?相似文献   

Selenium Concentrations in Tissues and Eggs of Growing and Laying Chickens Fed Sodium Selenite at Different Levels

Growing and laying chickens were fed graded levels of selenium in the form of sodium selenite. One day old Norwegian bred broiler chickens and 20 weeks old Norwegian bred White Leghorn chickens were divided into 5 groups each and fed a basal diet supplemented with 0, 0.1, 1.0, 3.0 or 6.0 μg Se/g for 6 and 31 weeks, respectively. At the end of the experiments significantly higher concentrations of selenium were found in the groups fed 1.0, 3.0 and 6.0 μg Se/g diet compared to the control group. Correspondingly higher concentrations of selenium were found in egg samples. The increase in egg yolk selenium was much higher than in egg white. Significant correlations were found between the amounts of selenium added to the ration and the selenium concentrations in liver, kidney, breast muscle, egg white, yolk and homogenized egg. There were no differences in body weight gain and egg production between the groups. A possible positive contribution to animal and human health of selenium supplementation of animals’ diet above the required level is discussed.     

Antioxidant systems of the developing quail embryo are compromised by mycotoxin aurofusarin

The effects of aurofusarin in the quail diet on the antioxidant systems of the developing embryo are investigated. Thirty eight 45-day-old Japanese quails (Coturnix japonica) were divided into two groups and were fed on a corn-soya diet or the same diet supplemented with aurofusarin at the level of 26.4 mg/kg feed in the form of Fusarium graminearum culture enriched with aurofusarin. Eggs obtained after 7 weeks of feeding were incubated. Samples of quail tissues were collected at day 17 of embryonic development and from day old hatchlings. Antioxidants and malondialdehyde were analysed by HPLC-based methods. Inclusion of aurofusarin in the maternal diet was associated with decreased concentrations of alpha- and gamma-tocopherols, alpha- and gamma-tocotrienols, retinol, lutein and zeaxanthin in egg yolk. The vitamin E (tocopherols and tocotrienols) concentration in the liver and yolk sac membrane (YSM) of the day 17 embryos and the hatchlings from aurofusarin-fed group was significantly decreased. Alpha-tocopherol concentration was also reduced in kidney, lung, heart, muscle and brain of day-old quails. In the liver of day-old quails, concentrations of lutein, zeaxanthin, retinol, retinyl linoleate, retinyl oleate, retinyl palmitate and retinyl stearate were also reduced. As a result of these diminished antioxidant concentrations, tissue susceptibility to lipid peroxidation was significantly increased. It is suggested that a compromised antioxidant system of the egg yolk and embryonic tissues could predispose quails to increased mortality at late stages of their embryonic development.     

Ultrastructural localization of esterase and acid phosphatase in digestive gland cells of fed and starvedCepaea nemoralis (L.) (Mollusca: Helicidae)

Summary The ultrastructural localizations of thiolacetic acid esterase, indoxyl acetate esterase and acid -glycerophosphatase have been studied in the digestive gland cells of fed and starvedCepaea nemoralis. In fed snails the major localization of all three enzymes was in the green granule vacuoles of digestive cells. In addition, the cytoplasm of calcium cells and the Golgi apparatus and GERL (?) of all cell types were acid phosphatase positive. Many digestive cells of starved snails showed a similar enzyme distribution to that found in fed snails but other digestive cells showed a very high cytoplasmic activity of all three enzymes. It is suggested that these cells are in the process of autolysis. New light is also thrown on the process by which food is transported from the digestive gland lumen to the phagosomes of digestive cells.     

The fatty acid composition of oophagous tadpoles (Chirixalus eiffingeri) fed conspecific or chicken egg yolk

We compared the lipid content and fatty acid composition of (1) the egg yolk of three anuran species (Chirixalus eiffingeri, Rhacophorus moltrechti and Buergeria robustus) and chicken eggs; and (2) C. eiffingeri tadpoles fed conspecific eggs or chicken egg yolk. Anuran and chicken egg yolk contained more non-polar than polar lipids but the proportions varied among species. Chicken egg yolk contained low amounts of 22:5n-3 in the polar lipid fraction, and B. robustus eggs did not contain any n-3 or n-6 non-polar lipids. The specific variation of lipid contents and fatty acid composition may relate to the maternal diet and/or breeding biology. In C. eiffingeri tadpoles that fed chicken yolk or frog egg yolk, the dominant components of polar and non-polar lipids were 16:0, 18:0, 18:1, and 18:2n-6, or 20:4n-6 fatty acids. C. eiffingeri eggs contained more n-3 fatty acids (e.g. 18:3n-3 and 20:5n-3) than chicken egg yolk, and tadpoles fed conspecific eggs contained more of these fatty acids than tadpoles fed chicken egg yolk. The compositional differences in the fatty acids between C. eiffingeri tadpoles that fed frog egg or chicken egg yolk are the reflection of the variation in the dietary sources. Our results suggest a direct incorporation of fatty acids into the body without or minimal modification, which provide an important insight into the physiological aspects of cannibalism.