Morning glory as a powerful model in ecological genomics: tracing adaptation through both natural and artificial selection

Many diverse questions in ecology and evolution have been addressed using species belonging to the genus Ipomoea, commonly referred to as the morning glory genus. Ipomoea exhibits a wide range of diversity in floral color, growth form, mating system and tolerance to environmental factors, both within and among species, and as such has been a focal group of many investigations in the last 80 years. In this review, we highlight recent work to which Ipomoea species have contributed-from studies of the mating system, molecular evolution, plant-herbivore and plant-parasite interactions to their impact on and importance to agriculture. Genomic resources for this group are currently under development, and given the breadth of studies and history of this group, combined with an expanding genetics toolkit, we argue that Ipomoea should provide the next model organism for ecological genomics.     

Morning glory systemically accumulates scopoletin and scopolin after interaction with Fusarium oxysporum

An isolate of non-pathogenic Fusarium, Fusarium oxysporum 101-2 (NPF), induces resistance in the cuttings of morning glory against Fusarium wilt caused by F. oxysporum f. sp. batatas O-17 (PF). The effect of NPF on phenylpropanoid metabolism in morning glory cuttings was studied. It was found that morning glory tissues responded to treatment with NPF bud-cell suspension (108 bud-cells/ml) with the activation of phenylalanine ammonia-lyase (PAL). PAL activity was induced faster and greater in the NPF-treated cuttings compared to cuttings of a distilled water control. High performance liquid chromatography analysis of the extract from tissues of morning glory cuttings after NPF treatment showed a quicker induction of scopoletin and scopolin synthesis than that seen in the control cuttings. PF also the induced synthesis of these compounds at 10(5) bud-cells/ml, but inhibited it at 10(8) bud-cells/ml. Possibly PF produced constituent(s) that elicited the inhibitory effect on induction of the resistance reaction. These compounds could potentially be useful as markers to detect early beginning interactions between Fusarium and morning glory tissues cuttings.     

Phosphoglycerate as a hill oxidant in a reconstituted chloroplast system

The ability of intact chloroplasts to evolve oxygen when illuminated in the presence of 3-phosphoglycerate is lost following osmotic shock but may be largely restored by the addition of ATP, catalytic amount of nicotinamide adenine dinucleotide phosphate, ferredoxin, and a soluble fraction derived from chloroplasts. In the presence of uncoupling agents and ATP, the rate is faster than that supported by intact chloroplasts. In the absence of uncoupling agents, the ATP requirement may be partially met by photophosphorylation.     

Depression screening as a quality indicator

Objective Although practice guidelines for depression screening are evidence based, with their development relying on reviews of controlled studies, their adaptation and use as quality indicators have not been subject to rigorous study. This paper will therefore review the evidence supporting this practice.Methods A rational evaluation was carried out on both controlled studies and other sources of evidence related to the technical, clinical and policy assumptions underlying the use of depression screening guidelines as quality indicators.Results 1) Technical assumptions: depression screening could be used as a quality indicator. Current information technology does not allow accurate determination of who would benefit from being screened, whether they actually were screened, or the optimal percentage that should be screened. 2) Clinical assumptions: depression screening would improve outcomes. The evidence suggests that although depression screening might increase the diagnosis of depression, depressed patients so recognised tend to be less ill, less in need of treatment, or less likely to benefit from treatment, while screening, in the absence of other interventions, does not improve outcomes. 3) Policy assumptions: depression screening should be a focus of quality improvement. However, relative to other preventative measures, depression screening is a low priority. It does not meet usual cost-effectiveness criteria. There are more robust interventions for depression (i.e. collaborative care) that could be a focus of quality improvement efforts.Conclusion Although routine depression screening may be an acceptable practice guideline, its use as a quality measure is not supported.     

Complementarity as a biodiversity indicator strategy

Richness, rarity, endemism and complementarity of indicator taxon species are often used to select conservation areas, which are then assumed to represent most regional biodiversity. Assessments of the degree to which these indicator conservation areas coincide across different taxa have been conducted on a variety of vertebrate, invertebrate and plant groups at a national scale in Britain, Canada, USA and South Africa and at a regional scale in Cameroon, Uganda and the USA. A low degree of spatial overlap among and within these selected indicator conservation areas has been demonstrated. These results tend to suggest that indicator conservation areas display little congruence across different taxa. However, some of these studies demonstrate that many conservation areas for indicator taxa capture a high proportion of non-target species. Thus it appears that indicator conservation areas might sample overall biodiversity efficiently. These indicator conservation areas may, however, exclude species essential for effective conservation, e.g. rare, endemic or endangered species. The present study investigated the value of indicator taxa as biodiversity surrogates using spatial congruence and representativeness of different indicator priority conservation areas. The conservation status of species excluded by the indicator approaches is also assessed. Indicator priority conservation areas demonstrate high land area requirements in order to fully represent non-target species. These results suggest that efficient priority area selection techniques must reach a compromise between maximizing non-target species gains and minimizing land-use requirements. Reserve selection procedures using indicator-based complementarity appear to be approaches which best satisfy this trade-off.     

Tree growth as a meteorological indicator

The effects of meteorologic factors on the woody stem of trees are discussed, chiefly in relation to growth in the southwestern part of the United States. Three rainfall regimes, in a general sense, result in three growth patterns as recorded in growth-layer characteristics. Inter-relationships of these patterns and their vertical migrations (the "Flagstaff effect")are sensitive recorders of changes in rainfall distribution.In detail within a growing season, an interval of low temperature causes growth slowdown or rupture and collapse of cambial initials and recently formed cells. A short dry spell followed by effective rains may cause the formation of intra-annual densewood as well as certain minor features. Growth may come to a halt and be resumed at any time during the year, even into the winter.The "invisible" extensions of arcs and half-lenses of densewood are delicate recorders of interruptions of cambial activity, the absence of cells which failed to enlarge, and the absence of physiological processes involved in maturation.

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Zusammenfassung Die Wirkungen von meteorologischen Faktoren auf den hölzernen Stamm von Bäumen, hauptsächlich in Beziehung zum Wachstum im Südwesten der Vereinigten Staaten, werden besprochen.Drei Niederschlagsarten führen zu 3 Wachstumsformen nach den Eigenarten der Wachstumsschichten. Beziehungen zwischen diesen Formen und ihrer vertikalen Ausbreitung (Flagstaff-Effekt) sind empfindliche Indikatoren für Anderungen der Niederschlagsverteilung. Im einzelnen verursacht innerhalb der Wachstumsperiode ein Intervall niedriger Temperatur Wachstumsverzögerung oder Ruptur und Zusammenbruch der innersten und jüngsten Zellen. Eine kurze Trockenperiode mit nachfolgendem wirksamen Regen kann zur Bildung von zwischenjährlichen Spätholz führen und zu bestimmten kleineren Kennzeichen. Wachstum kann jederzeit während des Jahres zum Stillstand kommen und wieder einsetzen, selbst im Winter. Die unsichtbaren Ausbreitungen von Ringen und"Mönch" aus Spätholz sind feine Zeichen für Pausen der Kambriumaktivität, das Fehlen von Zellen, die sich nicht vergrössert haben und das Fehlen physiologischer, in die Reifung einbezogener Prozesse.

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Resume On discute les répercussions des facteurs météorologiques sur la partie ligneuse des troncs d'arbres et plus spécialement sur son accroissement dans le sudouest des Etats-Unis. En étudiant les caractéristiques des cernes des arbres,on peut mettre en évidence trois régimes différents de précipitations, le mot régime étant alors pris dans son sens le plus large. Les relations existant entre les trois modèles de succession des couches de bois à l'intérieur des cernes et leur étendue dans le sens vertical (effet Flagstaff) forment un enregistrement très sensible des fluctuations de précipitations. En détail et au cours d'une même période de végétation, un intervalle de basses températures cause un ralentissement de la croissance,voire une rupture et un effondrement des cellules nouvellement formées ou du cambium initial. Une courte période sèche suivie de pluies assez abondantes peut provoquer la formation de couches intermédiaires de bois d'automne ainsi que de traits de moindre importance. La croissance peut être interrompue et reprendre à n'importe quel moment de l'année, même en hiver. L'extension "invisible" de cercles complets ou de demilunes de bois d'automne sont de fins enregistrements de l'interruption de l'activité du cambium. Des complications dans le développement de la plante entraîne la formation de cellules qui n'ont pas réussi à grandir ainsi que l'absence de traces laissées par certains processus physiologiques.

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Work supported by the National Science Foundation.     

Tetrazolium salt as a seed germination indicator

A preliminary assessment of 2:3:5-triphenyl tetrazolium chloride as a seed germination indicator has been made by testing wheat, barley, oats, peas and vetches. Results as reliable as actual germination tests have been obtained, and the optimum conditions for testing have been determined. The application of this technique to other seeds is also discussed.     

Dental enamel as a dietary indicator in mammals

The considerable variation in shape, size, structure and properties of the enamel cap covering mammalian teeth is a topic of great evolutionary interest. No existing theories explain how such variations might be fit for the purpose of breaking food particles down. Borrowing from engineering materials science, we use principles of fracture and deformation of solids to provide a quantitative account of how mammalian enamel may be adapted to diet. Particular attention is paid to mammals that feed on 'hard objects' such as seeds and dry fruits, the outer casings of which appear to have evolved structures with properties similar to those of enamel. These foods are important in the diets of some primates, and have been heavily implicated as a key factor in the evolutionary history of the hominin clade. As a tissue with intrinsic weakness yet exceptional durability, enamel could be especially useful as a dietary indicator for extinct taxa.     

ATP as a biomass indicator for closed ecosystems

Nucleotide measurements have been used as biomass indicators in microbial ecology. We report the use of this metric in materially closed, energetically open microbial ecosystems. Our results indicate that: (i) both ATP concentrations and pO2 show an increase from time of closure; (ii) ATP concentrations (0.2 1.2 ng/ml) are approximately 2 3 times higher than open ocean water; (iii) there is an apparent oscillation of ATP concentrations on the order of 50 days; and (iv) within experimental limitations the ratios of ATP concentrations to observed total cell counts is constant.     

t-butyl hydroperoxide-induced perturbations of human erythrocytes as a model for oxidant stress

Erythrocytes were incubated with t-butyl hydroperoxide in the presence and absence of hemoglobin as a model system for oxidative stress and the alterations in the structure and integrity of the membranes were investigated. The results showed that in the presence of hemoglobin a significant modification in the membrane surface charge was induced but no such alteration was observed in peroxidized hemoglobin-free membranes. As increased hemoglobin oxidation occurred in the erythrocytes, membrane lipid peroxidation diminished, suggesting a protective role for methemoglobin in t-butyl hydroperoxide-induced lipid peroxidation. Electrophoresis on polyacrylamide gels showed modification of the cytoplasmic protein region but no high molecular weight aggregates formed at the concentrations of the hydroperoxide used in this work. The results suggest that the t-butyl hydroperoxide/normal erythrocyte system seems to be an instructive model for membrane perturbations characteristic of oxidative disorders.     

Morning floral heat as a reward to the pollinators of the Oncocyclus irises

Relationships between flowering plants and their pollinators are usually affected by the amount of reward, mainly pollen or nectar, offered to pollinators by flowers, with these amounts usually positively correlated with floral display. The large Oncocyclus iris flowers, despite being the largest flowers in the East Mediterranean flora, are nectarless and have hidden pollen. No pollinators visit the flowers during daytime, and these flowers are pollinated only by night-sheltering solitary male bees. These iris flowers are partially or fully dark-colored, suggesting that they gather heat by absorbing solar radiation. Here we test the hypothesis that the dark-colored flowers of the Oncocyclus irises offer heat reward to their male solitary bee pollinators. Floral temperature was higher by 2.5°C than ambient air after sunrise. Solitary male bees emerged earlier after sheltering in Oncocyclus flowers than from other experimental shelter types. Pollination tunnels facing east towards the rising sun hosted more male bees than other aspects. We suggest that floral heat reward can explain the evolution of dark floral colors in Oncocyclus irises, mediated by the pollinators’ behavior.     

Bacterial plasmolysis as a physical indicator of viability.

Bacterial plasmolytic response to osmotic stress was evaluated as a physical indicator of membrane integrity and hence cellular viability. Digital image analysis and either low-magnification dark-field, high-magnification phase-contrast, or confocal laser microscopy, in conjunction with pulse application of a 1.5 M NaCl solution, were used as a rapid, growth-independent method for quantifying the viability of attached biofilm bacteria. Bacteria were considered viable if they were capable of plasmolysis, as quantified by changes in cell area or light scattering. When viable Salmonella enteritidis biofilm cells were exposed to 1.5 M NaCl, an approximately 50% reduction in cell protoplast area (as determined by high-magnification phase-contrast microscopy) was observed. In contrast, heat- and formalin-killed S. enteritidis cells were unresponsive to NaCl treatment. Furthermore, the mean dark-field cell area of a viable, sessile population of Pseudomonas fluorescens cells (approximately 1,100 cells) increased by 50% as a result of salt stress, from 1,035 +/- 162 to 1,588 +/- 284 microns2, because of increased light scattering of the condensed, plasmolyzed cell protoplast. Light scattering of ethanol-killed control biofilm cells underwent little change following salt stress. When the results obtained with scanning confocal laser microscopy and a fluorescent viability probe were compared with the accuracy of plasmolysis as a viability indicator, it was found that the two methods were in close agreement. Used alone or in conjunction with fluorochemical probes, physical indicators of membrane integrity provided a rapid, direct, growth-independent method for determining the viability of biofilm bacteria known to undergo plasmolysis, and this method may have value during efficacy testing of biocides and other antimicrobial agents when nondestructive time course analyses are required.     

Sutural amplitude of ammonite shells as a paleoenvironmental indicator

The Sutural Amplitude Index (SAI), obtained by measuring the maximum height of sutural elements and the length of the suture pattern on ammonoid shells, provides a useful indicator of relative habitat depth for ammonoids with similar shell morphotypes. A higher SAI indicates greater septal support for the shell wall against implosion under increased hydrostatic pressures in deeper waters. Relating the sutural amplitude indices of ammonites found in a well-studied depositional basin, such as the Cretaceous Western Interior Seaway, to morphotype distributions illustrates the utility of this index in bathymetric interpretations. □ Ammonoidea, sutures, Sutural Amplitude Index, Cretaceous, Greenhorn Cyclothem. Western Interior.     

Peroxo-bridged divanadate as selective bromide oxidant in bromoperoxidation

Diperoxovanadate is effective only in presence of free vanadate in vanadium-dependent bromoperoxidation at physiological pH. Peroxide in the form of bridged divanadate complex (VOOV-type), but not the bidentate form as in diperoxovanadate, is proposed to be the oxidant of bromide. In order to obtain direct evidence, peroxo-divanadate complexes with glycyl-glycine, glycyl-alanine and glycyl-asparagine as heteroligands were synthesized. By elemental analysis and spectral studies they were characterized to be triperoxo-divanadates, [V₂O₂(O₂)₃(peptide)₃].H₂O, with the two vanadium atoms bridged by a peroxide and a heteroligand. The dipeptide seems to stabilize the peroxo-bridge by inter-ligand interaction, possibly hydrogen bonding. This is indicated by rapid degradation of these compounds on dissolving in water with partial loss of peroxide accompanied by release of bubbles of oxygen. The ⁵¹V-NMR spectra of such solutions showed diperoxovanadate and decavanadate (oligomerized from vanadate) as the products. Additional oxygen was released on treating these solutions with catalase as expected of residual diperoxovanadate. The solid compounds when added to the reaction mixtures showed transient, rapid bromoperoxidation reaction, but not oxidation of NADH or inactivation of glucose oxidase, the other two activities shown by a mixture of diperoxovanadate and vanadyl. This demonstration of peroxide-bridged divanadate as a powerful, selective oxidant of bromide, active at physiological pH, should make it a possible candidate of mimic in the action of vanadium in bromoperoxidase proteins.