The intersectional hybrid between Weigela hortensis and W. maximowiczii (Caprifoliaceae)

Morphologically intermediate plants between Weigela hortensis (Siebold & Zucc.) K.Koch and W. maximowiczii (S.Moore) Rehder have been found in Miyagi and Yamagata Pref., northern Japan. Quantitative character analyses of flowers, pollen stainability and molecular analyses indicated that the intermediate plants were hybrids of those two species. This is the first record of an intersectional hybrid with W. maximowiczii (sect. Weigelastrum ) as one of the parent species. The morphological differences among hybrid individuals imply the possibility of backcrosses or formation of second or later generations of hybrids, although those may be quite rare because of a low frequency of viable pollen grains. Causes of hybridization between two distantly-related species in Weigela are discussed. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 369–380.     

Nearest Neighbor Classification Rule for Mixtures of Discrete and Continuous Random Variables

In this paper very simple nonparametric classification rule for mixtures of discrete and continuous random variables is described. It is based on the method of nearest neighbor proposed by Cover and Hart (1967). The bounds on the limit of the nearest neighbor rule risks are given. Both lower and upper bound depend on the Bayes risk and the loss function. Finally the method is compared with other existing methods on some practical data set.     

Chromatographic separation of extruded iron-sulfur cores from the apoproteins of Clostridium pasteurianum and spinach ferredoxins in aqueous Triton X-100/urea

Iron-sulfur core extrusions from spinach [( 2Fe-2S]) and Clostridium pasteurianum (2[4Fe-4S]) ferredoxins in aqueous Triton X-100/urea containing excess benzenethiol yield quantitatively [FenSn(SPh)4]2- with n = 2 and n = 4, respectively. The iron-sulfur cluster can be separated from the corresponding apoprotein by rapid passage of the extrusion mixture over a small anaerobic column of Whatman DE-52 anion-exchange cellulose. Essentially quantitative recovery of [FenSn (SPh)4]2- is achieved in the eluate. The apoprotein remaining on the column can be eluted with 0.5 M NaCl. Most of the residual Triton X-100 and benzenethiol can be removed by passage of the apoprotein eluate over a small column of Bio-Beads SM-2, a hydrophobic polystyrene adsorbent. Apoprotein recovery is comparable to that obtained by other chromatographic methods. At least with spinach ferredoxin, the apoprotein prepared in this fashion can be reconstituted. The procedures developed in this work are potentially most applicable to selective removal of [2Fe-2S] and [4Fe-4S] centers from a multicenter enzyme without irreversible denaturation.     

Amino acid analysis of bone from a possible case of prehistoric iron deficiency anemia from the American southwest

It is possible that dietary conditions can result in the production of abnormal bone protein. For example, a heavily maize-dependent diet could be deficient in one or more essential amino acids necessary to normal human biochemistry and consequently necessary for normal bone protein synthesis. Amino acid analysis of bone tissues, thus, could provide a useful diagnostic tool in paleopathology. To test this potential we have compared the amino acid analyses of bone samples from a prehistoric Southwest Indian child exhibiting porotic hyperostosis with samples taken from (1) two children's skeletons lacking bone lesions but from the same area and time, (2) a modern child who died from accidental causes, and (3) adult human compact bone. Analytical results of the nonpathological prehistoric specimens were virtually identical to that of the modern infant, indicating remarkable preservation of bone protein. The pathological bone sample differed from the three control specimens by having as much as 25% less of those amino acids containing hydroxyl group and acidic side chains. We interpret the amino acid profile for the diseased child as indicating the presence of a greater proportion of helical protein (or less noncollagenous protein) as well as a lowered degree of hydroxylation of proline and lysine. One explanation for our data is that protein biosynthesis is altered in the child exhibiting porotic hyperostosis, and either some proteins important in the early phases of mineralization are not produced in sufficient quantity, or some necessary enzyme cofactors (e.g., dietary ferrous ions) are missing. We conclude that our data are compatible with, but do not prove, the hypothesis that the porotic hyperostosis exhibited by the Southwest Indian child is the result of iron deficiency anemia.     

An order-specific monoclonal antibody to Diptera reveals the impact of alternative prey on spider feeding behavior in a complex food web

Generalist predators have the capacity to restrict pest population growth, especially early in the season before densities increase. However, their polyphagous feeding habits sometimes translate into reduced pest consumption when they target alternative prey. An order-specific monoclonal antibody was developed to examine the strength of trophic connections between Diptera, a major category of non-pest prey, and linyphiid spiders in alfalfa. We report the development and characterization of a monoclonal antibody with order-level specificity to Diptera. This antibody elicited strong absorbance to 22 Diptera from 13 families, no false-positive reactivity to non-dipteran invertebrates, and antigen detection periods following prey consumption that were comparable between spiders. Over 900 field-collected females of the linyphiid spiders Erigone autumnalis and Bathyphantes pallidus were screened for Diptera antigen. Significantly more B. pallidus screened positive for Diptera (40%) compared to E. autumnalis (16%), indicating differential reliance on these prey. In parallel with the collection of spiders for gut-content analysis, prey availability was estimated at web sites. The two spiders exhibited different feeding responses to prey availability. Consumption of Diptera by B. pallidus was strongly correlated with Diptera abundance whilst the availability of other potential prey did not influence predation rates. Conversely, E. autumnalis did not prey upon Diptera in proportion to availability, but increased Collembola activity-density reduced dipteran consumption. Integration of molecular gut-content analysis with precise sampling of prey demonstrated how two closely related linyphiid spiders exhibit different feeding responses to the availability of prey under natural field conditions. Elucidating the feeding preferences of natural enemies is critical to effective incorporation of biological control by generalist predators in the management of agricultural pests.     

K+(Rb+) and Ca2+ fluxes in young winter wheat plants exposed to sub-zero temperatures

Ice crystal formation temperature was determined in the region of the crown in one group of 7-day-old intact unhardened high-salt plants of winter wheat (Triticum aestivum L. cv. Weibulls Starke II) with TA (Thermal Analysis) and DTA (Differential Thermal Analysis) methods. After exposure of another group of plants, grown for the first 7 days in the same way as the first group, to various sub-zero temperatures (-1 to 5°C), influx in roots of Rb⁺(⁸⁶Rb⁺) and Ca²⁺(⁴⁵Ca²⁺) and contents of K⁺ and Ca²⁺ were determined at intervals during 7 days of recovery. Ice crystal formation in the crown tissue was probably extracellular and took place at about -4°C. There was a large loss of K⁺ from the roots after treatment at sub-zero temperatures. This loss increased as the temperature of the sub-zero treatment decreased. During recovery, roots of plants exposed to -1, -2 and -3°C gradually reabsorbed K⁺. Reabsorption of K⁺ in roots of plants exposed to -4°C was greatly impaired. Rb⁺ influx decreased and Ca²⁺ influx increased after sub-zero temperature treatments of the plants. Active Rb⁺ influx mechanisms and active extrusion of Ca²⁺ were impaired or irreversibly damaged by the exposure. While Rb⁺ influx mechanisms were apparently repaired during recovery in plants exposed to temperatures down to -3°C, Ca²⁺ extrusion mechanisms were not. The temperature for ice crystal formation in the region of the crown tissue coincides with the temperature at which the plants lost the ability to reabsorb K⁺ and to repair Rb⁺ influx mechanisms during the recovery period. Plants were lethally damaged at temperatures below ?4°C.     

Flood Risk Analysis Based on Information Diffusion Theory

Due to the fact that the flood data series of small drainage basins is relatively short, available data are often not sufficient for flood risk analysis. This presents the problem of risk analysis using very small data samples. One method that can be applied is to regard the available small samples as fuzzy information and optimize them using information diffusion technology to yield analytical results with greater reliability. In this article a risk analysis method based on information diffusion theory is applied to create a new flood risk analysis model. Application of the model is illustrated taking the Jinhuajiang and Qujiang drainage basins as examples. This is a new attempt at applying information diffusion theory in flood risk analysis. Computations based on this analytical flood risk model can yield an estimated flood damage value that is relatively accurate. This study indicates that the aforementioned model exhibits fairly stable analytical results, even when using a small set of sample data. The results also indicate that information diffusion technology is highly capable of extracting useful information and therefore improves system recognition accuracy. This method can be easily applied and the analytical results produced are easy to understand. Results are accurate enough to act as a guide in disaster situations.     

Two oligosaccharides from Marsdenia roylei

Phytochemical analysis of dried twigs of Marsdenia roylei (family Asclepiadaceae) has resulted in the isolation of a trisaccharide, maryal, and a diglycoside, rolinose. Their structures were determined as O-beta-D-oleandropyranosyl-(1-->4)-O-beta-D-digitoxopyranosyl++ +-(1-->4)-D- cymaral and ethyl O-beta-D-oleandropyranosyl-(1-->4)-O-3-O-methyl-6-deoxy-beta-D- allopyranoside, respectively, by chemical degradation and spectroscopic methods.     

UDP-N-acetylglucosamine 1-carboxyvinyl-transferase from Acinetobacter calcoaceticus

Abstract We have analyzed the sequence downstream of rpoN from Zcinetobacter calcoaceticus and identified an open reading frame encoding a protein with high similarity to UDP- N -acetylgucosamine 1-carboxyvinyl-transferase (MurZ). Multicopy plasmids encoding this enzyme conferred phosphomycin resistance to A. calcoaceticus . The polar effect of a rpoN mutation on the phosphomycin resistance level suggests that murZ is, in part, cotranscribed with rpoN . These observations confirm that A. calcoaceticus represents the first exceptin from a conserved genetic context of rpoN observed in several other Gram-negative bacteria.     

Dispersal vs. vicariance in the Mediterranean: historical biogeography of the Palearctic Pachydeminae (Coleoptera, Scarabaeoidea)

Aim The geological evolution of the Mediterranean region is largely the result of the Tertiary collision of the African and Eurasian Plates, but also a mosaic of migrating island arcs, fragmenting tectonic belts, and extending back‐arc basins. Such complex paleogeography has resulted in a ‘reticulate’ biogeographical history, in which Mediterranean biotas repeatedly fragmented and merged as dispersal barriers appeared and disappeared through time. In this study, dispersal‐vicariance analysis (DIVA) is used to assess the relative role played by dispersal and vicariance in shaping distribution patterns in the beetle subfamily Pachydeminae Reitter, 1902 (Scarabaeoidea), an example of east–west Mediterranean disjunction. Location The Mediterranean region, including North Africa, the western Mediterranean, Balkans–Anatolia, Middle East, Caucasus, the Iranian Plateau, and Central Asia. Methods A phylogenetic hypothesis of the Palearctic genera of Pachydeminae in conjunction with distributional data was analysed using DIVA. This method reconstructs the ancestral distribution in a given phylogeny based on the vicariance model, while allowing dispersal and extinction to occur. Unlike other methods, DIVA does not enforce area relationships to conform to a hierarchical ‘area cladogram’, so it can be used to reconstruct ‘reticulate’ biogeographical scenarios. Results Optimal reconstructions, requiring 23 dispersal events, suggest that the ancestor of Pachydeminae was originally present in the south‐east Mediterranean region. Basal splitting within the subfamily was caused by vicariance events related to the late Tertiary collision of the African microplates Apulia and Arabia with Eurasia, and the resultant arise of successive dispersal barriers (e.g. the Red Sea, the Zagros Mountains). Subsequent diversification in Pachydeminae involved multiple speciation events within the Middle East and Iran–Afghanistan regions, which gave rise to the least speciose genera of Pachydeminae (e.g. Otoclinius Brenske, 1896). Finally, the presence of Pachydeminae in the western Mediterranean region seems to be the result of a recent dispersal event. The ancestor of the Iberian genera Ceramida Baraud, 1987 and Elaphocera Gené, 1836 probably dispersed from the Middle East to the Iberian Peninsula across North Africa and the Gibraltar Strait during the ‘Messinian salinity crisis’ at the end of the Miocene. Main conclusions Although the basal diversification of Pachydeminae around the Mediterranean appears to be related to vicariance events linked to the geological formation of the Mediterranean Basin, dispersal has also played a very important role. Nearly 38% of the speciation events in the phylogeny resulted from dispersal to a new area followed by allopatric speciation between lineages. Relationships between western and eastern Mediterranean disjuncts are usually explained by dispersal through Central Europe. The biogeographical history of the Pachydeminae corroborates other biogeographical studies that consider North Africa to be an alternative dispersal route by which Mediterranean taxa could have achieved circum‐Mediterranean distributions.