Olfactory discrimination of complex mixtures of amino acids by the black bullhead Ameiurus melas

On the basis of previous findings of behavioural discrimination of amino acids and on the knowledge of electrophysiology of the catfish (genera Ictalurus and Ameiurus) olfactory organs, behavioural experiments that investigated olfactory discrimination of amino acid mixtures were carried out on the black bullhead Ameiurus melas. Repeated presentations of food‐rewarded mixtures released increased swimming activity measured by counting the number of turns >90° within 90 s of stimulus addition. Non‐rewarded amino acids and their mixtures released little swimming activity, indicating that A. melas discriminated between the conditioned and the non‐conditioned stimuli. Two questions of mixture discrimination were addressed: (1) Are A. melas able to detect components within simple and complex amino acid mixtures? (2) What are the smallest differences between two complex mixtures that A. melas can detect? Three and 13 component mixtures tested were composed primarily of equipotent amino acids [determined by equal electroolfactogram (EOG) amplitude] that contained L‐Cys at ×100 the equipotent concentration. Ameiurus melas initially perceived the ternary amino acid mixture as its more stimulatory component alone [i.e. cysteine (Cys)], whereas the conditioned 13 component mixture containing the more stimulatory L‐Cys was perceived immediately as different from L‐Cys alone. The results indicate that components of ternary mixtures are detectable by A. melas but not those of more complex mixtures. To test for the smallest detectable differences in composition between similar multimixtures, all mixture components were equipotent. Initially, A. melas were unable to discriminate the mixtures of six amino acids from the conditioned mixtures of seven amino acids, whereas they discriminated immediately the mixtures of four and five amino acids from the conditioned mixture. Experience with dissimilar mixtures enabled the A. melas to start discriminating the seven‐component conditioned mixture from its six‐component counterparts. After fewer than five training trials, A. melas discriminated the mixtures of nine and 10 amino acids from a conditioned mixture of 12 equipotent amino acids; however, irrespective of the number of training trials, A. melas were unable to discriminate the 12 component mixture from its 11 component counterparts.     

Studies on aspergilli. VI. The utilization of amino acids in mixtures by some ascosporic members of the aspergillus nidulans group

Summary The utilization of certain amino acids when supplied in three different combinations, (a) glycine, serine, valine, histidine (b) methionine, valine, alanine, arginine (c) leucine, tryptophane, glutamic acid, aspartic acid, byA. nidulans (Eidam)Wint;A. rugulosus Thom andRaper;A. variecolor (Berk. andBr.)Thom andRaper;A. quadrilineatus Thom andRaper andA. violaceus Fennel andRaper was studied through circular partition chromatography. It was found that these Aspergilli which are so closely related morphologically exhibited different rate of assimilation of amino acids. Amino acids in mixtures were utilized better than when supplied singly. Although different species had their own preference to certain amino acids yet there was a simultaneous utilization of both good and poor amino acids.     

Structure-function relationships of the antibacterial activity of phenolic acids and their metabolism by lactic acid bacteria

Aims: To determine structure–function relationships of antibacterial phenolic acids and their metabolites produced by lactic acid bacteria (LAB). Methods and Results: Minimum inhibitory concentrations (MICs) of 6 hydroxybenzoic and 6 hydroxycinnamic acids were determined with Lactobacillus plantarum, Lactobacillus hammesii, Escherichia coli and Bacillus subtilis as indicator strains. The antibacterial activity of phenolic acids increased at lower pH. A decreasing number of hydroxyl groups enhanced the activity of hydroxybenzoic acids, but had minor effects on hydroxycinnamic acids. Substitution of hydroxyl groups with methoxy groups increased the activity of hydroxybenzoic, but not of hydroxycinnamic, acid. Metabolism of chlorogenic, caffeic, p‐coumaric, ferulic, protocatechuic or p‐hydroxybenzoic acids by L. plantarum, L. hammesii, Lactobacillus fermentum and Lactobacillus reuteri was analysed by LC‐DAD‐MS. Furthermore, MICs of substrates and metabolites were compared. Decarboxylated and/or reduced metabolites of phenolic acids had a lower activity than the substrates. Strain‐specific metabolism of phenolic acids generally corresponded to resistance. Conclusions: The influence of lipophilicity on the antibacterial activity of hydroxybenzoic acids is stronger than that of hydroxycinnamic acids. Metabolism of phenolic acids by LAB detoxifies phenolic acids. Significance and Impact of the Study: Results allow the targeted selection of plant extracts for food preservation, and selection of starter cultures for fermented products.     

Chemical Composition and Content of Lipophilic Seed Extractives of Some Abies and Picea Species

The chemical content and composition of the lipophilic extracts from seeds of some fir species: Abies alba, A. cephalonica, A. concolor, and A. koreana, as well as of a few spruce species: Picea abies, P. orientalis, and P. pungens, were examined. The amount of lipophilic extractives is diverse among the tree species and it varies from 9.8% to 41% of seeds. The chemical characterization showed significant differences, not only in the content, but also in the composition of extractives. However, most of the identified compounds like resin alcohols, ‐aldehydes, and ‐acids, as well as fatty acids, were detected in the seed extracts of all the examined tree species. The dominating identified compound group was esterified fatty acids (2.5 – 55.4% w/w of dry extract), occurring mainly as tri‐ and diglycerides, as well as free acids. The main representatives of this group were linoleic and oleic acids. The resin acids, among which the main were abietic, neoabietic, dehydroabietic, and palustric acids, were also detected at high levels, from 1.8% to 16.9% of the dry seed extracts. Phytosterols, tocopherols, resin hydrocarbons, and resin esters, as well as fatty alcohols were also identified. The coniferous tree seeds, as a renewable natural material, could represent a prospective raw material for producing valuable chemicals.     

Alteration of free amino acid concentrations in insect galls induced by Andricus mukaigawae (Hymenoptera; Cynipidae)

1. Insect galls are abnormal plant growths that develop in response to a stimulus provided by a galling insect. The nutrition hypothesis suggests that the concentrations of nutritive compounds in galls are changed to provide optimum nutrition for the larvae and adults of galling insects. 2. To test the nutrition hypothesis, we determined the concentrations of 20 free amino acids in galls and in galled and ungalled twigs of Quercus fabri during the larval and adult stages of Andricus mukaigawae using high-performance liquid chromatography with ultraviolet–visible detection. 3. At the larval stage, the concentrations of 12 out of 20 amino acids in A. mukaigawae galls were significantly higher than those in galled and ungalled twigs. Asparagine and tryptophan were the most abundant nonessential and essential amino acids, respectively, in A. mukaigawae galls. 4. At the adult stage, the concentrations of most amino acids, except proline, were significantly lower in A. mukaigawae galls than in galled and ungalled twigs. The A. mukaigawae adults may not manipulate amino acid levels because the adults do not feed on galls. The decrease of amino acid levels in adult galls may be viewed as a depletion. 5. The composition of free amino acids in A. mukaigawae galls was significantly different from the composition in galled and ungalled twigs in both the larval and adult stages. 6. Our results may support the nutrition hypothesis. We suggest that a high concentration of proline in A. mukaigawae galls may protect larvae and adults from plant defense responses.     

湖南道地白芷氨基酸含量与组成分析

白芷是我国常用中药材的一种,关于白芷镇痛的有效成分,主要认为是异欧前胡素、欧前胡素等香豆素类具有解痉、镇痛等作用的挥发油类化学成分,但白芷镇痛的成分及其机理尚不十分清楚,是否有其他物质也具有一定的药理作用也不得而知,比如说某些药效性氨基酸。该研究采用自动氨基酸分析仪测定了湖南道地茶陵白芷的蛋白质类氨基酸和游离氨基酸的含量,并分析其氨基酸组成。结果表明:总氨基酸检出除Asn以外的其他16种蛋白质氨基酸,含量最高的Arg占总氨基酸的31.21%,接近1/3;必需氨基酸总量达27.01%,其中含量最高的是Leu,占总必需氨基酸的24.14%;药效氨基酸比例较高,在酸水解产物总氨基酸和游离氨基酸中分别达到73.89%和85.78%,其中Arg的含量最高,达1.383g·100g-1,占比为42.24%,游离氨基酸中γ-氨基丁酸、鸟氨酸含量也较高。此外,还含有少量的高半胱氨酸和鹅肌肽等游离非蛋白质氨基酸和短肽;必需氨基酸的组成接近WHO/FAO的建议摄入值,但Met+Cys的RC值最小,为第一限制性氨基酸。这些药效性氨基酸和游离氨基酸可能是茶陵白芷具有良好药效的一个因素,而且茶陵白芷的氨基酸组成和配比较合理、符合人体需要,在强化含硫氨基酸的基础上具有开发成为新型药食同源保健性食品的潜力。研究结果可为进一步研究白芷的药理作用提供依据。     

Quantitative determination of flavonoid content in the aerial part of Baical scullcap (<Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi)

A pharmacognostic study of aerial parts of Scutellaria baicalensis Georgi (Lamiaceae family) has been carried out. A merchandising analysis has been performed to determine the basic quality parameters of S. baicalensis. A chemical composition analysis has revealed the presence of organic acids, free carbohydrates, polysaccharides, amino acids, alkaloids, flavonoids, phenolic acids, anthocyanins, tannins, photosynthetic pigments, lipids, and triterpene compounds. Ethyl acetate and ethanol fractions, extracted from the aerial parts of S. baikalensis, have shown a significant antiradical activity.     

Actinoplanic acids A and B as novel inhibitors of farnesyl-protein transferase

Actinoplanic acids A and B are macrocyclic polycarboxylic acids that are potent reversible inhibitors of farnesyl-protein transferase. Actinoplanic acids A and B were isolated from Actinoplanes sp. MA 7066 while actinoplanic acid B was isolated from both MA 7066 and Streptomyces sp. MA 7099. Actinoplanic acids A and B are competitive with respect to farnesyl diphosphate and are selective inhibitors of farnesyl-protein transferase because they do not inhibit geranylgeranyl-protein transferase type 1 or squalene synthase. MA 7066 is believed to be a novel species of actinomycetes while MA 7099 is believed to be a novel strain of Streptomyces violaceusniger on the basis of morphological, biochemical and chemotaxonomic characteristics as well as its production of actinoplanic acids.     

Chaetomella acutiseta produces chaetomellic acids A and B which are reversible inhibitors of farnesyl-protien transferase

Chaetomellic acids A and B, isolated from Chaetomella acutiseta, are specific inhibitors of farnesyl-protein transferase that do not inhibit geranylgeranyl transferase type 1 or squalene synthase. Chaetomellic acids A and B are reversible inhibitors, resemble farnesyl diphosphate and probably inhibit FPTase by substituting for farnesyl diphosphate. Chaetomellic acid production appears to be widespread within the genus Chaetomella. Correspondence to: R. B. Lingham     

Chemotaxonomy of planktonic cyanobacteria based on non-polar and 3-hydroxy fatty acid composition

Twenty-eight axenio planktonic cyanobacterial strains (10 Microcystis, three Oscillatoria, one Spirulina, one Aphanizomenon, 13 Anabaena) were investigated for their fatty acid composition by measurement of non-polar and hydroxy fatty acids. No 2-hydroxy fatty acids were detected in any strain, but 3-hydroxy fatty acids were detected in minor quantities in 24 strains. The highest portion of total fatty acids were non-polar fatty acids. Qualitative and quantitative analyses of 3-hydroxy fatty acids showed no taxonomic value in these strains, while the type of non-polar fatty acid composition was shown to be consistent within Microcystis and Anabaena strains, distinguishing them as type 4, characterized by the presence of 18:4, and type 2, characterized by 18:3 (α) of the Kenyon-Murata system. Two Oscillatoria agardhii Gomont strains were also included in the type 2 group due to the presence of 18: 3 (α), but the difference in characteristics of 16:2 and 16:3 between O. agardhii and Anabaena further divided type 2 into two subgroups: type 2A for Anabaena and type 2B for O. agardhii. A simplified unweighted pair group method with arithmetic averages (UPGMA) dendrogram demonstrated that the classification of 28 strains (Microcystis spp., Anabaena spp., Aphanizomenon flos-aquae (Lemmermann) Ralfs f. gracile (Lemmermann) Elenkin, O. agardhii and Spirullnasubsalsa Oersted ex Gomont based on numerical analysis of non-polar fatty acids corresponded to morphological species criteria, suggesting that non-polar fatty acid composition is a valuable chemical marker in the taxonomy of planktonic cyanobacteria. However, the fatty acid composition in Oscillatoria raciborskii is similar to that of Microcystis and very different from that of O. agardhii, suggesting its special position in Oscillatoria and the chemical diversity in the genus Oscillatoria.     

Competition between cis,trans and Cyclopropane Fatty Acid Formation and its Impact on Membrane Fluidity

The impact of cis, trans and cyclopropane fatty acids on membrane fluidity was investigated using batch‐grown Pseudomonas putida P8 and Comamonas testosteroni ATCC 17454. A major difference observed between the two investigated strains is the absence of the ability to synthesize trans‐unsaturated fatty acids in Comamonas. When grown exponentially at 30 °C, a shift to 35 °C increased the trans/cis ratios of the fatty acids of P. putida P8 from 0 to 0.81 and 0 to 1.07, in lipid extracts and cell hydrolyzates, respectively. After prolonged growth followed by nutrient deprivation for 48 h, both at 30 °C, trans fatty acids were absent, but the cyclo/cis ratios rose from 0.1 to 1.55 in lipid extracts, and from 0.1 to 1.54 in cell hydrolyzates. C. testosteroni ATCC 17454 contained no cyclo fatty acids when harvested in the exponential phase after 6 h, whereas after 72 h cultivation, the cyclo/cis ratios rose to 0.49 and 0.47, in lipid extracts and cell hydrolyzates, respectively. Trans fatty acids were never observed in this strain. Increased cyclo/cis and trans/cis ratios correlated with decreased fluidity measured by the fluorescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) intercalated in the bilayers of liposomes and by Fourier Transform Infrared (FTIR) spectroscopy of lipids prepared from the cells. The specific effect of cyclopropane fatty acids on membrane fluidity was much smaller than that of trans fatty acids. FTIR‐measurements of intact cells of P. putida P8 confirmed the high potency of trans fatty acids to decrease the fluidity. In cells with induced cyclopropane fatty acid synthesis, the membranes remained more fluidized, indicating the lower importance of these fatty acids for homeoviscosis.     

Anti-cyanobacterial fatty acids released from <Emphasis Type="Italic">Myriophyllum spicatum</Emphasis>

This study was carried out to identify unknown allelochemicals released from Myriophyllum spicatum and to investigate their anti-cyanobacterial effects. A series of analyses of culture solutions and methanol extracts of M. spicatum using gas chromatograph equipped with a mass selective detector revealed that M. spicatum released fatty acids, specifically, nonanoic, tetradecanoic, hexadecanoic, octadecanoic, and octadecenoic acids. Nonanoic, cis-6-octadecenoic, and cis-9-octadecenoic acids significantly inhibited growth of Microcystis aeruginosa, whereas tetradecanoic, hexadecanoic, and octadecanoic acids did not show any effect. When the inhibitory effect of nonanoic acid was compared with those of 4 polyphenols and eugeniin, which are anti-cyanobacterial compounds previously reported to be released by M. spicatum, nonanoic acid was found to be the most inhibitory to M. aeruginosa. These results indicate that not only polyphenols and eugeniin but also fatty acids such as nonanoic acid must be studied to reveal how M. spicatum exerts its allelopathic effect on M. aeruginosa.     

Ultrastructure and lipid chemistry of specialized epidermal structure of Indian porcupines and hedgehog

Poddar‐Sarkar, M., Raha, P., Bhar, R., Chakraborty, A. and Brahmachary, R.L. 2011. Ultrastructure and lipid chemistry of specialized epidermal structure of Indian porcupines and hedgehog. —Acta Zoologica (Stockholm) 92 : 134–140. In the present study, we investigated the ultrastructural variations of specialized epidermal structure of Indian porcupines (Hystrix indica and Atherurus macrourus) and hedgehog (Hemiechinus collaris) as well as the variation in the fatty acid composition of total lipid fraction. Scanning electron microscope images reveal the usual scaly structure in surface view and network of channels in cross‐section but with different orientation of partition walls. The lipid profile reveals the presence of free sterol, long‐chain alcohol, free fatty acids, wax ester and sterol ester in all the three cases and trace amount of triglyceride, diglyceride and monoglyceride. Gas chromatography–mass spectrometry analysis of fatty acid methyl ester of total lipid fraction indicates the presence of C₈‐C₂₂ fatty acids in Hystrix indica, C₈‐C₁₈ in Atherurus macrourus and C₈‐C₂₀ fatty acids in Hemiechinus collaris. It is interesting to note that the total lipid fraction of hedgehog shows no branched‐chain, unsaturated and odd‐carbon fatty acids. Odd‐carbon fatty acid and branched‐chain fatty acids detected in the adult H. indica but were absent in juvenile H. indica as well as in A. macrourus. With the exception of C_18:1, the other unsaturated fatty acids were also absent in both juvenile H. indica and A. macrourus.     

Purification and properties of d-hydantoin hydrolase and N-carbamoyl-d-amino acid amidohydrolase from Flavobacterium sp. AJ11199 and Pasteurella sp. AJ11221

We characterized recombinant d-hydantoin hydrolase (DHHase) and N-carbamoyl-d-amino acid amidohydrolase (DCHase) from Flavobacterium sp. AJ11199 and Pasteurella sp. AJ11221. The DHHases from these two strains showed a wide range of hydrolytic activity for various 5-monosubstituted d-hydantoin compounds, including a very high level activity for d-hydantoin compounds corresponding to d-aromatic amino acids such as d-tryptophan d-phenylalanine and d-tyrosine. The DCHases, in turn, were capable of catalyzing the hydrolysis of various N-carbamoyl-d-amino acids (NCD-A.A.) corresponding to d-aliphatic and d-aromatic amino acids. The combination of these enzymes was found to be applicable for the production of various d-amino acids.     

Cloning and Sequencing of Alginate Lyase Genes from Deep-Sea Strains of Vibrio and Agarivorans and Characterization of a New Vibrio Enzyme

Four alginate lyase genes were cloned and sequenced from the genomic DNAs of deep-sea bacteria, namely members of Vibrio and Agarivorans. Three of them were from Vibrio sp. JAM-A9m, which encoded alginate lyases, A9mT, A9mC, and A9mL. A9mT was composed of 286 amino acids and 57% homologous to AlxM of Photobacterium sp. A9mC (221 amino acids) and A9mL (522 amino acids) had the highest degree of similarity to two individual alginate lyases of Vibrio splendidus with 74% and 84% identity, respectively. The other gene for alginate lyase, A1mU, was shotgun cloned from Agarivorans sp. JAM-A1m. A1mU (286 amino acids) showed the highest homology to AlyVOA of Vibrio sp. with 76% identity. All alginate lyases belong to polysaccharide lyase family 7, although, they do not show significant similarity to one another with 14% to 58% identity. Among the above lyases, the recombinant A9mT was purified to homogeneity and characterized. The molecular mass of A9mT was around 28 kDa. The enzyme was remarkably salt activated and showed the highest thermal stability in the presence of NaCl. A9mT favorably degraded mannuronate polymer in alginate. We discussed substrate specificities of family 7 alginate lyases based on their conserved amino acid sequences.     

The critical role of His48 in mouse cytosolic sulfotransferase SULT2A8 for the 7α-hydroxyl sulfation of bile acids

Members of the cytosolic sulfotransferase (SULT) SULT2A subfamily are known to be critically involved in the homeostasis of steroids and bile acids. SULT2A8, a 7α-hydroxyl bile acid-preferring mouse SULT, has been identified as the major enzyme responsible for the mouse-specific 7-O-sulfation of bile acids. Interestingly, SULT2A8 lacks a conservative catalytic His residue at position 99th. The catalytic mechanism underlying the SULT2A8-mediated 7-O-sulfation of bile acids thus remained unclear. In this study, we performed a mutational analysis in order to gain insight into this yet-unresolved issue. Results obtained revealed two amino acid residues, His48 and Leu99, that are unique to the mouse SULT2A8, but not other SULTs, are essential for its 7-O-sulfating activity toward bile acids. These findings suggested that substitutions of two amino acids, which might have occurred during the evolution of the mouse SULT2A8 gene, endowed mouse SULT2A8 the capacity to catalyze the 7-O-sulfation of bile acids.     

Lipid Fatty Acid Composition and Thermophilicity of Cyanobacteria

An analysis of lipid fatty acid composition in several unicellular and filamentous forms of mesophilic and thermophilic cyanobacteria was performed. At 47°C (the temperature of thermophilic cyanobacteria maintenance in the collection), the unicellular thermophilic Synechococcus strains were devoid of polyenoic acids as distinct from the mesophilic forms of this genus at the temperature of 20°C (the temperature of this cyanobacterial maintenance in the collection). In the thermophilic Synechococcus elongatusIPPAS B-267 strain, a decrease in temperature did not result in the occurrence of C18 polyenoic acids, but the quantitative relationship between the saturated and unsaturated fatty acids (S/U ratio) was decreased twofold. In contrast, the culturing of mesophilic strains at 25–32°C resulted in an increase in the S/U ratio due to an increase in the proportion of the 16:0 acid. In the Synechococcus IPPAS B-434 strain, this treatment resulted in a decrease in the relative content of monoenoic, mainly hexadecenoic, acids. The cyanobacterium Gloeobacter violaceus, which lacks thylakoids, and whose photosystems are formed in a cell membrane, contained polyenoic acids. The filamentous thermophilic cyanobacterium Phormidium laminosum, at the maintenance temperature of 47°C, did contain polyenoic acids, but their proportion was considerably lower than that in the filamentous mesophilic forms, such as Tolypothrix sp. and Spirulina platensis. A relative content of hexadecenoic acids in Ph. laminosum was higher than in the mesophilic forms. A possible role of hexadecenoic acids in the processes of adaptation of cyanobacteria to high temperatures is discussed. A relationship between the characteristics of fatty acid composition fixed by evolution and the changes caused by adaptation to a particular environment is considered.     

Effect of frozen storage on fatty acid composition of the different tissues of four scombrid and one dussumeriid species

In the current study, the effect of frozen storage at ?18°C was evaluated on fatty acid composition of different body parts (liver, muscle tissue, and viscera) of narrow‐barred Spanish mackerel (Scomberomorus commerson, Lacépède, 1800), longtail tuna (Thunnus tonggol, Bleeker, 1851), kawakawa (Euthynnus affinis, Cantor, 1849), king mackerel (Scomberomorus guttatus, Bloch & Schneider, 1801), and rainbow sardine (Dussumieria acuta, Valenciennes, 1847) caught in the Persian Gulf. Changes in saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid plus docosahexaenoic acid/palmitic acid (EPA+DHA/C16), ω3 PUFA/ω6 PUFA (ω3/ω6), and polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) were investigated during a 6‐month period. A decrease in unsaturated fatty acids, particularly PUFAs (60–100%) as well as ω3/ω6, EPA+DHA/C16 (polyene index) and PUFA/SFA ratios, indicated a decrease in the nutritional values of the samples.