Plant growth regulators and amino acids released by Azospirillum sp in chemically defined media

AIMS: To investigate the ability of Azospirillum sp., a facultative endophitic diazotrophic bacterium, to release plant growth regulators (PGR) such as polyamines, ethylene, indoleacetic acid and amino acids in both combined-N and N-free cultures. METHODS AND RESULTS: The presence of those substances was analysed by HPLC. Azospirillum sp. is capable of releasing PGR and amino acids into the culture medium. CONCLUSIONS: The type and quantity of the released substances varied, depending on the presence of combined-N in the medium. SIGNIFICANCE AND IMPACT OF THE STUDY: A better knowledge of PGR produced by Azospirillum sp. has been gained.     

The role of kairomones in prey finding by Diomus sp. and Exochomus sp., two coccinellid predators of the cassava mealybug, Phenacoccus manihoti

We studied searching behaviour of Diomus sp., a coccinellid predator introduced into Africa as a natural enemy of the cassava mealybug, when searching on cassava leaves, and compared its behaviour with the searching behaviour of Exochomus sp., an African predator of mealybugs (MB's). Female adults of Diomus and Exochomus spent more time searching on cassava leaves previously infested with cassava MB than on clean cassava leaves, in response to substances produced by MB's (wax and/or honeydew) still present on these leaves as kairomones after removal of the MB's. Both species were also arrested by wax and/or honeydew of the citrus mealybug, Planococcus citri. When offered a choice between kairomones of both MB species only experienced Diomus (reared on cassava MB) showed a clear preference for kairomone of cassava MB. Separate influences of wax and honeydew were tested. Wax from cassava MB was an arrestment stimulus for both coccinellid species. Honeydew produced by cassava MB arrested Exochomus and inexperienced Diomus.

---

Zusammenfassung Das Suchverhalten auf Cassaveblätter des coccinelliden Raübers Diomus, eines aus Süd Amerika importierten natürlichen Feindes der Cassaveschmierlaus wurde studiert und verglichen mit dem Suchverhalten eines afrikanischen Räubers von Schmierläusen, Exochomus sp.. Weiblichen Adulten von Diomus un Exochomus verwendeten mehr Zeit auf Cassaveblätter wenn diese Blätter vorher mit Cassaveschmierläuse infiziert waren als auf uninfizierte Blätter, und gebrauchten Substanzen (Wachs und/oder Honigtau) die von Schmierläuse produziert wurden und nach der Entfernung der Schmierläuse auf die Blätter zugeblieben waren als Kairomonen.Beide Arten wurden auch von Wachs und/oder Honigtau der Citrusschmierlaus, Planococcus citri, auf den Blätter arretiert. Wenn die Tiere wahlen könnten zwischen Kairomone der beiden Schmierlausarten wurden die Kairomonen der Cassaveschmierlaus nur von erfahrenen Diomus-Individuen, die auf Cassaveschmierlaüse aufgezogen wurden, bevorzugt.Die Einflüsse von Wachs und Honigtau wurden separat geprüft. Wachs von Exuvien der Cassaveschmierlaus ist ein Arretierungsstimulus für beide Räuberarten. Von Cassaveschmierläusen produzierten Honigtau arretierte Exochomus-und unerfahrene Diomus-Individuen.

     

Prey selection by a stonefly: the influence of hunger and prey size

Summary The influences of hunger and prey size on prey selection by the stonefly Hesperoperla pacifica (Perlidae) were explored in the laboratory by observing behavioral responses toward ten prey taxa and three nonprey taxa. Patterns of behavior were consistent with most assumptions and predictions of optimal foraging theory predicting sizebased prey selection by pursuing predators. Handling time appeared to increase as an exponential function of prey mass, and prey profitability (mg/s) was highest for small and intermediate-sized prey. Fasted stoneflies consumed a wide range of prey sizes, whereas well-fed stoneflies concentrated their attacks on intermediate-sized prey. Responses of H. pacifica to nonprey taxa, however, suggest that prey recognition and selection are not based on size alone.     

Overriding the oddity effect in mixed-species aggregations: group choice by armored and nonarmored prey

Because "odd" individuals often suffer disproportionately highrates of predation, solitary individuals should join groupswhose members are most similar to themselves in appearance.We examined group-choice decisions by individuals in armoredand nonarmored species and predicted that either (1) the oddityeffect would result in preference for conspecific groups forsolitary individuals of both species, or (2) individuals inthe armored species would prefer to associate with groups containingindividuals of the more vulnerable species. Armored brook sticklebacks(Culaea inconstans) and nonarmored fathead minnows (Pimephalespromelas) have the same predators and often occur together instreams. In mixed-species shoals, yellow perch (Perca flavescens)attacked minnows earlier and more often than sticklebacks. Wetested whether solitary minnows and sticklebacks preferred toassociate with conspecific or heterospecific shoals under conditionsof both low and high predation risk. When predation risk washigh, minnows preferred to associate with conspecifics overheterospecifics, as predicted by the oddity effect. In contrast,sticklebacks preferentially associated with groups of minnowsover groups of conspecifics when predation risk was high. Whenpredation risk was low, solitary individuals of both speciespreferentially associated with conspecific over heterospecificshoals. Stickleback shoal choices under low-risk conditionsmay have been influenced by interspecific competition for food.In feeding experiments, minnows were more efficient foragersthan sticklebacks, so it should benefit sticklebacks to avoidminnows unless predation risk is high. Therefore, for armoredprey, the benefits of associating with more vulnerable preyappear to override the costs of both the oddity effect and foodcompetition when predation risk is high.     

Prey location,biomechanical constraints,and motor program choice during prey capture in the tomato frog, <Emphasis Type="Italic">Dyscophus guineti</Emphasis>

This study investigated how visual information about prey location and biomechanical constraints of the feeding apparatus influence the feeding behavior of the tomato frog, Dyscophus guineti. When feeding on prey at small azimuths (less than ± 40°), frogs aimed their heads toward the prey but did not aim their tongues relative to their heads. Frogs projected their tongues rapidly by transferring momentum from the lower jaw to the tongue. Storage and recovery of elastic energy by the mouth opening muscles amplified the velocities of mouth opening and tongue projection. This behavior can only occur when the lower jaw and tongue are aligned (i.e., within the range of motion of the neck). When feeding on prey at large azimuths (greater than ± 40°), frogs aimed both the head and tongue toward the prey and used a muscular hydrostatic mechanism to project the tongue. Hydrostatic elongation allows for frogs to capture prey at greater azimuthal locations. Because the tongue moves independently of the lower jaw, frogs can no longer take advantage of momentum transfer to amplify the speed of tongue projection. To feed on prey at different azimuthal locations, tomato frogs switch between alternative strategies to circumvent these biomechanical constraints.     

Visual and olfactory location of biotopes, prey patches, and individual prey by the ladybeetleChilocorus nigritus

Foraging behaviour of the predatorChilocorus nigritus (Fabricius) (Coleoptera: Coccinellidae) at the three spatial levels of biotope, prey patch and individual prey, was studied in the laboratory, and related to behaviour in the field. Vertically oriented parallel lines were more attractive than the same shapes in a horizontal position. A simulated horizon with a tree line was preferred to a simulated flat horizon. They were attracted to a tree image for the first 2 h of exposure, but were less attracted after longer exposure, possibly due to habituation. Leaf shape was recognised, and simple ovate leaves were preferred to compound bipinnate leaves and to squares. These responses were associated with biotope selection for feeding and aggregation at aestivation sites. The location of prey patches by adults involved prey odour but the location of such sites by larvae did not. Adults detected individual prey visually and olfactorily over short distances but physical contact with prey was required for detection by larvae. Location of individual prey and prey patches by adults and larvae was facilitated by alternation between intensive and extensive search. The differences in the ability of larvae and adults to locate prey, stem from the adults being the active locators of biotope and patch, whereas the comparatively immobile larvae depend on their parents’ ability for long-range location of prey. Two hypotheses concerning coccinellid foraging behaviour are proposed. Firstly, the duration of response to a visual cue is related to the distance over which such a cue may be perceived. It follows that habituation to closer range cues occurs more rapidly than to longer range cues. Secondly, visual cues used by adults at the different spatial levels of prey location, and the location of mates and aggregation sites, have the same or similar shape. These results also provide guidelines for orchard management to maximise the biocontrol value of this species.     

The composition of the proteinaceous polysaccharides exuded by astragalus microcephalus,A. Gummifer and A. Kurdicus—The sources of turkish gum tragacanth

Gum tragacanth is a variable commodity because commercial samples may legitimately be admixtures, in any relative proportions, of the exudates from Asiatic Astragalus spp. Analytical data show that the exudates collected from the three major contributing Turkish spp., A. microcephalus, A. gummifer and A. kurdicus, differ extensively, particularly in terms of their fucose, xylose, galacturonic acid and methoxyl contents and in the relative proportions of their soluble (tragacanthin) and insoluble (bassorin) components. In addition, these three Astragalus exudates are shown to be proteinaceous polysaccharides; their amino acid compositions differ, particularly in terms of their hydroxyproline, histidine, aspartic acid and arginine content. In contrast, the amino acid compositions of the soluble and insoluble components of A. kurdicus do not differ extensively.     

Degradation of proteins during the fermentation of African locust bean (Parkia biglobosa) by strains of Bacillus subtilis and Bacillus pumilus for production of Soumbala

AIMS: To examine isolates of Bacillus subtilis and B. pumilus predominant in Soumbala for their ability to degrade African locust bean proteins (ALBP). METHODS AND RESULTS: Agar diffusion test in casein and ALBP agar was used for screening of isolates. The profiles of water-soluble proteins and free amino acids (FAA) during the fermentation of ALBP by the Bacillus isolates were studied by SDS-PAGE and cation exchange chromatography. The profile of soluble proteins changed with the fermentation time and varied depending on the isolate. The quantity of total FAA and essential FAA such as lysine was increased sharply between 24 and 48 h of fermentation and differed among the isolates. Simultaneously, a pH increase was observed. Cysteine, methionine, leucine, isoleucine, tyrosine and phenylalaline appeared during fermentation. CONCLUSION: The Bacillus isolates studied degraded ALBP leading to a profile of soluble proteins and FAA specific for each isolate. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to the selection of Bacillus strains to be used as starter cultures for controlled production of Soumbala.     

Gustatory discrimination of sugars, amino acids, and selected allelochemicals by the tarnished plant bug, Lygus lineolaris

ABSTRACT. Selected sugars, amino acids and allelochemicals were tested over a range of concentrations to determine their effect on the ingestion rates of adult tarnished plant bugs. Experiments were performed with a two-choice bioassay technique utilizing artificial membranes. Sucrose was the most effective feeding stimulant of all the compounds tested. Glucose was an effective stimulant but was 8 times less potent than sucrose. Fructose was 50 times less potent than sucrose. Methionine and phenylalanine were the only amino acids of seven tested which stimulated feeding. Leucine produced a deterrent effect. Cotton tannin was the most effective deterrent of all allelochemicals tested and was 10 times more potent than gossypol. The quinone, 1, 4-napthoquinone, and the alkaloid, tomatine, were also effective feeding deterrents. Sinigrin and its aglycone, ethyl isothiocyanate, were among the weakest deterrents of all the allelochemicals tested. Hydroquinone was the least potent deterrent of all compounds tested. The results indicate a strong chemosensory component regulating the feeding response of the tarnished plant bug. It is suggested that this response is mediated by epipharyngeal chemosensitive sensilla.     

Genetic diversity and divergence of the endangered freshwater goby Rhinogobius sp. BB in Okinawa Island

The genetic diversity and population structure of Rhinogobius sp. BB, the fluvial landlocked endangered goby, were investigated and were compared with those of the closely related amphidromous Rhinogobius sp. MO at 11 microsatellite loci. Specimens of Rhinogobius sp. BB were collected from the Genka and Takae-A rivers, and those of Rhinogobius sp. MO were collected from the Genka and Suginda rivers in Okinawa Island. At 11 microsatellite loci, the two populations of Rhinogobius sp. BB showed lower variation than the two Rhinogobius sp. MO populations: the average number of alleles was 3.6 and 2.0 vs. 8.6 and 7.6, respectively; and the observed heterozygosity was 0.263 and 0.281 vs. 0.440 and 0.545, respectively. Pairwise F_st tests showed significant differences (P < 0.001) among the populations: F_st was 0.525 between the two Rhinogobius sp. BB populations, 0.079 between the two Rhinogobius sp. MO populations, and varied from 0.456 to 0.462 for comparisons among Rhinogobius sp. BB and MO. Nei’s genetic distance between the two Rhinogobius sp. BB populations is extremely large (0.604) compared with that between the two Rhinogobius sp. MO populations (0.126). The two populations of Rhinogobius sp. BB are genetically divergent, and they have extremely low genetic diversity. Therefore, the conservation of Rhinogobius sp. BB in Okinawa Island requires the assessment of each river’s population.     

Identification and quantitative determination of eudesmane-type acids from the essential oil of Dittrichia viscosa sp. viscosa using 13C-NMR spectroscopy

A procedure that allows the identification and quantitative determination of eudesmane-type acids in the acidic part of the essential oil of Dittrichia viscosa sp. viscosa is described. The method involves the computer-aided analysis of the 13C-NMR spectrum of the mixture without the requirement of previous separation or derivatisation. The quantitative procedure was verified with costic acid standard and applied to three other acids which possess the same eudesmane framework.     

Specific effects by the psychotomimetic drugsd-amphetamine and phencyclidine on the performance of an aversely motivated successive visual discrimination in the rat

Summary Rats were trained to perform a conditioned avoidance response to white noise in a conventional two-compartment shuttle-box. The partition between the compartments had two openings, however, and the correct passage (leftor right) was signalled by changes in background illumination. In this situation the psychotomimetic compoundsd-amphetamine (4 mg kg^–1 IP) and phencyclidine (PCP) (2 mg kg^–1 SC) were found to selectively disrupt the visual discrimination. Thed-amphetamine-induced abnormal behavior in this situation has previously been linked to excessive dopamine (DA) receptor stimulation, not controlled by nerve impulse flow and its regulation by important local feed-back mechanisms. Thus, the psychotomimetic effects produced by this compound should not only by due to increased DA receptor activationper se, but also to a disruption of normal patterns of firing and release in dopaminergic neurons. There is evidence to suggest that PCP via an excitatory amino acid (EAA) receptor produces a similar net effect on brain meso-limbic dopaminergic neurotransmission via an increased rate of firing, accompanied by regularization of firing (loss of burst activity). In support for a mediation of PCP-induced effects via EAA receptors, the local application of kynurenic acid into the ventral forebrain (4.7µg, bilaterally) was found also to produce a selective disruption of discriminative performance. It should be noted, however, thatd-amphetamine-induced loss of discriminative behavior, but not that induced by PCP, was antagonized by haloperidol (0.1–0.2 mg kg^–1 IP) administration. It is thus possible that at least some effects of PCP in this situation are mediated on the efferent side of the dopaminergic neuron. It is suggested that the abnormal behavior, as evidenced by a loss of discriminative (but not avoidance) behavior, is due to disruption of normal, feed-back regulated, nerve impulse flow.     

Predicting acidic and alkaline enzymes by incorporating the average chemical shift and gene ontology informations into the general form of Chou's PseAAC

Knowledge of the adaptation mechanism of enzymes to extreme pH values and distinguishing them from one another are necessary in the proteomics field, and would help in the drug design of stable enzymes. In this work, we have systematically analyzed the information of 105 acidic and 112 alkaline enzymes, and propose an approach for distinguishing acidic enzymes from alkaline enzymes by combining the amino acid composition, reduced amino acid composition, gene ontology, evolutionary information, and auto covariance of averaged chemical shift (acACS). The overall prediction accuracy is 94.01% by 10-fold cross-validation using the algorithm of support vector machine. This result is better than that obtained by other existing methods. The improvement of the overall prediction accuracy reaches up to 3.3% higher than those of the random forest algorithm and secondary structure amino acid composition. The acACS performance is excellent, indicating that our approach is better than other existing methods in the literature. A user-friendly web-server pred-enzymes for predicting acidic and alkaline enzymes has been established, which is accessible to the public.     

Rapid Determination of Norepinephrine, Dopamine, Serotonin, Their Precursor Amino Acids, and Related Metabolites in Discrete Brain Areas of Mice Within Ten Minutes by HPLC with Electrochemical Detection

A rapid and simple chromatographic procedure using HPLC with electrochemical detection is described for simultaneous determination of the substrates from precursor amino acids to metabolites related to synthesis and metabolism of three monoamine neurotransmitters--norepinephrine (NE), dopamine (DA), and 5-hydroxytryptamine (5-HT, serotonin)--in discrete brain areas of the mouse. Under the present instrumental and mobile phase conditions, the procedure permits simultaneous determination of three monoamines (NE, DA, and 5-HT), two precursor amino acids (tyrosine and tryptophan), and four respective metabolites (3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid) within 10 min in one chromatographic run. By varying column temperature, this procedure also permits simultaneous determination of 10-14 monoamine-related substrates including the nine substrates described above within 15-21 min. The validity of the present procedure is demonstrated by analyzing the effect of an alpha 2-adrenergic agonist (clonidine) and an alpha 2-antagonist (yohimbine) in mouse hypothalamus.     

Different Changes in Concentrations of Monoamines and Their Metabolites and Amino Acids in Various Brain Regions by the Herbal Medicine/Toki-Shakuyaku-San Between Female and Male Senescence-Accelerated Mice (SAMP8)

Due to it's estrogen-secreting qualities, a Japanese herbal medicine, Toki-Shakuyaku-San may have a potential role for Alzheimer's disease in women. The effect of treatment with Toki-Shakuyaku-San testing on concentrations of monoamines, their metabolites and amino acids in the cortex, hippocampus and striatum of senescence accelerated mice (SAMP8) was examined and sex differences of SAMP8 and ddY mice was studied. In the female SAMP8, concentrations of -aminobutyric acid, alanine, and glycine were elevated in three regions after treatment. The concentration of glutamate was decreased in the cortex, hippocampus, and striatum of female and male SAMP8 and not in female and male ddY mice. These results suggest that different effects of Toki-Shakuyaku-San treatment on concentrations of monoamines, their metabolites and amino acids in the brain tissue may be due to its stimulation of secreted estrogen on neurons.     

The uptake of copper ions by cell suspension cultures of Agave amaniensis,and its effect on the growth,amino acids and hecogenin content

Cell suspension cultures of Agave amaniensiswere able to grow in media containing 10 – 240 M copper ions, and could remove more than 67% copper ions from the media. The cells accumulated up to 106 mg g^–1 copper ions in the biomass. Copper ions at 240 M caused a decrease in growth index and packed cell volume of the cultures of 61.5 and 53.3%, respectively. The presence of copper ions caused the cell walls to thicken and to be more wrinkled. Certain amino acids were released in high concentration into the media. The hecogenin content in the biomass increased up to 157.9% at 20 M copper ions.     

4,5-dihydroxypipecolic acids in the seed of Julbernardia,Isoberlinia and Brachystegia

2(S)-carboxy-4(R),5(R),-dihydroxypiperidine has been isolated from seed of Julbernardia paniculata. The distribution of non-protein amino acids in the genera Julbernardia, Isoberlinia, Brachystegia and Cryptosepalum is also reported.     

Cloning of the wide spectrum amidase gene from Brevibacterium sp. R312 by genetic complementation. Overexpression in Brevibacterium sp. and Escherichia coli

Abstract The amiE gene of Brevibacterium sp. R312 encoding wide spectrum amidase was isolated by complementation of a Brevibacterium sp. mutant using a plasmid gene bank of chromosomal DNA. The amiE structural gene and its promoter were localized on a 1.8-kb fragment by subsequent subcloning and complementation studies. In Brevibacterium sp., the investigation of amidase activities related to one copy of the gene suggested that the regulation of the amiE gene expression was under negative control. High expression levels have been obtained in Brevibacterium sp. and, after substitution of the amiE promoter by the tac promoter, in Escherichia coli .     

Extracellular Acidic Sulfur-Containing Amino Acids and γ-Glutamyl Peptides in Global Ischemia: Postischemic Recovery of Neuronal Activity Is Paralleled by a Tetrodotoxin-Sensitive Increase in Cysteine Sulfinate in the CA1 of the Rat Hippocampus

An excessive activation of the excitatory amino acid system has been proposed as one possible mediator of the ischemia-induced delayed death of CA1 pyramidal cells in the hippocampus. Using dialytrodes in the CA1 of the rat, we have investigated multiple-unit activity and extracellular changes in acidic sulfur-containing amino acids and gamma-glutamyl peptides during ischemia (20-min, four-vessel occlusion) and during 8 h of reflow. Multiple-unit activity was abolished during ischemia and for the following 1 h, but then recovered, gradually reaching preischemic levels after 8 h of reflow. Extracellular cysteate, cysteine sulfinate, and gamma-glutamyltaurine increased (1.5- to threefold) during ischemia, and extracellular glutathione and gamma-glutamylaspartate plus gamma-glutamylglutamine increased during early reflow (two- to threefold). The recovery of neuronal activity at 4-8 h was paralleled by an increase in extracellular cysteine sulfinate (2.5-fold at 8 h of reflow). Perfusion with 10 microM tetrodotoxin at 8 h of reflow abolished the multiple-unit activity and reduced extracellular cysteine sulfinate. Considering the glutamate-like properties of cysteine sulfinate, the observed postischemic increase may be involved in the development of the delayed neuronal death.