Comparative Lipid Analysis Research Articles

Modulation of lipid metabolism and spiramycin biosynthesis in Streptomyces ambofaciens unstable mutants.

Streptomyces ambofaciens is prone to genetic instability involving genomic rearrangements at the extremities of the chromosomal DNA. An amplified DNA sequence (ADS205), including an open reading frame (orfPS), is responsible for the reversible loss of spiramycin production in the mutant strain NSA205 (ADS205(+) Spi-). The product of orfPS is homologous to polyketide synthase systems (PKSs) involved in the biosynthesis of erythromycin and rapamycin and is overexpressed in strain NSA205 compared with the parental strain RP181110. As PKSs and fatty acid synthase systems have the same precursors, we tested the possibility that overexpression of orfPS also affects lipid metabolism in strain NSA205. This report focuses on comparative analysis of lipids in strain RP181110, the mutant strain NSA205, and a derivative, NSA228 (ADS205(-) Spi+). NSA205 showed a dramatically depressed lipid content consisting predominantly of phospholipids and triacylglycerols. This lipid content was globally restored in strain NSA228, which had lost ADS205. Furthermore, strains RP181110 and NSA205 presented similar phospholipid and triacylglycerol compositions. No abnormal fatty acids were detected in NSA205.

Respiratory components in acidophilic bacteria that respire on iron

Abstract Microorganisms capable of aerobic respiration on ferrous ions are spread throughout eubacterial and archaebacterial phyla. Phylogenetically distinct organisms were shown to express spectrally distinct redox‐active biomolecules during autotrophic growth on soluble iron. A new iron‐oxidizing eubacterium, designated as strain Funis, was investigated. Strain Funis was judged to be different from other known iron‐oxidizing bacteria on the bases of comparative lipid analyses, 16S rRNA sequence analyses, and cytochrome composition studies. When grown autotrophically on ferrous ions, Funis produced conspicuous levels of a novel acid‐stable, acid‐soluble yellow cytochrome with a distinctive absorbance peak at 579 nm in the reduced state. Stopped‐flow spectrophotometric kinetic studies were conducted on respiratory chain components isolated from cell‐free extracts of Thiobacillus ferrooxidans. Experimental results were consistent with a model where the primary oxidant of ferrous ions is a highly aggregated...

Comparative analysis of extractable lipids in hot spring microbial mats and their component photosynthetic bacteria

The extractable hydrocarbons, wax esters, alcohols and fatty acids of hot spring microbial mats and bacteria were compared to investigate whether the distribution of important biomarker lpids parallels the distribution of photosynthetic microorganisms of different types. Two cyanobacterial mats, two anoxygenic photosynapetic bacterial mats, and their component photosynthetic bacteria (Chloroflexus aurantics, Chromatium tepiduum and Chlorobiumsp.) wwere investigated. In general, mat lipids reflect the inputs of the principal mat-building phototropic microorganisms therein. Cyanobacterial mats contain mainly hydrocarbons, principally n-heptadecane and mid-chain branched alkanes; the latter are absent in photosynthetic bacterial mats and bacteria. Hydrocarbons are not abundant in photosynthetic bacteria and mats, with the exception that C. aurantiacus is distinguished by C 29-C 32 mono-, di- and triunsaturated alkenes. Wax esters are principal components of C. aurantiacus and Chlorobiumsp, and mats containing these organisms. Predominating free alcohols reflect the distribution of chlorophyll a or bacteriochlorophylls in the phototrophi microorganisms of the mats. Traces of sterols in both cyanobacterial and the anoxic photosynthetic bacterial umts are probably of allochthonous origin. Free fatty acids are minor components and are similar in all mats.

Lipid-rich cell thyroid adenoma: histopathology with comparative lipid analysis

A second case of the unique lipid-rich cell thyroid adenoma is described complemented by detailed lipid analysis. New observations were made. The cytoplasm of the tumour cells contained scattered, aggregated sudanophil crystals; under polarized light the frozen, unstained sections exhibited numerous birefringent lipid crystals; electron microscopy provided further evidence that the clear cell appearance was due to intracellular lipid droplets with scanty glycogen particles. Comparative lipid analysis by thin layer chromatography and high-pressure liquid chromatography (HPLC) revealed quantitative and qualitative differences in lipid composition of tumour cells when compared with goitre cells from normal thyroid gland and subcutane fat. Qualitative differences in triglyceride composition (by HPLC) between tumour cells and subcutaneous fat indicated that the fat accumulation in the follicle cells was not a result of simple storage, but an expression of altered intracellular lipid metabolism.

Evaluation of jojoba oil as a low-energy fat. 2. Intestinal transit time, stomach emptying and digestibility in short-term feeding studies in rats

The influence of jojoba oil (JO) incorporation in the diet on stomach emptying and intestinal transit time, and the digestion and absorption of JO were investigated in short-term feeding studies in rats. The animals were fed purified diets containing 18% (w/w) fat, of which half consisted of a mixture of lard and sunflower seed oil (SF) supplemented with an equivalent amount of JO. The control animals were fed a mixture of lard and SF (18%). No treatment-related differences were observed in the rate of stomach emptying or the intestinal transit time. Comparative lipid analysis of lymph, intestinal content, intestinal mucosa and faeces indicated that most of the ingested JO was degraded and absorbed. Part of the JO was present as wax ester in the lymph. Hydrolysis of JO was much slower than that of triacylglycerols and continued in the alimentary tract beyond the small intestine due to bacterial processes. JO did not influence the absorption of the conventional fat.

Comparative analysis of total proteins, amino acids, carbohydrates, fibers, lipids, macro and micro minerals contents in different types of Egyptian bread

Seven types of Egyptian bread were collected from different rural and urban areas. The chemical composition including total proteins, amino acids, carbohydrates, fibers, lipids, macro and micro minerals contents were determined. Total proteins content was higher in shamssy bread than other types of bread. Crude fat has the highest value in bread made from mixture of cereals, especially when trigonella is found, while fiber content was highest when mixture of cereals containing sorghum is used. Ash content of bread made from maize + wheat showed a higher value than other types and the differences were highly significant. Ca, Mg, Cu, and Fe were higher in bread made from sorghum + trigonella blend than other types of bread. Variations in the amino acids content of the different types of bread were found; these differences due to the origin of different cereals, the method of bread processing and the differences in the extraction rates of the flour.

Use of Percoll™ in the isolation and purification of rabbit small intestinal brush border membranes

(1) Intestinal absorption is altered under a variety of circumstances in health and disease and to determine a possible relationship between intestinal absorptive function and intestinal brush border membrane composition, we undertook the isolation and purification of rabbit jejunal and ileal brush borders, to allow further studies of their lipid composition under varied experimental conditions. (2) A modification of an established method (Schmitz, J., Preiser, H., Maestracci, D., Ghosh, B.K., Cerda, J.J. and Crane, R.K. (1973) Biochim. Biophys. Acta 323, 98–112) utilized CaCl 2 aggregation and sequential centrifugation followed by purification of the brush border pellet (P 2) at 27 000 × g on a Percoll™ (Pharmacia) self-forming gradient. The Percoll™ was removed by ultracentrifugation for 30 min at 100 000 × g, utilizing a batch rotor in the Beckman airfuge™. (3) Pure brush border membrane vesicles were obtained and characterized by specific marker analysis and electron microscopy. Comparative marker analyses performed on P 2 and final Percoll™ preparations from animals showed that the purification achieved was 8–11-fold greater when compared to the original homogenates. Verification of purity was also demonstrated by the absence of DNA and very low levels of β-gluconridase and (Na + + K +)-ATPase in the Percoll™ preparations. (4) Comparative lipid analyses of P 2 and final Percoll™ preparations showed that levels of total phospholipid and free fatty acids were several-fold higher in the Percoll™ preparations on a per mg protein basis. (5) A comparison of the activity of enzyme markers and the levels of total free fatty acids in P 2 pellets obtained after CaCl 2 and MgCl 2 aggregation showed that CaCl 2 aggregation gave the more consistently reproducible results. (6) Although standard procedures of membrane preparations not involving density gradient separation provide membranes of reasonable purity for the estimation of lipid components, we consider the final purification step of density gradient separation using Percoll™ is essential for determining small quantitative changes which might occur in the membrane lipid composition under experimental conditions where intestinal absorptive function is altered.

Comparative lipid analysis of purified plasma membranes and shed extracellular membrane vesicles from normal murine thymocytes and leukemic GRSL cells

The lipid fluidity in purified plasma membranes (PM) of murine leukemic GRSL cells, as measured by fluorescence polarization, is much higher than in PM of normal thymocytes. This was found to be due to relatively low contents of cholesterol and sphingomyelin and a high amount of unsaturated fatty acyl chains, especially linoleic acid, in the phospholipids. PM from GRSL cells contain markedly more phosphatidylethanolamine than those from thymocytes. For both GRSL cells and thymocytes the detailed lipid composition of isolated PM was compared with that of the corresponding shed extracellular membranes (ECM), which were isolated from the ascites fluid and from thymus cell suspensions, respectively. The somewhat decreased lipid fluidity of thymocyte ECM as compared to their PM, can be ascribed to the increased cholesterol/phospholipid molar ratio (0.88 vs. 0.74). No other major differences were found between the lipid composition of these membranes. In contrast, significant differences were found between PM and ECM from GRSL cells. In this system a much lower lipid fluidity of the shed ECM was found, due to the much increased cholesterol/phospholipid molar ratio (3.5-fold) and sphingomyelin (9-fold) content, as compared to the PM. Further, the ECM contain relatively more lysophosphatidylethanolamine and less phosphatidylcholine and -inositol. ECM contain a higher amount of polyunsaturated fatty acids, especially in the phosphatidylethanolamine and lysophosphatidylethanolamine classes. On the other hand, the fatty acids of phosphatidylcholine and lysophosphatidylcholine are more saturated than in PM. In particular, ECM of GRSL cells contain less oleic and linoleic acid residues and more arachidonic acid and 22:polyunsaturated fatty acid residues than PM. The possible relevance of these differences with respect to the mechanism of shedding of vesicles from the cell surface, is discussed.

Fatty acid composition of lipids of Escherichia coli W 1655 F+ and its stable protoplast type L-form.

The comparative fatty acid analysis of extractable and non-extractable lipids of Escherichia coli W 1655 F+ and its stable protoplast type L-form shows quantitative as well as qualitative differences. From 10 different fatty acids obtained 16:0, 17:0 and 18:0 are present at about the same quantities in the lipid fractions of the bacterial and L-form. The absence of larger amounts of 12:0, 14:0, and 14:beta OH fatty acids in non-extractable L-form lipids reflects the loss of the cell wall in L-form cells. 16:1 fatty acid was found in L-form lipids only. This qualitative difference and the 2-3 times higher content of 18:1 in L-form lipids and the 7 times lower content of cyc 19:0 in extractable lipids of the L-form may be interpreted as alterations characteristic for the changed composition of the cytoplasmic membrane in L-form cells.

Fatty acid composition of lipids in the maternal diet and establishment of a Lactobacillus sp. strain in the digestive tract of suckling gnotobiotic mice and rats

Adult gnotobiotic mice and rats, monoassociated with a homofermentative strain of Lactobacillus sp. of intestinal origin, were fed either a commercial rodent chow A or a semisynthetic diet B. Similar numbers of lactobacilli were established in their gastrointestinal tract whatever diet they ate. The lactobacilli were established in the digestive tract of the newborn of A mothers at 2 days but were hardly established in mouse or rat pups of A mothers than in their mouse homologues. Comparative analysis of milk lipids in the A and B series showed a linoleic acid (18:2 n-6) content which was three times higher in the B than in the A series. Two diets S and H differing only by their lipid fractions, which, respectively, presented the same fatty acid compositions as lipids from diets A and B were then given to two others lots of Lactobacillus monoassociated mice. The establishment kinetics of the strain were the same in the mouse pups of these two lots precedently observed in the B series. The difference observed in the establishment kinetics of the Lactobacillus strain in the digestive tract of suckling gnotobiotic mice was thus attributed to other dietary factors than the fatty acid composition of the maternal diet.

VI. Comparative lipid analysis of Aedes aegypti and monkey kidney cells (MK-2) cultivated in vitro.

Lipid composition of several types of mammalian cells has been reported, such as that of the mouse “L” cell (Anderson et al., 1969; Bailey and Menter, 1967) and the monkey kidney cell (MK-2) (Makino et al., 1970), but the arthropods (Barroso et al., 1969; Agarwal and Rao, 1969; Fast, 1966) or the established insect cell lines have not been fully analyzed. Arthropods have been reported as having an active lipid metabolism and appear to depend on fatty acids rather than carbohydrates as a main energy source (O’Brien and Wolfe, 1964). However, arthropods do require a source of dietary sterols since they are unable to synthesize the sterol ring from acetate or mevalonate, but are capable of converting sterol to cholesterol (O’Brien and Wolfe, 1964).KeywordsTotal LipidNeutral LipidSterol EsterSpinner FlaskMonkey Kidney CellThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Comparative analysis of mammary tissue and milk lipids of the sow.

Comparative analysis of mammary tissue and milk lipids of the sow.

Comparative Lipid Analyses of Cortex and Medulla of Beef Adrenals

SummaryWhile the data above are not extensive, we believe them to be of importance in demonstrating lack of agreement between chemical findings and accepted histological technique. (1) Comparative analysis of extracts of both cortex and medulla indicates that the total lipid content of the medulla and cortex of beef adrenals is essentially the same. (2) Study of the individual lipids shows more phosphatide and fatty acids in the cortex and more total, free and combined cholesterol in the medulla.