Small Amounts Of Lipids Research Articles

Inhibitory Effect of Polypeptides Produced by Brevibacillus brevis on Ochratoxigenic Fungi in the Process of Pile-Fermentation of Post-Fermented Tea

Contamination by ochratoxigenic fungi and its prevention during the pile-fermentation of post-fermented tea have always been a concern. The present study aimed to elucidate the anti-fungal effect and mechanism of polypeptides produced by B. brevis DTM05 (isolated from post-fermented tea) on ochratoxigenic fungi, and to to evaluate their use in the pile-fermentation process of post-fermented tea. The results showed that polypeptides (produced by B. brevis DTM05) with a strong antifungal effect against A. carbonarius H9 mainly had a molecular weight between 3 and 5 kDa. The Fourier-transform infrared spectra of this polypeptide extract showed that it was a mixture consisting mainly of polypeptides and small amounts of lipids and other carbohydrates. The polypeptide extracts significantly inhibited the growth of A. carbonarius H9, and its minimum inhibitory concentration (MIC) was 1.6 mg/L, which significantly reduced the survival rate of spores. The polypeptides also effectively controlled the occurrence and ochratoxin A (OTA) production of A. carbonarius H9 on the tea matrix. The lowest concentration of polypeptides that significantly inhibited the growth of A. carbonarius H9 on the tea matrix was 3.2 mg/L. The enhancement of the fluorescence staining signal in the mycelium and conidiospore showed that the polypeptides with a concentration of more than 1.6 mg/L increased the permeability of the mycelium membrane and conidial membrane of A. carbonarius H9. The significant increase in the extracellular conductivity of mycelia suggested the outward leakage of intracellular active substances, and also further indicated an increase in cell membrane permeability. Polypeptides with a concentration of 6.4 mg/L significantly down-regulated the expression level of the polyketide synthase gene related to OTA production (acpks) in A. carbonarius H9, which may be the fundamental reason why polypeptides affect OTA production. In conclusion, reasonable use of the polypeptides produced by B. brevis can destroy the structural integrity of the cell membrane, make the intracellular active substances leak outward, accelerate the death of fungal cells and down-regulate the expression level of the polyketide synthase gene in A. carbonarius; thus, they can effectively control the contamination of ochratoxigenic fungi and OTA production during the pile-fermentation of the post-fermented tea.

Nutritional Value, Bioactive Components and Antioxidant Activity of Schisandra chinensis (Turcz.) Baill. Leaves

As a part of the ongoing interest in the nutritional and antioxidative properties of a little-known East Asian plant species, the aim of the study was to determine the contents of macronutrients and selected elements, profiles of fatty and amino acids, the content of phenolic compounds, β-carotene, vitamin A and E, and antioxidant activity of Schisandra chinensis (Turcz.) Baill. edible leaves. Schisandra chinensis leaves contained a small amount of lipids – 4.36 % and 12.38 % of proteins. Sugars (fructose, maltose, sucrose, and lactose) were detected only in trace amounts (<0.5 g/kg). The β-carotene content was 17.70 mg/kg. The fatty acid profile of leaves was represented by palmitic C16:0 (44.6 g/100 g of oil), linoleic C18:2 9c12c (17.9 g/100 g of oil), and α-linolenic C18:3 (9c12c15c 10.6 g/100 g of oil) acids. Nine out of 18 amino acids detected in leaves were essential amino acids (68.80 g/kg of dry matter leaves). Glutamic acid was found to be the major component of non-essential amino acids (25 g/kg of dry matter), followed by aspartic acid (16.2 g/kg of dry matter) and leucine (14.2 g/kg of dry matter). The element composition of leaves demonstrated the presence of: macroelements (K, P, S, Ca, Mg, Na), microelements (Zn, Fe, Cu, Mn, Cr, Se), and metals (Al, As, Cd, Ni, Hg, Pb). Potassium was the most abundant element in Schisandra chinensis leaves (10209 mg/kg of dry matter of leaves), followed by Ca, P, and Mg. The spectrophotometric assays enabled detecting phenolic compounds from three categories: polyphenols (44.32 mg galic acid equivalents/g of dry matter of leaves), total flavonoids (29.16 mg quercetin equivalents/g of dry matter of leaves) and phenolic acids (6.12 mg caffeic acid equivalents/g of dry matter of leaves) in Schisandra chinensis leaves. The antioxidant activity of S. chinensis leaves, as determined by DPPH•, was at the level of 9.19 mg TEAC/g of dry matter of leaves, and 214 mg TEAC/g of dry matter of leaves (as determined by molybdenum reducing antioxidant power). The composition of Schisandra chinensis leaves suggest it to become an inexpensive novel plant source of functional foods, supplements, and as new ingredient in human diet.

Influence of Lipid Membranes on α-Synuclein Aggregation.

α-Synuclein is a neuronal protein involved in synaptic vesicle trafficking. During the course of Parkinson's disease, it aggregates, forming amyloid fibrils that accumulate in the midbrain. This pathological fibrillization process is strongly modulated by physiological interactions of α-synuclein with lipid membranes. However, the detailed mechanism of this effect remains unclear. In this work, we used environment-sensitive fluorescent dyes to study the influence of model lipid membranes on the kinetics of α-synuclein fibrillization. We observed that formation of the fibrils from α-synuclein monomers is strongly delayed even by small amounts of lipids. Furthermore, we found that membrane-bound α-synuclein monomers are not involved in fibril elongation. Hence, presence of lipids slows down fibril growth proportionally to the fraction of membrane-bound protein.

Elemental identification of blue paintings traces present in historic cemeteries in the São Martinho region, southern Brazil

Cemeteries are of great significance in many communities, often being considered of invaluable historical, artistic, architectural and cultural significance and thus they need to be preserved. In this regard, understanding the historical aspects and the construction techniques used is essential for their protection. The purpose of this paper is to describe historical aspects of the funerary heritage present in the region of São Martinho in southern Brazil, along with an analysis of the blue paint found in cemeteries of German colonies in the region studied. FTIR analysis suggests that the binder is composed mostly of a protein resin and a small amount of lipid. The morphology of the pigment was investigated by SEM and EDS and the spectra revealed that the major elements present in the blue pigment are Na, Al, Si and S, with an overlap in the elemental mapping, indicative of ultramarine pigments. The GC-MS results are consistent with the type of binder identified by FTIR and indicate a mixture of oils, probably from vegetal sources, and proteins.

Reactive Oxygen Species-Mediated Cellular Stress Response and Lipid Accumulation in Oleaginous Microorganisms: The State of the Art and Future Perspectives.

Microbial oils, which are mainly extracted from yeasts, molds, and algae, have been of considerable interest as food additives and biofuel resources due to their high lipid content. While these oleaginous microorganisms generally produce only small amounts of lipids under optimal growth conditions, their lipid accumulation machinery can be induced by environmental stresses, such as nutrient limitation and an inhospitable physical environmental. As common second messengers of many stress factors, reactive oxygen species (ROS) may act as a regulator of cellular responses to extracellular environmental signaling. Furthermore, increasing evidence indicates that ROS may act as a mediator of lipid accumulation, which is associated with dramatic changes in the transcriptome, proteome, and metabolome. However, the specific mechanisms of ROS involvement in the crosstalk between extracellular stress signaling and intracellular lipid synthesis require further investigation. Here, we summarize current knowledge on stress-induced lipid biosynthesis and the putative role of ROS in the control of lipid accumulation in oleaginous microorganisms. Understanding such links may provide guidance for the development of stress-based strategies to enhance microbial lipid production.

Glomerular Lesions in Proteinuric Miniature Schnauzer Dogs.

Miniature Schnauzer dogs are predisposed to idiopathic hypertriglyerceridemia, which increases risk for diseases such as pancreatitis and gallbladder mucocele. Recently, elevated triglyceride concentrations have been associated with proteinuria in this breed, although it is difficult to determine which abnormality is primary. Retrospective review of renal tissue from 27 proteinuric Miniature Schnauzers revealed that 20 dogs had ultrastructural evidence of osmophilic globules consistent with lipid in glomerular tufts. Seven of these dogs had lipid thromboemboli in glomerular capillary loops that distorted their shape and compressed circulating erythrocytes. Triglyceride concentrations were reported in 6 of these 7 dogs, and all were hypertriglyceridemic. In addition, glomerular lipidosis (defined as accumulation of foam cells within peripheral capillary loops) was identified in a single dog. The remaining 12 dogs had smaller amounts of lipid that could only be identified ultrastructurally. Neither signalment data nor clinicopathologic parameters (serum albumin, serum creatinine, urine protein-to-creatinine ratio, and blood pressure) differed among the various types of lipid lesions. During the time course of this study, all dogs diagnosed with glomerular lipid thromboemboli were Miniature Schnauzers, underscoring the importance of recognizing these clear spaces within capillary loops as lipid.

Body cavity cells of Parachela during their active life

The body cavity cells (storage cells, storage bodies) of four species of Parachela (hermaphroditic Isohypsibius granulifer granulifer, parthenogenetic Hypsibius dujardini, gonochoristic Xerobiotus pseudohufelandi, gonochoristic Macrobiotus polonicus) were analysed during their active life using light, confocal (laser scanning), and scanning and transmission electron microscopy. The ultrastructure of the storage cells confirmed previous studies suggesting a high level of metabolic activity. Additionally, we revealed the participation of the storage cells of H. dujardini, I. g. granulifer, and M. polonicus in the synthesis of vitellogenins. This did not seem to apply for X. pseudohufelandi. All of the species that were examined in this study accumulated polysaccharides, proteins, and lipids in their body cavity cells, but the amount of these components differed in each species. Isohypsibius g. granulifer accumulated a huge amount of polysaccharides and smaller amounts of lipids and proteins, H. dujardini and M. polonicus primarily accumulated lipids and small amounts of polysaccharides and proteins, whereas X. pseudohufelandi primarily accumulated polysaccharides and lipids, and a small amount of proteins.

ГИСТОХИМИЧЕСКАЯ ХАРАКТЕРИСТИКА ГИПОФИЗА КРУПНОГО РОГАТОГО СКОТА

Histochemical studies allowed to investigate the main aspects of the chemical statics and dynamics of the pituitary gland: location and nature of the reaction to the contents of nucleic acids, proteins, and lipids in cattle of different ages.It is installed the increased intensity of histochemical reactions to identify DNA and RNA. This indicates about the nucleic nature of the colloid, which is produced by the body and is a carrier of hormonal substances. The greatest concentration of nucleic acids was observed in the adenohypophysis of animals of 6 months of age. Here they are accumulated more in the adenocytes nuclei. The cells of a connective–tissue capsule of the pituitary gland have increased intensity of histochemical reactions to identify nucleic acids. Common proteins found in all histoststructure of the pituitary gland, but sometimes the preferential localization of the total protein in the pituitary gland of cattle in the age aspect is the anterior pituitary. The lipid in microstructures of the pituitary gland contained in all its parts. The intermediate fraction and the capsule of the pituitary gland are rich by them. Fat cells in the structures of the pituitary gland have not been identified because they usually are contained in the form of biocomplexity connections.The nature of the histochemical features of the pituitary gland of cattle depends on the age of the animals, and we studied the histochemical reactions of the colloid allow to characterize it as a mucopolysaccharide with impurities of proteins and a small amount of lipids.

Morphology and Cyclic Activity of the Digestive Gland ofZidona dufresnei(Caenogastropoda: Volutidae)

Zidona dufresnei is a carnivorous snail that plays an important role in the trophic web as a top predator. It is a threatened species due to high levels of fisheries exploitation. In this study, we describe the morphology of the digestive gland of Z. dufresnei from Mar del Plata, Argentina, and discuss the function and the cycle of activity of the different cell types. Histological analysis reveals two types of tubules: type 1 tubules composed of digestive and basophilic cells and type 2 tubules lined by basophilic cells only. Pyramidal basophilic cells contain lipofuscin and a large amount of rough endoplasmic reticulum, which suggests that these cells are responsible for the secretion of digestive enzymes that initiate the extracellular digestion of the food. Columnar digestive cells exhibit large membrane-bound vesicles that contain proteoglycans, neutral glycosaminoglycans and small amounts of lipid and lipofuscin. The presence in digestive cells of many endocytic vesicles and residual lysosomal bodies, as evidenced by the presence of lipofuscin pigments in the apical region, indicate that digestion is completed intracellularly within these cells. The digestive cells are subject to cyclical changes involving four phases: initial, digestion, fragmentation, and disintegration stages.

Poster #T175 NPAS3: NEW GENETIC AND BIOLOGICAL FINDINGS WITH IMPLICATIONS FOR PROTEIN AGGREGATION AND SCHIZOPHRENIA

This chapter discusses the advances in the chromatography of lipids. The method of preparation of a lipid extract constitutes one of the most critical parts of lipid analysis by chromatographic methods. Extraction with organic solvents provides a simple method of isolating all major phospholipids regardless of their fatty-acid composition. The isolation of the minor acidic phosphoinositol phosphatides (PtdInsPs) requires acidification, which causes the destruction of plasmalogens unless they are removed first. Good laboratory practice recommends that the lipid extractions be performed in the presence of butylated hydroxy toluene (BHT) or other antioxidants, especially when working with small amounts of lipid. Because PtdInsPs and their products of hydrolysis are degraded very rapidly, it is essential either to extract the samples immediately after collection or to freeze the samples in situ after collection and store them at −70oC. In situ fixation of samples by freeze clamping or by microwave irradiation may be helpful in arresting the degradation of phosphate esters.

Feather keratin hydrolysates obtained from microbial keratinases: effect on hair fiber

BackgroundHair is composed mainly of keratin protein and a small amount of lipid. Protein hydrolysates, in particular those with low molecular weight distribution have been known to protect hair against chemical and environmental damage. Many types of protein hydrolysates from plants and animals have been used in hair and personal care such as keratin hydrolysates obtained from nails, horns and wool. Most of these hydrolysates are obtained by chemical hydrolysis and hydrothermal methods, but recently hydrolyzed hair keratin, feather keratin peptides, and feather meal peptides have been obtained by enzymatic hydrolysis using Bacillus spp in submerged fermentation.ResultsKeratin peptides were obtained by enzymatic hydrolysis of keratinases using Bacillus subtilis AMR. The microorganism was grown on a feather medium, pH 8.0 (1% feathers) and supplemented with 0.01% of yeast extract, for 5 days, at 28°C with agitation. The supernatant containing the hydrolysates was colleted by centrifugation and ultra filtered in an AMICON system using nano–membranes (Millipore – YC05). The Proteins and peptides were analyzed using HPTLC and MALDI-TOF-MS. Commercial preparations of keratin hydrolysates were used as a comparative standard. After five days the feather had been degraded (90-95%) by the peptidases and keratinases of the microorganism. MALDI-TOF mass spectrometry showed multiple peaks that correspond to peptides in the range of 800 to 1079 Daltons and the commercial hydrolysate was in the range of 900 to 1400 Da. HPTLC showed lower molecular mass peptides and amino acids in the enzymatic hydrolysate when compared with the commercial hydrolysate . A mild shampoo and a rinse off conditioner were formulated with the enzymatic hydrolysate and applied to hair fibers to evaluate the hydration, with and without heat, using a Corneometer® CM 825. The hydration was more efficient with heat, suggesting a more complete incorporation of hydrolysates into the fibers. Scanning Electron Microscopy showed deposits of organic matter in the junction of the cuticles that probably collaborates to the sealing of the cuticles, increasing the brightness and softness.ConclusionsThese results show that the enzymatic method to produce keratin peptides for hair care products is an attractive and eco- friendly method with a great potential in the cosmetic industry.

Temperature Behavior of Nanometer-Size Lipid Domains in DPPC:DLPC Model Membranes Studied by Small Angle Neutron Scattering

Cellular membranes are no longer viewed as a heterogeneous mix of lipids and proteins, but rather as having distinct lipid domains which are key for many biological processes. Much work devoted to understanding the mechanisms that drives lateral organization in cell membranes has been done on model membrane systems. The study of lipid-lipid phase separation contributes to our understanding of the structure-function relation in the cell membrane. Phase behavior of lipid mixtures has been studied extensively in model lipid membranes using microscopy and spectroscopy techniques. By microscopy, the domains are found to be microns in size. A hypothesis to explain small domains in real cell membranes is that the cytoskeleton generates boundaries, generating small membrane regions with access to only a small amount of lipids and other components. Therefore, to be able to correlate studies of model membranes to the actual plasma membrane, there is a need to characterize lipids domains in a system where they cannot grow more than few nanometers in size. To achieve such a goal, we use Small Unilamellar Vesicles made of a 1:1 ratio of deuterated DPPC and DLPC for which phase separation in large vesicles has been observed. Small Angle Neutron Scattering was used to characterize the size and composition of the domains, which appeared as the temperature was lowered below the Tm of the system (which lies between the two Tm values of each lipid depending on the composition). The scattering was fitted using an ab initio method developed by Svergun and colleagues to analyze scattering data from biological macromolecules. The results show that domains in these systems do not coalesce to form a single stable domain but rather break-up into smaller domains as the temperature lowers.

Removal of an endotoxin fragment (lipid A) with an endotoxin-retentive filter

Endotoxin-retentive filters are used to purify the dialysate used for hemodialysis, but endotoxin fragments whose molecular weight is below the molecular weight cut-off point of the filter may pass through the filter. The objective of the present study was to determine whether lipid A, an endotoxin fragment, is sufficiently removed by an endotoxin-retentive filter. A filtration test for lipid A was carried out using an endotoxin-retentive filter. The filtrate was tested for the presence of lipid A by a biochemical analysis: the Limulus lysate test and a bioassay: the lymphocyte stimulation test. The endotoxin-retentive filter removed lipid A to below the limit of detection by the Limulus lysate test. However, the filtrate stimulated lymphocytes, suggesting that a small amount of lipid A whose concentration was below the limit of detection by the Limulus lysate test had passed through the filter. In conclusion, the endotoxin-retentive filter was capable of removing lipid A to a concentration below the limit of detection by the Limulus lysate test but the filtrate still stimulated lymphocytes.

Understanding the Behavior of Nanometer-Size Lipid Domains in Model Membranes: A Small Angle Neutron Scattering Study

Lipid-lipid phase separation is important in understanding the behavior of the biological membrane. Such phenomenon has been studied extensively in model lipid membranes using microscopy techniques where domains are found to be microns in size. In actual biological membranes, however, domains are smaller, and microscopy techniques are unable to detect them. A hypothesis to explain these small domains is that the cytoskeleton generates boundaries to compartmentalize the membrane into small sub-membrane regions with access to only small amounts of lipids in the lifespan of lipid domains. Therefore, to be able to correlate studies of model membranes to the actual plasma membrane, there is a need to characterize lipid domains in a system where they cannot grow more than few nanometers in size. To achieve such a goal, we use small Unilemellar Vesicles (ULVs) made of 1:1 and 3:7 ratios of DPPC (deuterated-DPPC) and DLPC respectively for which phase separation in large vesicles has been observed. Using small vesicles with varying sizes (diameters from 30nm to 400nm) not only provides a means to control curvature, but also limits the amount of available lipids for domain growth. Small Angle Neutron Scattering was used to characterize the size, density and average composition of the domains, which appeared as the temperature was lowered below Tm, the melting temperature of the system. The scattering curves were fitted using a pair-correlation method in order to extract the “local structure” of the vesicles. The results interestingly suggest that the nanometer domains in these systems do not coalesce to form a single stable domain as observed in giant vesicles. Overall, thiswork provides insight into the behavior of nano-meter size lipid-lipid phase separation as a function of composition, temperature, vesicle-size and curvature.

Intracellular lipid droplet targeting by apolipoprotein A-V requires the carboxyl-terminal segment

The expression of apolipoprotein A-V (apoA-V) in hepatoma cells results in homing of this protein to intracellular lipid droplets. When hepatoma cells transfected with a full-length apoA-V-green fluorescent protein fusion protein were cultured in medium that was not supplemented with oleic acid (OA), intracellular lipid droplet size and number were reduced compared with those of cells supplemented with OA. Confocal microscopy studies revealed that apoA-V associates with lipid droplets under both conditions. To define the structural requirements for apoA-V lipid droplet association, hepatoma cells were transfected with a series of C-terminal truncated apoA-V variants. Confocal microscopy analysis revealed that, in a manner similar to mature full-length apoA-V (343 amino acids), truncation variants apoA-V(1-292), apoA-V(1-237), and apoA-V(1-191) associated with lipid droplets, while apoA-V(1-146) did not. Western blot analysis of the relative abundance of apoA-V in cell lysates versus conditioned medium indicated that apoA-V variants associated with lipid droplets were poorly secreted while apoA-V(1-146) was efficiently secreted. Ultracentrifugation of conditioned medium revealed that, unlike full-length apoA-V, which associates with lipoproteins, apoA-V(1-146) was present solely in the lipoprotein-deficient fraction. Deletion of the N-terminal signal peptide from apoA-V resulted in an inability of the protein to be secreted into the medium, although it associated with lipid droplets. Taken together, these data suggest that the C terminus of apoA-V is essential for lipid droplet association in transfected hepatoma cells and lipoprotein association in conditioned medium while the signal peptide is required for extracellular trafficking of this protein.

Microanalytical systems for separations of stratum corneum ceramides

The small amount of lipids from human skin obtained with noninvasive sampling method led us to investigate microanalytical separation techniques. The lipid class analysis was performed with a micro polyvinyl alcohol-silica (PVA-Sil) column. The gradient elution was from heptane to acetone/butanol 90:10 v/v in 4%/min at 78 microL/min. In addition an evaporative light scattering detector (ELSD) was modified for micro-LC. All solvents contained 0.1% of triethylamine and formic acid in stoichiometric amount, which increased the ELSD response. In these conditions, the cholesterol eluted before free fatty acid, and squalene and triglycerides close to the dead volume. The various ceramide classes eluted following the order of the increased number of hydroxyl groups. The LOD for ceramides was 2.2 ng. The advantages of this method are the use of a normal stationary phase more reliable due to its chemical stability, its surface homogeneity and its development in microchromatography without chlorinated solvents which offers small LOD and the whole profile of lipids present in stratum corneum (SC). A method using a narrow-bore PVA-Sil column was used to collect ceramide fraction. Then the molecular species were analysed with a porous graphitic carbon column in capillary LC using a gradient from CH3OH/CHCl3 70:30 v/v to CHCl3 at 2%/min with a flow rate at 5 microL/min. The LOD obtained for ceramide was 1 ng. Both methods were assessed with SC samples obtained by rinsing a 5.7 cm2 area of the forearm with 25 mL of ethanol.

Microsomal Triglyceride Transfer Protein Promotes the Secretion of Xenopus laevis Vitellogenin A1

Vitellogenins (Vtg) are ancient lipid transport and storage proteins and members of the large lipid transfer protein (LLTP) gene family, which includes insect apolipophorin II/I, apolipoprotein B (apoB), and the microsomal triglyceride transfer protein (MTP). Lipidation of Vtg occurs at its site of synthesis in vertebrate liver, insect fat body, and nematode intestine; however, the mechanism of Vtg lipid acquisition is unknown. To explore whether Vtg biogenesis requires the apoB cofactor and LLTP family member, MTP, Vtg was expressed in COS cells with and without coexpression of the 97-kDa subunit of human MTP. Expression of Vtg alone gave rise to a approximately 220-kDa apoprotein, which was predominantly confined to an intracellular location. Coexpression of Vtg with human MTP enhanced Vtg secretion by 5-fold, without dramatically affecting its intracellular stability. A comparison of wild type and a triglyceride transfer-defective form of MTP revealed that both were capable of promoting Vtg secretion, whereas only wild type MTP could promote the secretion of apoB41 (amino-terminal 41% of apoB). These studies demonstrate that the biogenesis of Vtg is MTP-dependent and that MTP is the likely ancestral member of the LLTP gene family.

Relation between extracellular polymers’ composition and its ability to complex Cd, Cu and Pb

Activated sludges originated from wastewater treatment plants (WWTPs) play an important role in heavy metal removal from effluents. Extracellular polymers (ECP) form a major part of the activated sludge and are heavily involved in biosorption of heavy metals. The complexation of three heavy metals (Cd, Cu and Pb) with ECP extracted from six activated sludges, originated from different WWTPs, was investigated at pH 7. ECP in the study were shown to be mainly composed of proteins, humic acids, uronic acids and polysaccharides along with smaller amounts of lipids and nucleic acids. IR spectra confirmed the presence of the functional groups usually found in the ECP and the content in each fraction was determined using colorimetric methods. The determination of surface charge was carried out on each ECP sample and allowed two p K a values characteristic of two distinctive functional groups to be determined. At the pH used in the study, the value of these constants indicates that only one functional group is under protonated form. A polarographic method was used to determine the complexation parameters (number of binding sites and complexation constant) of ECP solutions towards metals. The following orders were established for the number of binding sites: Cu > Pb ≫ Cd and for the stability of the ECP–metal complex: Cd > Pb ∼ Cu. A matrix of correlation between the composition of the polymers and the complexation parameters showed that the number of binding sites and the complexation constant were strongly linked to proteins, polysaccharides and humic substances content.

Amount of Squalene and Fatty Acid Composition of Triacylglycerols and Phospholipids in Flesh and Liver Lipids of Some Deep-sea Teleost Fish, Morid Cods and Whiptails

Examination was made of the amounts of squalene and fatty acid compositions of triacylglycerols (TG) and phospholipids (PL) in the flesh and liver lipids of five species of deep-sea teleost fish: the Pacific flatnose Antimora microlepis and the black mora Halargyreus johnsonii of morid cods and the roughscale rattail Coryphaenoides acrolepis, the pop-eye grenadier C. cinereus and the pectoral rattail C. pectoralis of whiptails. Liver specimens of these deep-sea teleost fish contained copious amounts of lipids (19.5-65.1%) which were composed almost entirely of TG (72.6-95.9%). Flesh samples contained small amounts of lipids (0.3-0.5%) with lower TG (0.9-1.4%) and higher PL (53.8-76.0%) content. In the livers and flesh, unsaponifiable matter from the neutral lipids comprised squalene (42.4-57.7% and 3.7-10.3%) and sterols (22.8-51.0% and 84.0-95.3%), respectively, and the squalene content of liver lipids corresponded to 0.57-1.76%. Component fatty acids in TG from liver lipids were characteristically rich in monoenes (59.5-73.0%) with 22:1n-11 (15.7-24.1%), 18:1n-9 (11.2-16.6%) and 20:1n-11 (8.7-10.9%) acids. Nevertheless, component fatty acids in PL from flesh lipids were rich in polyenes (37.6-44.2%) with 22:6n-3 (23.1-28.4%) and 20:5n-3 (8.7-8.8%) acids.

Factors that influence assimilation rates and fractionation of nitrogen and carbon stable isotopes in avian blood and feathers.

By switching great skuas Catharacta skua from one isotopically distinct diet to another, we measured diet-tissue discrimination factors and tested the assumption that dietary nitrogen and carbon isotope signatures are incorporated into blood and feathers at similar rates. We also examined the effects of metabolic rate and looked for evidence of isotopic routing. We found that blood delta(15)N and delta(13)C signatures altered after the diet switch at similar rates (14.4 d and 15.7 d, respectively). Qualitative analyses imply that the same was true with feathers. Mass balance calculations suggest that only a small amount of lipid is likely to be involved in the synthesis of blood and feathers. Differences in diet-tissue discrimination factors before and after the diet switch may mean that toward the end of the experiment, some of the nutrients for blood synthesis had been coming from stores. Repeated measures mixed models provided evidence that increases in metabolic rate might accelerate fractional turnover rates in blood. There is a need for more laboratory-based experimental isotope studies in order to address further questions that this study has raised.