Molecular phylogeny of Solms‐laubachia (Brassicaceae) s.l., based on multiple nuclear and plastid DNA sequences,and its biogeographic implications

Abstract The Hengduan Mountains region of south‐west China is a noted biodiversity hotspot, but the geographic origins and historical assembly of its rich endemic flora, including the sky‐island species of Solms‐laubachia Muschl. (Brassicaceae), have been little studied. Previous molecular studies on the phylogeny of Solms‐laubachia showed it to be paraphyletic, leading to considerable expansion not only of its taxonomic limits, but also its geographic range, with the inclusion of taxa from outside the Hengduan region. However, these studies provided little resolution of interspecific relationships, preventing inferences about historical biogeography within the clade. In the present study, new sequence data from two nuclear genes (LEAFY and G3pdh) and two chloroplast intergenic spacers (petN–psbM and psbM–trnD) were combined with existing markers to increase phylogenetic signals. Phaeonychium villosum (Maxim.) Al‐Shehbaz was found to be nested within Solms‐laubachia s.l. In general, phylogenetic relationships appear to be a good predictor of geography, with the Hengduan Mountain endemics embedded in a paraphyletic grade of species from the western Himalayas and central Asia, but they also imply morphological homoplasy. Incongruence was detected between the nuclear and chloroplast gene trees, perhaps resulting from incomplete lineage sorting of ancestral polymorphisms. The crown age of Solms‐laubachia s.l. was estimated to be approximately 1.42–3.68 mya, using Bayesian relaxed molecular clock analysis. Historical biogeographic analysis using a parametric dispersal–extinction–cladogenesis model inferred central Asia and the western Himalayas as most probable ancestral range of Solms‐laubachia s.l., and estimated higher rates of eastward expansion than westward during the diversification of descendant lineages. In summary, our results suggest that Solms‐laubachia s.l. originated during the Pliocene in central Asia, and subsequently migrated eastward into the Hengduan Mountains, colonizing sky‐island, alpine scree‐slope habitats that may have provided novel ecological opportunity and accelerated speciation, ultimately establishing this region as the present center of diversity of the genus.     

Impact of white‐tailed deer on the spread of Borrelia burgdorferi

There is a public perception that the white‐tailed deer Odocoileus virginianus (Artiodactyla: Cervidae) is the main reservoir supporting the maintenance and spread of the causative agent of Lyme disease, Borrelia burgdorferi. This study examines the pathogen prevalence rate of Borrelia in adult Ixodes scapularis (Ixodida: Ixodidae), the black‐legged tick, collected from white‐tailed deer and compares it with pathogen prevalence rates in adult ticks gathered by dragging vegetation in two contiguous counties west of the Hudson Valley in upstate New York. In both Broome and Chenango Counties, attached and unattached ticks harvested from white‐tailed deer had significantly lower prevalences of B. burgdorferi than those collected from vegetation. No attached ticks on deer (n = 148) in either county, and only 2.4 and 7.3% of unattached ticks (n = 389) in Broome and Chenango Counties, respectively, were harbouring the pathogen. This contrasts with the finding that 40.8% of ticks in Broome County and 46.8% of ticks in Chenango County collected from vegetation harboured the pathogen. These data suggest that a mechanism in white‐tailed deer may aid in clearing the pathogen from attached deer ticks, although white‐tailed deer do contribute to the spatial distribution of deer tick populations and also serve as deadend host breeding sites for ticks.     

HPLC‐Fluorescence Method for the Enantioselective Analysis of Propranolol in Rat Serum Using Immobilized Polysaccharide‐Based Chiral Stationary Phase

A stereoselective high‐performance liquid chromatographic (HPLC) method was developed and validated to determine S‐(?)‐ and R‐(+)‐propranolol in rat serum. Enantiomeric resolution was achieved on cellulose tris(3,5‐dimethylphenylcarbamate) immobilized onto spherical porous silica chiral stationary phase (CSP) known as Chiralpak IB. A simple analytical method was validated using a mobile phase consisted of n‐hexane‐ethanol‐triethylamine (95:5:0.4%, v/v/v) at a flow rate of 0.6 mL min^‐1 and fluorescence detection set at excitation/emission wavelengths 290/375 nm. The calibration curves were linear over the range of 10–400 ng mL^‐1 (R = 0.999) for each enantiomer with a detection limit of 3 ng mL^‐1. The proposed method was validated in compliance with ICH guidelines in terms of linearity, accuracy, precision, limits of detection and quantitation, and other aspects of analytical validation. Actual quantification could be made for propranolol isomers in serum obtained from rats that had been intraperitoneally (i.p.) administered a single dose of the drug. The proposed method established in this study is simple and sensitive enough to be adopted in the fields of clinical and forensic toxicology. Molecular modeling studies including energy minimization and docking studies were first performed to illustrate the mechanism by which the active enantiomer binds to the β‐adrenergic receptor and second to find a suitable interpretation of how both enantiomers are interacting with cellulose tris(3,5‐dimethylphenylcarbamate) CSP during the process of resolution. The latter interaction was demonstrated by calculating the binding affinities and interaction distances between propranolol enantiomers and chiral selector. Chirality 26:194–199, 2014. © 2014 Wiley Periodicals, Inc.     

Phylogeny of Six Genera of the Subclass Haptoria (Ciliophora,Litostomatea) Inferred from Sequences of the Gene Coding for Small Subunit Ribosomal RNA

ABSTRACT. The small subunit ribosomal RNA genes of nine species belonging to six genera of litostome ciliates, namely Amphileptus aeschtae, Chaenea teres, Chaenea vorax, Lacrymaria marina, Litonotus paracygnus, Loxophyllum sp.‐GD‐070419, Loxophyllum jini, Loxophyllum rostratum, and Phialina salinarum, were sequenced for the first time. Phylogenetic trees were constructed using different methods to assess the inter‐ and intra‐generic relationships of haptorians, of which Chaenea, Lacrymaria, Litonotus, and Phialina were analyzed for the first time based on molecular data. Monophyly of the order Pleurostomatida was strongly confirmed, and the two existing families of pleurostomatids, created on the basis of morphology, were confirmed by molecular evidence. Within the Pleurostomatida, Siroloxophyllum utriculariae occupied a well‐supported position basal to the Loxophyllum clade, supporting the separation of these genera from one another. Both the subclass Haptoria and the order Haptorida were partially unresolved, possibly paraphyletic assemblages of taxa in all analyses, creating doubts about the traditional placement of some haptorid taxa. The existing sequence of L. rostratum in GenBank (DQ411864) was conspicuously different from that of the isolate from Qingdao, China sequenced in the present work, indicating that they are different species. The isolate from Qingdao was verified as L. rostratum by morphological analysis, and the published morphology of existing GenBank record of L. rostratum is different from it. Based on both morphological and molecular evidence, the latter may be congeneric with an undescribed species of Loxophyllum from Guangdong Province, China.     

Re‐targeting of a plant defense protease by a cyst nematode effector

Plants mount defense responses during pathogen attacks, and robust host defense suppression by pathogen effector proteins is essential for infection success. 4E02 is an effector of the sugar beet cyst nematode Heterodera schachtii. Arabidopsis thaliana lines expressing the effector‐coding sequence showed altered expression levels of defense response genes, as well as higher susceptibility to both the biotroph H. schachtii and the necrotroph Botrytis cinerea, indicating a potential suppression of defenses by 4E02. Yeast two‐hybrid analyses showed that 4E02 targets A. thaliana vacuolar papain‐like cysteine protease (PLCP) ‘Responsive to Dehydration 21A’ (RD21A), which has been shown to function in the plant defense response. Activity‐based protein profiling analyses documented that the in planta presence of 4E02 does not impede enzymatic activity of RD21A. Instead, 4E02 mediates a re‐localization of this protease from the vacuole to the nucleus and cytoplasm, which is likely to prevent the protease from performing its defense function and at the same time, brings it in contact with novel substrates. Yeast two‐hybrid analyses showed that RD21A interacts with multiple host proteins including enzymes involved in defense responses as well as carbohydrate metabolism. In support of a role in carbohydrate metabolism of RD21A after its effector‐mediated re‐localization, we observed cell wall compositional changes in 4E02 expressing A. thaliana lines. Collectively, our study shows that 4E02 removes RD21A from its defense‐inducing pathway and repurposes this enzyme by targeting the active protease to different cell compartments.     

The Detection of Inhibitors of the Sclerotinia sclerotiorum (Lib.) de Bary Extracellular Proteinases in Sunflower

Abstract: Water-soluble protein fractions from leaves, seeds and heads of sunflower were shown to contain inhibitors of trypsin, chymotrypsin and extracellular proteinases from Sclerotinia sclerotiorum , a pathogen of sunflower, and Colletotrichum lindemuthianum. These included bifunctional inhibitors of trypsin and subtilisin. Comparison with the patterns of inhibition of standard proteinases indicated that the major extracellular proteinases of S. sclerotiorum are subtilisin-like. It is speculated that the sunflower inhibitors play a role in conferring resistance to fungal infection.     

The effect of nutrient availability and temperature on chain length of the diatom, Skeletonema costatum

We determined the effects of temperature and nutrients on thechain length of a diatom, Skeletonema costatum, in batch cultureand enclosure experiments with estuarine water from San FranciscoBay, USA, using the recently developed CytoBuoy flow cytometer.Determination of the number of cells per diatom chain by CytoBuoyflow cytometer and associated software correlated well withbut was much more precise and time efficient than microscopicquantification. Increasing temperatures (from 6, 8 to 17°C)and nutrient concentrations induced high growth rates and dominanceby longer chains in a cultured S. costatum strain that was originallyacclimatized to a temperature range of 11–30°C. Similarly,a positive correlation between growth rate and chain lengthwas observed in S. costatum in batch culture and natural communitiesin enclosure experiments. Maximal chain lengths of S. costatumwere greater in natural populations than in the batch culture.Longer chains affect sinking rates and thus likely help thediatom remain suspended in the upper part of the water columnwhere physical and chemical parameters are more favorable forgrowth.     

促胰液素和胆囊收缩素族激素对豚鼠肝胆汁分泌的影响

用具备胃瘘和胆瘘的豚鼠于人工维持胆汁酸池恒定的条件下,观察促胰液素(SEC)和胆囊收缩素(CCK)族激素[包括雨蛙肽(CAE)、五肽胃泌素(G5)和内源性CCK]对肝胆汁分泌的影响及其相互作用。结果表明:静脉灌注SEC、CAE或肠内灌注左旋苯丙氨酸(L-PHE,促内源性CCK释放剂)后,胆汁流量、胆汁HCO~-_3和Cl~-排出量均显著增多,并呈剂量-效应关系,但静脉注射G5则无利胆效应。在恒速灌注SEC的背景下,CAE或CCK对胆汁HCO~-_3排出的效应分别大于它们单独给予时的效应(P<0.05或P<0.01)。这些激素对胆汁酸的排出量均无影响。上述结果表明,SEC,CAE和内源性CCK均有利胆作用,所刺激的肝胆汁属于不依赖胆汁酸部分。G5则无利胆效应。对胆汁中HCO~-_3的排出,SEC与CAE或内源性CCK间有相互加强作用。