Taste receptor stimulation and feeding behaviour in the puffer, Fugu pardalis I. Effect of single chemicals

In electrophysiological experimentation, various chemicals areeffective in stimulating the lip chemoreceptors of the puffer,Fugu pardalis (Hidaka et al., 1975; Kiyohara et al., 1975a).Their effects as feeding stimulants on this fish were studiedby offering the lip stimulants in starch pellets. The starchpellet by itself was not taken by the fish but it was acceptedwhen stimulants such as clam extracts were addded to it. Sucrose,ineffective as a lip chemoreceptor stimulant, had no effecton feeding behaviour. NaCl, to which the lip chemoreceptorsshow a low sensitivity, did not affect the feeding responsewhen added at 2 M to clam extracts. HCl and quinine inhibitedthe response of the fish to the clam extracts. Alanine and otheramino acids, which were effective on the lip chemoreceptors,were accepted. AMP, IMP, UMP and ADP were not accepted in spiteof their marked stimulatory effectiveness on the lip chemoreceptors.Sodium salts of fumaric, malic and succinic acids were not accepted.     

Heavy metal complexation in polluted molluscs II. Oysters (Ostrea edulis and Crassostrea gigas)

Cadmium, zinc and copper, accumulated from polluted habitats by the oysters Ostrea edulis and Crassostrea gigas, were studied. Three distinct low molecular weight (less than 3000 daltons) zinc complexes were separated from highly contaminated C. gigas, one of which may be a complex with the amino acid taurine. Only one of these zinc complexes was present in less contaminated specimens of O. edulis. On gel permeation chromatography of oyster extracts, copper was eluted together with amino acids (principally taurine) and the betaine homarine. No evidence of metallothionein type proteins was found.     

Evaluation of methods for the separation and analysis of proteins and free amino acids in phytoplankton samples

Due to their importance as not only major constituents in paniculatematter but also the metabolism of nitrogen in marine microorganisms,numerous methods have been employed to measure proteins andfree amino acids. However, two difficulties frequently complicatethese measurements. First, an initial separation of proteinsfrom free amino acids is helpful since most analytical methodsare somewhat sensitive to both compound types. Second, the choiceof detection techniques that minimize response differences betweenvarious proteins or amino acids is desirable since natural samplesof microorganisms consist of mixtures of many proteins and aminoacids. To address these problems, four protein detection techniques(modified Lowry et al., Dorsey et al., Bradford and fluorescamine)and two amino acid detection techniques (fluorescamine and o-phthaldialdehyde)were evaluated. Relative extraction efficiencies for proteinfrom phytoplankton samples were also evaluated with six homogenizationsolutions/protocols (TCA, NaOH, boiling NaOH, Triton X-100,NaOH plus Triton X-100 and distilled water). TCA homogenizationyielded the highest protein recoveries, and sufficient physicalseparations between proteins and free amino acids were obtainedwith TCA concentrations between 0.18 and 0.37 M. Results ofthese studies allowed for development of a method for extracting,separating and analyzing proteins and total free amino acidsfrom a common phytoplankton sample. The procedure involves initialhomogenization in a TCA solution, followed by centrifugationto separate protein and free amino acid fractions. Proteinsare then analyzed by a modification of the Lowry et al. procedure,and amino acids by a fluorescamine procedure. ²Present address: Science Applications International Corporation,4224Campus Point Court, San Diego, CA 92121, USA     

Role of amino acids, betaine and choline in vitamin B12 biosynthesis by strains of Propionibacterium

This paper reports the role of amino acids, betaine and choline on vitamin B₁₂ biosynthesis in Propionibacterium shermanii 566, P. shermanii and Propionibacterium arl AKU 1251. l-Glutamic acid supplemented at the 0.05% (w/v) level in whey permeate stimulated vitamin B₁₂ production in the three organisms, whereas the influence of other amino acids differed in the three strains. A uniform increase in product formation in Propionibacterium cultures with increasing doses of betaine and choline was recorded, but with variable relative effectiveness. However, no significant difference at the 0.50 and 0.75% (w/v) levels of these two compounds was observed. The addition of betaine at 0.5% (w/v) concentration was considered optimal for maximum fermentation efficiency in the cultures. An increase of 2.8–25.7% and 5.1–40.8% in vitamin B₁₂ yield as compared to the control was observed by supplementing whey permeate medium with l-glutamic acid and betaine, respectively, at their optimum values in the organisms studied.     

Delimitation of Epacridaceae: Preliminary Molecular Evidence

Comparative sequence data for the chloroplast encodedrbc L genehas been obtained for species representing the basal lineagesin the proposed phylogeny of Powellet al. (Annals of Botany77:305–315, 1996), with the aim of testing the delimitationof the family and the validity of the supra-generic taxa proposed,and estimating relationships within the family. Cladistic analysesindicate that EpacridaceaesensuPowellet al. (1996) is not monophyletic.Lebetanthus,a monotypic genus from South America commonly placed withinthe family, mostly near the Tasmanian endemicPrionotes, is shownto be closer toGaultheriaand other members of the ericaceoustribe Andromedeae. The hypothetical phylogeny of Powellet al.(1996) is evaluated in the light of this preliminary analysisof relationships within the family. The data do not supportthe recognition of the two subfamilies, Richeoideae and Epacridoideae,of Watson Epacridaceae; Ericales; molecular systematics; molecular systematics; rbc L     

Foliar Uptake and Movement of Chlormequat in Cereals: Influence of Dose and Addition of Related Chemicals

Increased amounts of chlormequat applied to leaves of barleyand wheat resulted in a greater proportion being taken up andmoving to the tips of treated leaves. Combined foliar applicationwith certain other amines also increased uptake and movementof chlormequat - choline and glycine betaine were particularlyeffective - but a few others had the reverse effect. Ammoniumand sodium salts of acetic, butyric and hydrochloric acids alsoincreased movement of ¹⁴C-chlormequat Hordeum vulgare L., barley, Triticum aestivum L., wheat, chlormequat, foliar uptake     

Chemical stimulants of cheliped flexion behavior by the Western Atlantic ghost crab Ocypode quadrata (Fabricius)

Cheliped flexion behavior was used as a bioassay to measure the responses of the Western Atlantic ghost crab Ocypode quadrata (Fabricius) to pure and natural stimuli. Responses to mantle fluid of Geukensia demissa Dillwyn are based on heat stable components of < 1000 mol. wt. In each class of pure compounds the following were most stimulatory: butanoic acid, carboxylic acids; trehalose, carbohydrates; homarine, amines; asparagine, amino acids. The response to butanoic acid was the largest of any stimulus tested. Disaccharides were more stimulatory than their common monosaccharide component, glucose, and were significantly more potent than amines, except for homarine. Disaccharides, carboxylic acids, and most of the amines were significantly more stimulatory than any of the amino acids. Proteins were the least stimulatory in contrast to the tripeptide glutathione that elicited responses similar to amino acids. These chemical stimuli are components of both live and decomposing foods in the diet of this species. The wide response spectrum of this species may reflect its “plasticity” of foraging behavior     

Effects of Salinity on Metabolic Profiles, Gene Expressions, and Antioxidant Enzymes in Halophyte Suaeda salsa

Halophyte Suaeda salsa is native to the saline soil in the Yellow River Delta. Soil salinity can reduce plant productivity and therefore is the most important factor for the degradation of wetlands in the Yellow River Delta. In this work we characterized the salinity-induced effects in S. salsa in terms of metabolic profiling, antioxidant enzyme activities, and gene expression quantification. Our results showed that salinity inhibited plant growth of S. salsa and upregulated gene expression levels of myo-inositol-1-phosphate synthase (INPS), choline monooxygenase (CMO), betaine aldehyde dehydrogenase (BADH), and catalase (CAT), and elevated the activities of superoxide dismutase (SOD), peroxidase (POD), CAT, and glutathione peroxidase (GPx). The significant metabolic responses included the depleted amino acids malate, fumarate, choline, phosphocholine, and elevated betaine and allantoin in the aboveground part of S. salsa seedlings as well as depleted glucose and fructose and elevated proline, citrate, and sucrose in root tissues. Based on these significant biological markers, salinity treatments induced clear osmotic stress (for example, INPS, CMO, BADH, betaine, proline) and oxidative stress (for example, SOD, POD, CAT, GPx activities), disturbed protein biosynthesis/degradation (amino acids and total protein) and energy metabolism (for example, glucose, sucrose, citrate) in S. salsa.     

Changes in Amino-acid Content of Tomato Xylem Sap Following Infection with Strains of Verticillium albo-atrum

Xylem exudates of four tomato cultivars showing resistance andsusceptibility to the vascular pathogen Verticillium albo-atrum,were analysed for amino acids and amides by column chromatography42 days after inculation with different isolates of the fungus.Analysis of the exudate from healthy, resistant Loran Bloodshowed a substantial reduction in amino compounds compared withthe healthy, susceptible Potentate and Bonny Best. ResistantMoscow, however, gave similar results to Potentate. Infectionin all cultivars except Moscow led to a general increase inthe concentration of amino acids and predominantly in asparticand glutamic acids, threonine, serine, proline, tyrosine, ornithine,lysine, histidine, and phenylalanine. A reduction in prolinecontent of up to 90 per cent occurred in the resistant plantsin both pathogenic and non-pathogenic combinations. The resultsare discussed in relation to previously published data on vascularcolonization and disease development with the same tomato cultiversand fungal strains.     

Effect of photoinhibition on algal photosynthesis: a dynamic model

Recent evidence from algal physiology and molecular biologyconfirms that photoinhibition is directly related to D1 proteindamage and recovery, and D1 protein damage leads to a decreasein electron transfer or an increase in turnover time of theelectron transfer chain. In this study, the turnover time ofthe electron transfer chain is defined as a function of therelative concentration of D1 protein in reaction centre II andthe photoinhibition processes due to D1 protein degradationare incorporated into a model of photosynthesis, initiated byDubinsky et al. (Plant Cell Physiol., 27, 1335–1349, 1986)and developed by Sakshaug et al. (Limnol. Oceanogr., 34, 198–205,1989). D1 protein damage is assumed to be both light and D1protein concentration dependent, and to be proportional to thecross-section of PSII (     

野蚕黑卵蜂寄主识别利它素的纯化及氨基酸组成分析

针对利它素特殊的物理及化学性质,采用特定的温度分离方法,成功地从野蚕Theophila mandarina和家蚕Bombyx mori的雌蛾性附腺中分别获得了纯度较高的野蚕黑卵蜂Telenomus theophilae寄主识别利它素。对这两种利它素氨基酸组成的分析表明,来自家蚕和野蚕雌蛾性附腺的利它素在氨基酸的组成和含量方面非常相似,在检测到的15种氨基酸中,甘氨酸、谷氨酸和天冬氨酸的克分子百分数在10%以上。从家蚕得到的分别为28.1%、18.5%和12.6%。从野蚕得到的分别为24.4%、18.1%和10.1%。这3种氨基酸之和在家蚕和野蚕中均超过50%以上。用凝胰乳蛋白酶对这两种利它素进行水解时发现溶液中均产生非水溶性沉淀,电泳表明沉淀的多肽蛋白分子量在10 Kd左右。这显示在野蚕和家蚕利它素结构中,有着与家蚕丝蛋白相类似的结构,存在着结晶区域（沉淀）和无定形区域（上清）。     

Studies in the biochemistry of cirripede eggs. IV. The free Amino-acid pool in the eggs of Balanus balanoides (L.) and B. balanus (L.) during development

Changes in the ‘free’ amino acids, betaine, and trimethylamine oxide during the development of the eggs of Balanus balanoides (L.) and B. balanus (L.) have been determined; the results are given in terms of μM/g dry wt, μM/g water, and μM/10⁶ eggs. The amino acids are derived from the yolk proteins the net composition of which is known. Free amino acids are present in considerable quantity, as is commonly the case with crustacean tissue. Changes in the individual amino acids are discussed. B. balanus eggs contain large, and relatively constant, amounts of sarcosine; its function is unknown but large quantities are present in the more highly evolved cirripedes so far examined. A possible relation between betaine glycine, and sarcosine relative to choline metabolism is considered. Large amounts of taurine are present. There is a striking increase in β-alanine in the late stages of development; in B. balanoides it comes to be the most, and in B. balanus the third most common amino acid; its possible involvement in purine metabolism is considered. The relation between the amounts of the various entities in the eggs and in the bodies of the adult are examined.     

Reserve Mobilization During Germination of Tagetes minuta L.

Levels of albumins, globulins and starch were measured in dryTagetes minuta L. achenes (seeds) germinating at 25 °C andin those thermo-inhibited at 35 °C. In addition, the compositionof amino acids, fatty acids and free sugars was determined. In germinating seeds, albumins increased, while globulins decreased.At 35 °C, only a delayed decrease in globulins occurred.However, in both, the amino acids serine and glutamate increased.Lipid composition remained constant except for a slight declinein linoleic acid in the germinating seeds. At 25 °C, starchlevels increased with time while at 35 °C, there was onlya transient increase. Sucrose was the major free sugar foundin the seeds at all times, but its levels declined in the germinatingseeds. This was accompanied by an increase in the proportionsof glucose and fructose. No such changes in sugar compositionwere observed in the thermo-inhibited seeds. Tagetes minuta L., seed germination, reserve mobilization, thermo-inhibition     

Salt Tolerance in the Halophyte, Suaeda maritima (L.) Dum.: The Influence of the Salinity of the Culture Solution on the Content of Various Organic Compounds

Plants of the halophyte Suaeda maritima were grown in tap wateror in a culture solution in the presence or absence of sodiumchloride and the levels of sugars, amino acids, organic acidsand quaternary ammonium compounds determined in relation tothe balance between cytoplasmic and vacuolar water potentials.The sugar content (some 7 µmol. g f. wt^–1) was unaffectedby the salinity of the growth medium as was the overall contentof amino acids (about 4 µmol. g f. wt^–1). The organicacid content was maximal in plants kept in tap water alone wherethe dominant acid was malic. Plants grown in culture solutioncontained the same acids, although addition of sodium chlorideto the medium brought about the apparent loss of glycolic acidand the appearance of oxalic acid. Only a single quaternaryammonium compound, glycinebetaine, was apparently present inthe tissues: the content of betaine doubled (to 37·5µrmol. g f. wt^–) when sodium chloride was addedto the culture solution. The content of these various compoundsis discussed in relation to the relative values of the cytoplasmicand vacuolar components of the overall tissue water potential Suaeda maritima, halophyte, salt tolerance, betaine, organic compounds, water potential     

Minerals, Carbohydrates and Amino Acids of Pollens from some Woody and Herbaceous Plants

The mineral, carbohydrate, protein, amino acid, lipid and energycontents of the seven main pollens gathered by honey-bees insouth-east Scotland were determined. Neither dry matter (mean73 per cent) nor ash (mean 3 per cent) were very variable. Thecalcium content of all pollens was relatively similar as werethe magnesium, potassium and sodium contents but manganese whichwas relatively high in ericaceae and phosphorus which was lowin Trifolium were more variable. Acer pollen contained mostprotein and Fagus least, and of the amino acids only serine,cystine and histidine were significantly different in the differentpollens. Over 30 per cent of all pollens was a mixture of fructoseand glucose, ericaceae containing most and Acer least. Hemicellulose(mean 7 per cent) was high in Ranunculus and low in Acer, cruciferaeand Fagus. ‘Cellulose’ (mean 0•5 per cent)was high in cruciferae and low in ericacea. Ether extract (mean5 per cent) was high in cruciferae and Fagus. The mean grossenergy of pollen was 23 kJ g^–1. Fresh pollen is comparable with lean meat as a source of energyand protein, and is more like dormant plant seeds than herbagein its water, ash and protein content but stores energy as sugarrather than starch or lipid.     

The analysis of the betaine homarine by high pressure liquid chromatography

A procedure is presented which is suitable for the qualitative and quantitative analysis of the betaine homarine in aqueous tissue extracts. After preliminary purification of the extract by gel permeation chromatography on Sephadex G-25, quantitative analysis of the homarine content is performed by high pressure liquid chromatography on a 1-m column of Corasil II.     

Lipid and Fatty-acid Composition of Diatoms

The lipids and fatty acids of two freshwater diatoms Nitzschiapalea Kutz, Navicula muralis Lewin, and one marine species,Navicula incerta Grun. have been studied. The major lipid components in all species were triglycerides,monogalactosyl, digalactosyl and sulphoquinovosyl diglycerides,phosphatidyl glycerol, phosphatidyl choline (lecithin), andphosphatidyl ethanolamine; while palmitoleic, palmitic, eicosapentaenoicand eicosate-traenoic acids were the major fatty acid constituents.The two galactolipids, monogalactosyl and digalactosyl diglyceridescontained large amounts of C₁₆ and C₂₀ polyunsaturated fattyacids. Lipids of diatoms, whether grown in the light or in the dark,were the same apart from quantitative differences. More storagelipids such as triglycerides were synthesized in the light thanin the dark.     

Isolation and Characterization of the Olfactory Epithelial Cells of the Catfish

A preparation enriched in olfactory receptor cells has beenobtained from the olfactory mucosa of the catfish (Ictaluruspunctatus). The tissue was treated successively with trypsin,DNase, trypsin inhibitor, EDTA in Ca^{+ +} , Mg^{+ +} free mediumaccording to a method derived from that of Cohen, et al.⁽¹⁾.After mechanical disruption of the isolated olfactory lamellae,the cells were isolated by centrifugation on a Ficoll gradient.Each type of cell was morphologically identified by comparingin situ and in vitro preparations by SEM. Small round cellswere collected on 10% Ficoll. The nature of these cells is notknown but part of them are certainly basal cells which havebeen shown⁽²⁾ to be the precursors of the constantly regeneratingolfactory neurons. Respiratory cells settled mainly on 20% Ficoll.A fraction containing 60% sustentacular cells was collectedon 33% Ficoll. Olfactory cells characterized by an axon, a dendriteand several cilia, were found on 37% Ficoll. This fraction alsocontains up to 40% sustentacular cells. A yield of 20% was measuredfor olfactory cell isolation. Vital staining and ability tosynthesize RNA indicate a viability of the final preparationof 70% to 80%. Further identification of the cells was performedby measuring the binding activity of a series of amino acidsto a preparation enriched in olfactory cells. A good correlationwas determined between the extent of the binding and the reportedelectrophysiological activities of these amino acids recordedin vivo. Although the final olfactory cell suspension is notpure, it constitutes the first step in the study of the olfactoryreceptor sites.     

Osmoregulation in Rhodobacter sphaeroides.

Betaine (N,N,N-trimethylglycine) functioned most effectively as an osmoprotectant in osmotically stressed Rhodobacter sphaeroides cells during aerobic growth in the dark and during anaerobic growth in the light. The presence of the amino acids L-glutamate, L-alanine, or L-proline in the growth medium did not result in a significant increase in the growth rate at increased osmotic strengths. The addition of choline to the medium stimulated growth at increased osmolarities but only under aerobic conditions. Under these conditions choline was converted via an oxygen-dependent pathway to betaine, which was not further metabolized. The initial rates of choline uptake by cells grown in media with low and high osmolarities were measured over a wide range of concentrations (1.9 microM to 2.0 mM). Only one kinetically distinguishable choline transport system could be detected. Kt values of 2.4 and 3.0 microM and maximal rates of choline uptake (Vmax) of 5.4 and 4.2 nmol of choline/min.mg of protein were found in cells grown in the minimal medium without or with 0.3 M NaCl, respectively. Choline transport was not inhibited by a 25-fold excess of L-proline or betaine. Only one kinetically distinguishable betaine transport system was found in cells grown in the low-osmolarity minimal medium as well as in a high-osmolarity medium containing 0.3 M NaCl. In cells grown and assayed in the absence of NaCl, betaine transport occurred with a Kt of 15.1 microM and a Vmax of 3.2 nmol/min . mg of protein, whereas in cells that were grown and assayed in the presence of 0.3 M NaCl, the corresponding values were 18.2 microM and 9.2 nmol of betaine/min . mg of protein. This system was also able to transport L-proline, but with a lower affinity than that for betaine. The addition of choline of betaine to the growth medium did not result in the induction of additional transport systems.