Solubilization and characterization of functionally coupled Escherichia coli heat-stable toxin receptors and particulate guanylate cyclase associated with the cytoskeleton compartment of intestinal membranes

• 1.1. Particulate guanylate cyclase and receptors for E. coli heat-stable enterotoxin were solubilized from the rat intestinal cytoskeletal compartment using Lubrol-PX and KC1.
• 2.2. Thirty to forty percent of the ST receptor and guanylate cyclase activities were extracted from the lipid layer with Lubrol-PX alone.
• 3.2. Seventy percent of the remaining activities were solubilized from the cytoskeleton with Lubrol-PX and KCl.
• 4.3. Guanylate cyclase solubilized from either compartment exhibited similar reaction kinetics.
• 5.4. Both high- and low-affinity classes of ST receptors were solubilized from the lipid and cytoskeleton compartments.
• 6.5. In the presence of ATPγS, ST selectively activated the guanylate cyclase solubilized from the cytoskeleton compared to that solubilized from the lipid bilayer.
• 7.6. Crosslinking experiments demonstrated a preferential solubilization of the 130 kDa receptor subunit from the cytoskeleton and the 56 kDa subunit from the lipid bilayer.
• 8.7. Development of a procedure to solubilize ST receptors and guanylate cyclase from the intestinal membrane cytoskeleton will permit purification and further detailed studies of the coupling of these activities.

     

Growth and haematological response of sturgeon hybrids Russian sturgeon (Acipenser guldenstadti brandt) × beluga (Huso huso L.) to protein and lipid contents in the diet

• 1.1. Fingerlings of intergenious hybrid Russian sturgeon (Acipenser guldenstadti) × beluga (Huso huso) weighing 22 g reared in water with salinity 18 ppt were fed nine diets differing in protein and fat content.
• 2.2. The increase of dietary protein content (from 45 to 52%) improved the fingerlings growth rate, food and protein conversion efficiencies. No effect of further protein content increase to 60% was observed.
• 3.3. The increase of dietary fat content from 10 to 20% positively influenced all growth results.
• 4.4. The muscular lipid content increased following the increase in dietary fat due to accumulation of triacylglycerols.
• 5.5. Distinctive leucopenia in neutrophils and leucophilia in lymphocytes following dietary protein and fat content increase were observed.
• 6.6. It was concluded that within the analysed range of values the increase of dietary protein and lipid content improved the physiological status of sturgeon hybrid fingerlings.

     

A lipid transfer particle in Musca domestica haemolymph

• 1.1. In Musca domestica haemolymph a lipid transfer particle (LTP) is present.
• 2.2. Musca domestica LTP is able to catalyze the transfer of lipids between different housefly lipophorin forms and also between lipophorins of Diptera and Lepidoptera.
• 3.3. The lipophorin of larval Dione juno (Lepidoptera) was purified and is composed of two apolipoproteins, apolipophorin I (M_{r = 209,000}) and apolipophorin II (M_{r = 85,000}) with a density of 1.124 g/ml.
• 4.4. The density of housefly lipophorin undergoes variations during the gonotrophic cycle.
• 5.5. The lipophorin density variation results suggest that when a high rate of lipid utilization occurs, the lipophorin has a higher density value.

     

Breeding and moulting fasts in macaroni penguins: Do birds exhaust their fat reserves?

• 1.1. Plasma concentrations of urea, uric acid and total lipid were compared in pre- and late-fast breeding and moulting macaroni penguins (Eudyptes chrysolophus) to test the hypothesis that birds exhaust their lipid reserves and initiate marked protein utilisation towards the end of natural fasts.
• 2.2. Male and female macaroni penguins fasted for a minimum of 29–32 days and 20 days during the breeding and moult fasts, and the difference in body weight over the sample period (reflecting body weight loss) was 31–34% and 41–47%, respectively.
• 3.3. There was no significant increase in plasma urea or uric acid at the end of either fast, nor any decrease in plasma lipid concentrations compared to pre-fast birds.
• 4.4. These results suggest that macaroni penguins continue to rely mainly on lipid reserves during the later stages of natural fasts. This is consistent with post-fast body composition data for other small penguin species.

     

Inhibitory effects of α- and β-carotene on croton oil-induced or enzymatic lipid peroxidation and hydroperoxide production in mouse skin epidermis

• 1.1. The effects of carotenes (α- and β-) on edema, MDA contents and peroxidizability ofcroton oil-treated mouse skin epidermis, hydroperoxide production and enzymatic lipid peroxidation of epidermal homogenates were studied. Edema was determined as ear punch weight and the intensity of lipid peroxidation was measured using malondialdehyde formation.
• 2.2. Carotenes (α- and β-) significantly suppressed edema formation, hydroperoxide production, lipid peroxidation caused by croton oil, Fe + 3-ADP/NADPH or paraquat/NADPH in vivo as well as in vitro.
• 3.3. These results indicate that both α- and β-carotene have chemopreventive effects on croton oil-induced tumor promotion in skin tumorigenesis by scavenging oxygen free radicals, indirectly determined as carotene inhibition of lipid peroxidation and hydroperoxide formation.

     

Comparative study on the fatty acid and lipid composition of four marine fish larvae

• 1.1. Fatty acid and lipid class composition were determined in larvae of four marine species: Atlantic halibut (Hippoglossus hippoglossus L.), plaice (Pleuronectes platessa), cod (Gadus morhua) and turbot (Scophthalmus maximus) at hatching and prior to first feeding.
• 2.2. Total fatty acid content decreased in the four species with up to 50% reduction in one of the halibut groups. Docosahexanaoic acid (22:6 n-3) was especially utilized.
• 3.3. Low lipid utilization was found in turbot in relation to the other three species.
• 4.4. Water environmental temperature may explain some of the differences in the fatty acid utilization and the source of metabolic energy between cold water species (halibut, cod, and plaice) and temperate species (turbot), in the period from hatching to prior to first feeding.
• 5.5. Relative amounts of neutral lipids and phospholipids were similar in plaice, cod and halibut, approximately 25% and 75% of total lipids, respectively, and were approximately constant during the yolk-sac stage. Neutral lipids were dominant for turbot at hatching, accounting for 53–55% of the total lipids, while phospholipids predominated prior to first feeding, being 56–59%.
• 6.6. Phosphatidylcholine was catabolized in halibut, plaice and cod but not in turbot, while phosphatidylethanolamine tended to be synthesized in all four species.

     

Changes in the phospholipid composition and in fatty acids of phosphatidylcholine and phosphatidylethanolamine of various tissues of the developing tadpole of Agalychnis dacnicolor

• 1.1. Lipid changes occur in the developing tadpole of A. dacnicolor. The phosphatidylcholine content of liver and tail decrease during metamorphosis.
• 2.2. In liver, the fatty acids of phosphatidylcholine and phosphatidylethanolamine become more unsaturated.
• 3.3. In skin, phosphatidylcholine becomes more unsaturated and phosphatidylethanolamine becomes more saturated.
• 4.4. In tail, phosphatidylcholine becomes more saturated and phosphatidylethanolamine shows no change.
• 5.5. Triglycerides become more unsaturated in skin but become more saturated in tail.

     

Water diffusion,ion transport and lipid composition of the skin of Rana cyanophlyctis Schneider under osmotic stress

• 1.1. Analysis of the total lipid content (TL), components of the neutral lipid fraction (NLF), phospholipid fraction (PLF), recordings of electrical potential differences and diffusional permeability were carried out in the skin of the aquatic frog Rana cyanophlyctis subjected to in vivo salt stress (0.9 sodium chloride) for different durations (0, 1, 3 and 7 days).
• 2.2. A general decrease of skin TL and of components of the NEE and PEE was observed.
• 3.3. Stoichiometric ratios for skin PLF components under initial salt stress of different durations reveal an increase of the ratios of sphingomyelin and phosphatidyl choline after osmotic stress.
• 4.4. The diffusional permeability of water increased following exposure to salt stress of I, 3 and 7 days duration.
• 5.5. The transepithelial potential difference measured in vitro after a salt stress of 3 days was considerably higher than the controls.

     

Seasonal changes of total lipids in the turtle Sternotherus odoratus

• 1.1. Seasonal variation in total lipids was examined in several body components of the turtle Sternotherus odoratus.
• 2.2. Carcass fat stores in both sexes were depleted during winter. Additionally, a decline in carcass lipids was associated with increases in gonadal mass.
• 3.3. Concentrations of liver lipids were maximal during August and minimal during winter.
• 4.4. Males showed little seasonal change in plasma lipid levels, whereas females had seasonal peaks temporally associated with ovarian development and carcass fat storage.
• 5.5. Ovarian concentrations of lipids were minimal after nesting and increased during fall.
• 6.6. Results suggest that S. odoratus uses stored fats both for reproduction and maintenance during winter.

     

Social facilitation of reduced oxygen consumption in Mus musculus and Meriones unguiculatus

• 1.1. The short-term resting rates of oxygen consumption of laboratory white mice (Mus musculus) and Mongolian gerbils (Meriones unguiculatus) were measured by closed system manometry.
• 2.2. Metabolic rates of animals tested individually were compared to those of huddled trios and trios in which the animals were tested simultaneously but prevented from physical contact (separated trios) at temperatures ranging from 9–25° C.
• 3.3. Rates of increase of weight-specific resting metabolism were greatest for animals tested individually.
• 4.4. There was no significant difference in the rates of increase of oxygen consumption between huddled and separated trios in cither species.

     

Biochemical aspects of Balanus hameri haemolymph,together with some comparative haemolymph data for Balanus balanus and Lepas anatifera

• 1.1. The concentration of protein in the haemolymph of Balanus hameri ranged from 2.0 to 17.3 mg/ml, and the lipid from 1.4 to 7.7 mg/ml; the haemolymph protein and lipid levels increased significantly prior to cross-fertilization.
• 2.2. The protein and lipid concentrations in Balanus balanus haemolymph were 8.1 and 1.7 mg/ml respectively.
• 3.3. The lipid concentration of Lepas anatifera haemolymph was 1.2 mg/ml.
• 4.4. The neutral lipid and phospholipid components of B. hameri and L. anatifera haemolymph were the same, with the major components of the phospholipid fraction being phosphatidyl ethanolamine and phosphatidyl choline.
• 5.5. The osmolarity (970.4 mOsm), chloride ion concentration (501.3 m-eq/l) and pH (7.29) of B. hameri haemolymph were also determined.

     

Time-dependent cadmium-neurotoxicity in rat brain synaptosomal plasma membranes

• 1.1. The modulation of lipid dynamics and lipid protein interactions were studied in rat brain synaptosomal plasma membranes (SPM) up to 24 hr after exposure to cadmium (Cd).
• 2.2. The activity of acetylcholinesterase and adenylate cyclase showed a considerable decrease after 6 hr of Cd exposure, followed by a progressive increase up to 24 hr.
• 3.3. SPM chemiluminescence showed a maximum decrease at 12 hr, demonstrating a considerable increase in lipid peroxidation.
• 4.4. SPM of Cd-exposed animals showed a statistical significant increase in fluorescence anisotropy parameter [(r₀/r) — 1]⁻¹ at 18 and 24 hr compared to SPM of the control, indicating a decrease of membrane fluidity.

     

Characterization of lactoferrin binding to the MAC-T bovine mammary epithelial cell line using a biotin-avidin technique

• 1.1. A non-radioisotopic method utilizing a biotin-avidin approach was used to characterize lactoferrin binding to the clonal MAC-T bovine mammary epithelial cell line.
• 2.2. Binding of lactoferrin to MAC-T cells and isolated membranes was specific and saturable.
• 3.3. Unlabeled lactoferrin competed for and displaced biotin-labeled lactoferrin from binding sites on mammary epithelial cells. In contrast, unlabeled transferrin did not compete.
• 4.4. Scatchard analysis of lactoferrin binding to MAC-T cell crude membranes was nonlinear, revealing two classes of binding sites with association constants (K_a) of 2.36 × 10⁷ and 3.36 × 10⁶M⁻¹.
• 5.5. Binding of lactoferrin to MAC-T cells may be associated with the initial events which result in decreased MAC-T cell proliferation.

     

Measurement of blood flow in the skin and oral mucosa of the rhesus monkey (Macaca mulatta) using laser doppler flowmetry

• 1.1. It is generally assumed that oral blood flow is higher than that of skin, and invasive methods to measure blood flow support this view.
• 2.2. However, it was not known whether this finding would be confirmed by laser Doppler flowmetry, which is a noninvasive method to measure blood flow.
• 3.3. The purpose of this study was to compare blood flow in oral and skin regions of the rhesus monkey using laser Doppler flowmetry.
• 4.4. The results demonstrated that blood flow was significantly higher in oral regions as compared to facial skin (P < 0.05).
• 5.5. This finding is most likely related to the more abundant capillary supply in oral mucosa as compared to skin.

     

Characterization of Colorado potato beetle lipophorin: A hydrocarbon-rich diacylgycerol-poor lipophorin

• 1.1. The lipid composition of lipophorin from the Colorado potato beetle, Leptinotarsa decemlineata Say, was analyzed.
• 2.2. This insect lipophorin contains 44% lipid and is characterized by large amounts of hydrocarbons and small amounts of diacylglycerol.
• 3.3. This is the first observation of a diacylglycerol-poor insect lipophorin in haemolymph.
• 4.4. Since the main energy source for flight in the Colorado potato beetle is proline, the low diacylglycerol content in lipophorin must be related to its peculiar flight metabolism.
• 5.5. This lipophorin, however, can still take up appreciable amounts of diacylglycerol from the locust fat body. Hydrocarbon uptake by this lipophorin was also demonstrated.
• 6.6. The main function of this lipophorin therefore seems to be transport of hydrocarbons from oenocytes to the cuticle.

     

Entomopathogenic fungal infection (Deuteromycotina: Hyphomycetes) affects water relations of the german cockroach,Blattella germanica (L.) (Dictyoptera: Blattellidae)

• 1.1. The total body water, lipid content, and cuticular permeability of fungus infected and uninfected German cockroaches, Blattella germanica, were examined.
• 2.2. Infected adult cockroaches weighed less and had significantly more body water than did uninfected specimens of the same size.
• 3.3. Uninfected medium-size nymphs weighed significantly more than infected nymphs, but there was no difference in body size between infected and uninfected small nymphs.
• 4.4. Cuticular permeability and lipid content of infected and uninfected cockroaches was not significantly different.
• 5.5. Sequestering of water by the fungal cells is discussed as a possible factor in the pathology of this fungal parasite.

     

Comparison of minerals in milk of four species

• 1.1. Milk samples of 4 ml or more were obtained from guinea pigs (Cavia porcellus), dairy cattle (Bos taurus), horses (Equus caballus) and humans (Homo sapiens). The milks were analysed for minerals including calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K) and sodium (Na) by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES).
• 2.2. Calcium was approximately twice as concentrated in guinea pig milk as in cows' milk, which was twice as much as the level in mares' milk, and this, in turn, was twice as concentrated as human milk.
• 3.3. The ratio of Ca to P in guinea pig milk was 1.66:1, while it was 1.24:1 in cows' milk, 1.56:1 in mares' milk and 2.07:1 in human milk.
• 4.4. Potassium was the most abundant mineral in the milks of cows, mares and humans, but not in guinea pig milk, and was much higher in cows' milk than in others.
• 5.5. Sodium was highest in guinea pig milk with cows' milk being a close second.
• 6.6. Magnesium was one-tenth as concentrated as Ca.

     

Lipid components and utilization in consumers of a seagrass community: An indication of carbon source

• 1.1. The lipid components of three animals, the rock crab Nectocarcinus integrifons, the rock flathead Platycephalus laevigatus and the southern garfish Hyporhamphus melanochir, feeding in the seagrass beds at Corner Inlet, Victoria, Australia have been examined in detail in order to provide further information on seagrass community structure.
• 2.2. Biological marker compounds detected within animal gut content material were used to recognize dietary sources and then utilized by community members.
• 3.3. Both H. melanochir and N. integrifons have been shown to ingest and to varying degrees incorporate seagrass lipid material, thus further confirming the importance of seagrass carbon in the Corner Inlet environment.
• 4.4. The southern sea garfish H. melanochir is observed to remove C₁₈ PUFAs (polyunsaturated fatty acids) from ingested seagrass material.
• 5.5. Seagrass sterols are altered during incorporation into the lipids of this fish.
• 6.6. Lipid-rich digestive juices play a role in the digestive processes of all three animals.
• 7.7. Components tentatively identified as (NMI) (non-methylene interrupted) fatty acids have been detected in the lipids of the garfish H. melanochir and the crab N. integrifons.
• 8.8. The fecal material of all three animals represent possible sources of these lipids (NMI acids) in Corner Inlet sediments.
• 9.9. Based on lipid compositional data, N. integrifons feeds on Posidonia australis detritus and associated epiphyte material.
• 10.10. The removal of both plant and epibiota cellular lipids along the digestive tract of the crab was observed, although structural components such as long chain mono- and α,ω-dicarboxylic acids, which have been previously recognized as seagrass marker lipids are not directly absorbed.

     

Biochemical and calorific content of deep-sea aspidochirotid holothurians from the northeast atlantic ocean

• 1.1. The organic composition of the body tissues of eight species of deep-sea aspidochirotid holothurian, collected between 500 and 4100m depth in the NE Atlantic Ocean, was obtained by the biochemical analysis of protein, lipid, carbohydrate and % ash.
• 2.2. The major organic class was protein with soluble lipid the major soluble fraction in the ovary. Carbohydrate values were consistently low.
• 3.3. The calorific value was significantly higher in the ovary than in the other tissues.
• 4.4. The total body calorific content for two selected species, Benthothuria funebris and Mesothuria lactea, was 25.62 and 26.24J/mg ash-free dry weight (AFDW).

     

Lipid composition of three geographical sources of brine shrimp nauplii (Artemia sp.)

• 1.1. Percentage of triacylglycerols (TG), free fatty acids (FFA) and phospholipids (PL) in the total lipids, the fatty acid composition of each of these lipid classes, and the percentage of cholesterol were determined by gas chromatography in three geographical sources (San Francisco Bay, SFB; Chinese, CH; Colombian, COL) of brine shrim (Artemia sp.) nauplii.
• 2.2. There were no significant differences among sources of brine shrimp in total lipids, TG or FFA with means for all sources of 17.8, 65.8 and 10.9%, respectively. Percentage of phospholipid was significantly higher in SFB and CH sources of brine shrimp, 25.1 and 26.5%, respectively, than in COL 18.3%.
• 3.3. Marked differences in percentages of 18:3 (n-3) (linolenic acid) and 20:5 (n-3) (eicosapentaenoic acid or EPA) were found among brine shrimp sources, and concentration of these two fatty acids were usually inversely related within sources. The CH source contained higher concentrations of EPA ( > 9.0%) than the COL and SFB sources (< 5.0%) in all three lipid classes analyzed. No 22:6 (n-3) (docosahexaenoic acid or DHA) was found in any brine shrimp source.
• 4.4. Fatty acid compositions of the TG and PL were similar and did not differ among sources of brine shrimp, while the FFA had a lower percentage of polyunsaturated fatty acids, but was similar among sources of brine shrimp.
• 5.5. Differences in n-3 fatty acid composition indicated a difference in nutritional quality among sources of brine shrimp for feeding larval fish.