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Fatty Acid Analysis (fatty + acid_analysis)
Selected AbstractsFatty acid analyses reveal high degrees of omnivory and dietary plasticity in pond-dwelling tadpolesFRESHWATER BIOLOGY, Issue 7 2010MATT R. WHILES Summary 1.,Understanding the trophic relationships of consumers is central to ecology, but constructing meaningful food webs is often difficult because of a lack of detailed information on consumption versus assimilation and high degrees of omnivory. 2.,We used fatty acid analyses to examine the trophic relationships of three common larval anurans (Pseudacris crucifer, Lithobates catesbeianus and Lithobates clamitans) that are often classified as grazers or detritivores. Tadpoles and potential food sources were sampled in four ponds in southern Illinois and analysed for fatty acid composition. Single linkage cluster analysis was then used to compare fatty acid profiles among tadpole gut contents, tadpole muscle tissues and available food resources. 3.,Diets varied among species and within species among ponds, but organic sediments consistently contributed most to the fatty acid composition of the gut contents of all species. Fatty acid profiles also indicated that larval insects and phytoplankton were consumed by both L. catesbeianus and L. clamitans in one pond, while L. clamitans and P. crucifer consumed mainly periphyton along with sediments in another pond, and these diet differences appeared linked to physical differences among ponds, with periphyton and/or phytoplankton contributing more to tadpole diets in less shaded ponds. 4.,The fatty acid composition of muscle tissues of L. clamitans, the dominant tadpole in these systems, indicated that plant detritus and bacteria, which were the dominant components of organic sediments in the ponds, were common components of the assimilatory diet. 5.,Results demonstrate the utility of fatty acid analyses for assessing both consumption and assimilation. The tadpole assemblages we examined derive much of their energy from heterotrophic and allochthonous sources and exhibit high dietary plasticity. This information will allow for more accurate and comprehensive assessments of trophic interactions in freshwater habitats, as well as aid in amphibian conservation, management and captive propagation efforts. [source] Identification of phosphatidylserine decarboxylases 1 and 2 from Pichia pastorisFEMS YEAST RESEARCH, Issue 6 2009Tamara Wriessnegger Abstract Genetic manipulation of lipid biosynthetic enzymes allows modification of cellular membranes. We made use of this strategy and constructed mutants in phospholipid metabolism of Pichia pastoris, which is widely used in biotechnology for expression of heterologous proteins. Here we describe identification of two P. pastoris phosphatidylserine decarboxylases (PSDs) encoded by genes homologous to PSD1 and PSD2 from Saccharomyces cerevisiae. Using P. pastoris psd1, and psd2, mutants we investigated the contribution of the respective gene products to phosphatidylethanolamine synthesis, membrane composition and cell growth. Deletion of PSD1 caused loss of PSD activity in mitochondria, a severe growth defect on minimal media and depletion of cellular and mitochondrial phosphatidylethanolamine levels. This defect could not be compensated by Psd2p, but by supplementation with ethanolamine, which is the substrate for the cytidine diphosphate (CDP),ethanolamine pathway, the third route of phosphatidylethanolamine synthesis in yeast. Fatty acid analysis showed selectivity of both Psd1p and Psd2p in vivo for the synthesis of unsaturated phosphatidylethanolamine species. Phosphatidylethanolamine species containing palmitic acid (16:0), however, were preferentially assembled into mitochondria. In summary, this study provides first insight into membrane manipulation of P. pastoris, which may serve as a useful method to modify cell biological properties of this microorganism for biotechnological purposes. [source] Borrelia burgdorferi membranes are the primary targets of reactive oxygen speciesMOLECULAR MICROBIOLOGY, Issue 3 2008Julie A. Boylan Summary Spirochetes living in an oxygen-rich environment or when challenged by host immune cells are exposed to reactive oxygen species (ROS). These species can harm/destroy cysteinyl residues, iron-sulphur clusters, DNA and polyunsaturated lipids, leading to inhibition of growth or cell death. Because Borrelia burgdorferi contains no intracellular iron, DNA is most likely not a major target for ROS via Fenton reaction. In support of this, growth of B. burgdorferi in the presence of 5 mM H2O2 had no effect on the DNA mutation rate (spontaneous coumermycin A1 resistance), and cells treated with 10 mM t -butyl hydroperoxide or 10 mM H2O2 show no increase in DNA damage. Unlike most bacteria, B. burgdorferi incorporates ROS-susceptible polyunsaturated fatty acids from the environment into their membranes. Analysis of lipoxidase-treated B. burgdorferi cells by Electron Microscopy showed significant irregularities indicative of membrane damage. Fatty acid analysis of cells treated with lipoxidase indicated that host-derived linoleic acid had been dramatically reduced (50-fold) in these cells, with a corresponding increase in the levels of malondialdehyde by-product (fourfold). These data suggest that B. burgdorferi membrane lipids are targets for attack by ROS encountered in the various stages of the infective cycle. [source] Microspore mutagenesis of Brassica species for fatty acid modifications: a preliminary evaluationPLANT BREEDING, Issue 5 2008A. M. R. Ferrie Abstract A microspore mutagenesis protocol was developed for Brassica rapa, Brassica napus and Brassica juncea for the production of double haploid lines with novel fatty acid profiles in the seed oil. Freshly isolated Brassica microspores were first cultured with ethyl methane sulphonate (EMS) for 1.5 h. The EMS was removed and the microspores were then cultured according to the standard Brassica microspore culture protocol. This protocol was used to generate over 80 000 Brassica haploid/double haploid plants. Field evaluation of B. napus and B. juncea double haploids was conducted between 2000 and 2003. Fatty acid analysis of the B. napus double haploid lines showed that saturated fatty acid proportions ranged from 5.0% to 7.7%. For B. juncea, saturate proportions ranged from 5.4% to 9.5%. Of the 7000 B. rapa lines that were analysed, 197 lines had elevated oleic acid (>55%), 69 lines had reduced ,-linolenic acid (<8%) and 157 lines had low saturated fatty acid proportions (<5%), when compared with the parental lines. [source] The Structure of a Novel Neutral Lipid,A from the Lipopolysaccharide of Bradyrhizobium elkanii Containing Three Mannose Units in the BackboneCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2010Iwona Komaniecka Dr. Abstract The chemical structure of the lipid,A of the lipopolysaccharide (LPS) from Bradyrhizobium elkanii USDA 76 (a member of the group of slow-growing rhizobia) has been established. It differed considerably from lipids,A of other Gram-negative bacteria, in that it completely lacks negatively charged groups (phosphate or uronic acid residues); the glucosamine (GlcpN) disaccharide backbone is replaced by one consisting of 2,3-dideoxy-2,3-diamino- D -glucopyranose (GlcpN3N) and it contains two long-chain fatty acids, which is unusual among rhizobia. The GlcpN3N disaccharide was further substituted by three D -mannopyranose (D -Manp) residues, together forming a pentasaccharide. To establish the structural details of this molecule, 1D and 2D,NMR spectroscopy, chemical composition analyses and high-resolution mass spectrometry methods (electrospray ionisation Fourier-transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and tandem mass spectrometry (MS/MS)) were applied. By using 1D and 2D,NMR spectroscopy experiments, it was confirmed that one D -Manp was linked to C-1 of the reducing GlcpN3N and an ,-(1,6)-linked D -Manp disaccharide was located at C-4, of the non-reducing GlcpN3N (,-linkage). Fatty acid analysis identified 12:0(3-OH) and 14:0(3-OH), which were amide-linked to GlcpN3N. Other lipid,A constituents were long (,-1)-hydroxylated fatty acids with 26,33 carbon atoms, as well as their oxo forms (28:0(27-oxo) and 30:0(29-oxo)). The 28:0(27-OH) was the most abundant acyl residue. As confirmed by high-resolution mass spectrometry techniques, these long-chain fatty acids created two acyloxyacyl residues with the 3-hydroxy fatty acids. Thus, lipid,A from B. elkanii comprised six acyl residues. It was also shown that one of the acyloxyacyl residues could be further acylated by 3-hydroxybutyric acid (linked to the (,-1)-hydroxy group). [source] Fatty acid analyses reveal high degrees of omnivory and dietary plasticity in pond-dwelling tadpolesFRESHWATER BIOLOGY, Issue 7 2010MATT R. WHILES Summary 1.,Understanding the trophic relationships of consumers is central to ecology, but constructing meaningful food webs is often difficult because of a lack of detailed information on consumption versus assimilation and high degrees of omnivory. 2.,We used fatty acid analyses to examine the trophic relationships of three common larval anurans (Pseudacris crucifer, Lithobates catesbeianus and Lithobates clamitans) that are often classified as grazers or detritivores. Tadpoles and potential food sources were sampled in four ponds in southern Illinois and analysed for fatty acid composition. Single linkage cluster analysis was then used to compare fatty acid profiles among tadpole gut contents, tadpole muscle tissues and available food resources. 3.,Diets varied among species and within species among ponds, but organic sediments consistently contributed most to the fatty acid composition of the gut contents of all species. Fatty acid profiles also indicated that larval insects and phytoplankton were consumed by both L. catesbeianus and L. clamitans in one pond, while L. clamitans and P. crucifer consumed mainly periphyton along with sediments in another pond, and these diet differences appeared linked to physical differences among ponds, with periphyton and/or phytoplankton contributing more to tadpole diets in less shaded ponds. 4.,The fatty acid composition of muscle tissues of L. clamitans, the dominant tadpole in these systems, indicated that plant detritus and bacteria, which were the dominant components of organic sediments in the ponds, were common components of the assimilatory diet. 5.,Results demonstrate the utility of fatty acid analyses for assessing both consumption and assimilation. The tadpole assemblages we examined derive much of their energy from heterotrophic and allochthonous sources and exhibit high dietary plasticity. This information will allow for more accurate and comprehensive assessments of trophic interactions in freshwater habitats, as well as aid in amphibian conservation, management and captive propagation efforts. [source] First laboratory confirmation of Xylophilus ampelinus in Slovenia,EPPO BULLETIN, Issue 1 2005T. Dreo Bacterial blight of grapevine is caused by a slow-growing bacterium Xylophilus ampelinus. It has been suspected to occur in Slovenia on the basis of visual observation of characteristic symptoms in the 1960s. In the present study, symptoms were recorded in an infected vineyard during three consecutive years (2002/2004). Samples from this vineyard were tested by nested-PCR and isolation of bacteria on media was attempted. In the first year, angular lesions on leaves were highly expressed and an isolate morphologically similar to X. ampelinus was obtained from one sample. It was purified and identified as X. ampelinus using biochemical and nutritional tests, fatty acid analysis, immuno-fluorescence, nested PCR and partial sequencing of the 16S rRNA gene. The 16S rDNA sequence showed 99,100% homology to known sequences of X. ampelinus strains, including the type strain. Pathogenicity of the isolate was confirmed in tissue-cultured and potted grapevine plants. In the following two years, symptoms of bacterial blight were only faintly expressed. Using isolation on media and nested-PCR, 23 and 17 extracts prepared from 10 and 8 grapevines, respectively, were analysed. In 2003, no positive sample was found, but X. ampelinus was again isolated and identified by colony morphology and nested-PCR in 2004. [source] Diversity of soil mycobacterium isolates from three sites that degrade polycyclic aromatic hydrocarbonsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007C.D. Miller Abstract Aims:, This paper investigates the diversity of polycyclic aromatic hydrocarbon (PAH)-degrading mycobacterium isolates from three different sites within United States: Montana, Texas and Indiana. Methods and Results:, All five mycobacterium isolates differed in chromosomal restriction enzyme-fragmentation patterns; three isolates possessed linear plasmids. The DNA sequence between the murA and rRNA genes were divergent but the sequence upstream of nidBA genes, encoding a dioxygenase involved in pyrene oxidation, was more highly conserved. Long-chain fatty acid analysis showed most similarity between three isolates from the same Montana site. All isolates were sensitive to rifampicin and isoniazid, used in tuberculosis treatment, and to syringopeptins, produced by plant-associated pseudomonads. Biofilm growth was least for isolate MCS that grew on plate medium as rough-edged colonies. The patterns of substrate utilization in Biolog plates showed clustering of the Montana isolates compared with Mycobacterium vanbaalenii and Mycobacterium gilvum. Conclusion:, The five PAH-degrading mycobacterium isolates studied differ in genetic and biochemical properties. Significance and Impact of the Study:, Different properties with respect to antibiotic susceptibility, substrate utilization and biofilm formation could influence the survival in soil of the microbe and their suitability for use in bioaugmentation. [source] Identification and serotyping of atypical Legionella pneumophila strains isolated from human and environmental sourcesJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007J.H. Helbig Abstract Aims:, To validate identification methods for Legionella pneumophila strains that cannot be serotyped into the known serogroups and to characterize their antigenic diversity. Methods and Results:, Fifty L. pneumophila strains that could not be serogrouped, but which had been confirmed as L. pneumophila by mip gene sequencing, were further identified phenotypically. We used (i) MONOFLUO anti- Legionella Staining Reagent (Bio-Rad) (50/50), (ii) an in-house prepared immunoblot assay for the detection of L. pneumophila - specific Mip protein epitope (50/50), (iii) fatty acid analysis using the Microbial Identifications System (MIDI) (47/50) and (iv) Oxoid agglutination tests (44/50). The serological diversity was further characterized by testing with five serogroup-cross-reactive monoclonal antibodies, resulting in nine phenons. Conclusions:, The division of L. pneumophila into 15 serogroups does not reflect the serogroup heterogeneity. Results of these tests indicate that there are more serogroups. Significance and Impact of the Study:, MONOFLUO anti- Legionella Staining Reagent is the only commercially available tool for identifying atypical strains of L. pneumophila. If necessary for epidemiological purposes, the antigenic heterogeneity of these strains can be analysed by monoclonal antibodies. [source] Characterization of micro-organisms isolated from dairy industry after cleaning and fogging disinfection with alkyl amine and peracetic acidJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2005E. Bore Abstract Aims:, To characterize micro-organisms isolated from Norwegian dairy production plants after cleaning and fogging disinfection with alkyl amine/peracetic acid and to indicate reasons for survival. Methods and Results:, Microbial samples were collected from five dairy plants after cleaning and fogging disinfection. Isolates from two of these production plants, which used fogging with alkylamino acetate (plant A), and peracetic acid (plant B), were chosen for further characterization. The sequence of the 16S ribosomal DNA, fatty acid analysis and biochemical characteristics were used to identify isolates. Three isolates identified as Rhodococcus erythropolis, Methylobacterium rhodesianum and Rhodotorula mucilaginosa were isolated from plant A and one Sphingomonas sp. and two M. extorquens from plant B. Different patterns of resistance to seven disinfectants in a bactericidal suspension test and variable degree of attachment to stainless steel were found. The strains with higher disinfectant resistance showed lower degree of attachment than susceptible strains. Conclusions:, The study identifies and characterizes micro-organisms present after cleaning and fogging disinfection. Both surface attachment and resistance were shown as possible reasons for the presence of the isolates after cleaning and disinfection. Significance and Impact of the Study:, These results contribute to the awareness of disinfectant resistance as well as attachment as mechanisms of survival in dairy industry. It also strengthens the argument of frequent alternation of disinfectants in the food processing industry to avoid the establishment of resistant house strains. [source] Role of Alicyclobacillus acidoterrestris in the development of a disinfectant taint in shelf-stable fruit juiceLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2003N. Jensen Abstract Aims: This study was undertaken to identify the bacterium and metabolic products contributing to a disinfectant taint in shelf-stable fruit juice and to determine some of the growth conditions for the organism. Methods and Results: Microbiological examination of tainted and untainted fruit juice drinks detected low numbers of acid-dependent, thermotolerant, spore-forming bacteria in the tainted juices only. The presence of ,-cyclohexyl fatty acids was confirmed in two of the isolates by cell membrane fatty acid analysis. The isolates were subsequently identified as Alicyclobacillus acidoterrestris by partial 16S rDNA sequencing. Studies on the isolates showed growth at pH 2·5,6·0 and 19·5,58 °C. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify 2,6-dibromophenol (2,6-DBP) and 2,6-dichlorophenol (2,6-DCP) in the tainted juice. Challenge studies in a mixed fruit drink inoculated with the two isolates and the type strain of A. acidoterrestris, incubated at 44,46 °C for 4 d, showed the production of both metabolites, which were confirmed and quantified by GC/MS. Conclusions: The results show that A. acidoterrestris can produce 2,6-DBP and 2,6-DCP in shelf-stable juices. Significance and Impact of the Study: This is the first report detailing experimental methodology showing that A. acidoterrestris can produce 2,6-DCP in foods. Control of storage temperatures (to <,20 °C) immediately after processing may provide an effective control measure for the fruit juice industry to prevent spoilage by A. acidoterrestris. [source] Proximate composition, fatty acid analysis and protein digestibility-corrected amino acid score of three Mediterranean cephalopodsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 10 2006Spiros Zlatanos Abstract Proximate composition, fatty acid analysis and protein digestibility-corrected amino acid score (PDCAAS) in three commercially important cephalopods of the Mediterranean sea (cuttlefish, octopus and squid) were determined. The results of the proximate analysis showed that these species had very high protein:fat ratios similar to lean beef. Docosahexaenoic, palmitic and eicosipentaenoic acid were the most abundant fatty acids among analyzed species. The amount of n- 3 fatty acids was higher than that of saturated, monounsaturated and n- 6 fatty acids. Despite the fact that cephalopods contain small amounts of fat they were found quite rich in n- 3 fatty acids. Finally, PDCAAS indicated that these organisms had a very good protein quality. [source] Bacterial leaf blight of strawberry (Fragaria (x) ananassa) caused by a pathovar of Xanthomonas arboricola, not similar to Xanthomonas fragariae Kennedy & King.PLANT PATHOLOGY, Issue 6 2001Description of the causal organism as Xanthomonas arboricola pv. fragariae (pv. nov., comb. nov.) A new bacterial disease of strawberry is described. This disease, called bacterial leaf blight of strawberry, is characterized by dry, brown necrotic leaf spots and large brown V-shaped lesions along the leaf margin, midrib and major veins. Symptoms are different from angular leaf spot of strawberry caused by the bacterium Xanthomonas fragariae. Strains of the bacterial leaf blight pathogen were characterized in a polyphasic approach by biochemical tests, fatty acid analysis, protein electrophoresis, serology, PCR, pigment analysis, ice-nucleation activity, AFLP analysis, DNA:DNA hybridization, pathogenicity and host range tests, and compared with a number of reference strains of X. fragariae and other Xanthomonas species. Bacterial leaf blight strains formed a homogeneous group in all tests, completely different from X. fragariae. They were the only strains causing leaf blight of strawberry upon artificial inoculation into strawberry. Fatty acid and protein electrophoretic analysis showed that the strains belong to the phenon X. campestris (sensu latu, including pathovars now classified as belonging to X. arboricola). AFLP analysis and DNA:DNA hybridization further clarified their taxonomic position as belonging to X. arboricola. The name X. arboricola pv. fragariae is proposed for the bacterium causing leaf blight of strawberry with strain PD2780 (LMG 19145) as pathovar type strain. Criteria for routine identification are given and the taxonomic status is discussed. [source] Characterization of extracellular polymers synthesized by tropical intertidal biofilm bacteriaJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007B.O. Ortega-Morales Abstract Aim:, This study was performed to determine the potential of tropical intertidal biofilm bacteria as a source of novel exopolymers (EPS). Methods and Results:, A screening procedure was implemented to detect EPS-producing biofilm bacteria. Isolates MC3B-10 and MC6B-22, identified respectively as a Microbacterium species and Bacillus species by 16S rDNA and cellular fatty acids analyses, produced different EPS, as evidenced by colorimetric and gas chromatographic analyses. The polymer produced by isolate MC3B-10 displays significant surfactant activity, and may chelate calcium as evidenced by spectroscopic analysis. Conclusions:, Polymer MC3B-10 appears to be a glycoprotein, while EPS MC6B-22 seems to be a true polysaccharide dominated by neutral sugars but with significant concentrations of uronic acids and hexosamines. EPS MC3B-10 possesses a higher surfactant activity than that of commercial surfactants, and given its anionic nature, may chelate cations thus proving useful in bioremediation. The chemical composition of polymer MC6B-22 suggests its potential biomedical application in tissue regeneration. Significance and Impact of the Study:, This is the first report of a Microbacterium species producing EPS with surfactant properties, which expands our knowledge of the micro-organisms capable of producing these biomolecules. Furthermore, this work shows that tropical intertidal environments are a nonpreviously recognized habitat for bioprospecting EPS-producing bacteria, and that these molecules might be involved in ecological roles protecting the cells against dessication. [source] | ||||||||||||||||||||||