The identity of <Emphasis Type="Italic">Zamia katzeriana</Emphasis> and <Emphasis Type="Italic">Z. verschaffeltii</Emphasis> (Zamiaceae)

The morphological variation of recently described species (also the older taxa) of Zamia distributed within southeastern Mexico that have wide, coriaceous leaflets is analyzed. The complex is designated as the Z. katzeriana species complex in reference to an historic collection of this name, which is also the earliest named species in the complex. The complex consists of Z. cremnophila, Z. lacandona, Z. splendens and Z. purpurea. During the 1990’s, Z. splendens was separately synonymized under Z. katzeriana and Z. verschaffeltii, both collected in Mexico by German collectors during the 18th century, but the precise locality is unknown. Information concerning the incomplete holotype of Z. verschaffeltii is particularly ambiguous, and the possible type locality suggested by Schuster, Socorro, is imprecise, thus generating taxonomic confusion. Morphometric characterization and discriminant analysis of the contemporary and historic collections (i.e., Z. katzeriana and Z. verschaffeltii) included all the known populations (11) and individuals (115) of the complex throughout its range. The results show that Z. verschaffeltii is not morphometrically related to any of the species in the complex and that Z. splendens should be considered a synonym of Z. katzeriana.

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Resumen  En este artículo se caracteriza la variación morfológica de las especies de un complejo de Zamia, que presentan folíolos anchos y coriáceos con distribución en el sureste de México, la mayoría de reciente descripción. El complejo es denominado Z. katzeriana, por una colección histórica de este nombre, y consiste de Z. cremnophila, Z. lacandona, Z. splendens y Z. purpurea. Zamia splendens fue sinonimizada separadamente bajo dos colecciones históricas Z. katzeriana y Z. verschaffeltii, de las cuales se desconoce con exactitud su lugar de procedencia, excepto que fueron colectadas en México por botánicos alemanes del siglo XVIII. La información, en especial sobre el holotipo incompleto de Z. verschaffeltii es muy ambigua y la posible localidad tipo mencionada por Schuster, Socorro, es imprecisa, lo cual ha generado confusiones taxonómicas. La caracterización de la variación morfométrica incluyó a todas las poblaciones (11) e individuos (115) conocidas actualmente para el complejo en todo su rango de distribución en México. El análisis discriminante incluyendo a las colecciones históricas, determina que Z. verschaffeltii no está relacionado morfométricamente con ninguna especie del complejo y Z. katzeriana está estrechamente correlacionada con Z. splendens.

     

Identification of Metal Oxide Nanoparticles in Histological Samples by Enhanced Darkfield Microscopy and Hyperspectral Mapping

Nanomaterials are increasingly prevalent throughout industry, manufacturing, and biomedical research. The need for tools and techniques that aid in the identification, localization, and characterization of nanoscale materials in biological samples is on the rise. Currently available methods, such as electron microscopy, tend to be resource-intensive, making their use prohibitive for much of the research community. Enhanced darkfield microscopy complemented with a hyperspectral imaging system may provide a solution to this bottleneck by enabling rapid and less expensive characterization of nanoparticles in histological samples. This method allows for high-contrast nanoscale imaging as well as nanomaterial identification. For this technique, histological tissue samples are prepared as they would be for light-based microscopy. First, positive control samples are analyzed to generate the reference spectra that will enable the detection of a material of interest in the sample. Negative controls without the material of interest are also analyzed in order to improve specificity (reduce false positives). Samples can then be imaged and analyzed using methods and software for hyperspectral microscopy or matched against these reference spectra in order to provide maps of the location of materials of interest in a sample. The technique is particularly well-suited for materials with highly unique reflectance spectra, such as noble metals, but is also applicable to other materials, such as semi-metallic oxides. This technique provides information that is difficult to acquire from histological samples without the use of electron microscopy techniques, which may provide higher sensitivity and resolution, but are vastly more resource-intensive and time-consuming than light microscopy.     

Phylogenetic analyses of nucleotide sequences confirm a unique plant intercontinental disjunction between tropical Africa, the Caribbean, and the Hawaiian Islands

Phylogenetic analyses of nucleotide sequences of the internal transcribed spacers and 5.8 regions of the nuclear ribosomal DNA and of the trnH-psbA spacer of the chloroplast genome confirm that the three taxa of the Jacquemontia ovalifolia (Choicy) Hallier f. complex (Convolvulaceae) form a monophyletic group. Levels of nucleotide divergence and morphological differentiation among these taxa support the view that each should be recognized as distinct species. These three species display unique intercontinental disjunction, with one species endemic to Hawaii (Jacquemontia sandwicensis A. Gray.), another restricted to eastern Mexico and the Antilles [Jacquemontia obcordata (Millspaugh) House], and the third confined to East and West Africa (J. ovalifolia). The Caribbean and Hawaiian species are sister taxa and are another example of a biogeographical link between the Caribbean Basin and Polynesia. We provide a brief conservation review of the three taxa based on our collective field work and investigations; it is apparent that J. obcordata is highly threatened and declining in the Caribbean.     

17β-oestradiol acts as a negative modulator of insulin-induced lactotroph cell proliferation through oestrogen receptor α, via nitric oxide/guanylyl cyclase/cGMP

Objectives: 17β‐oestradiol interacts with growth factors to modulate lactotroph cell population. However, contribution of isoforms of the oestrogen receptor in these activities is not fully understood. In the present study, we have established participation of α and β oestrogen receptors in effects of 17β‐oestradiol on lactotroph proliferation induced by insulin and shown involvement of the NO/sGC/cGMP pathway. Materials and methods: Cell cultures were prepared from anterior pituitaries of female rats to evaluate lactotroph cell proliferation using bromodeoxyuridine (BrdUrd) detection, protein expression by western blotting and cGMP by enzyme immunoassay. Results: In serum‐free conditions, 17β‐oestradiol and α and β oestrogen receptor agonists (PPT and DPN) failed to increase numbers of lactotroph cells undergoing mitosis. Co‐incubation of 17β‐oestradiol/insulin and PPT/insulin significantly decreased lactotroph mitogenic activity promoted by insulin alone. Both ICI 182780 and NOS inhibitors (L‐NMMA and L‐NAME) induced reversal of the anti‐proliferative effect promoted by 17β‐oestradiol/insulin and PPT/insulin. Moreover, 17β‐oestradiol, PPT and insulin increased sGC α1 protein expression and inhibited β1, whereas co‐incubation of 17β‐oestradiol/insulin or PPT/insulin induced increases of the two isoforms α1 and β1. 17β‐oestradiol and insulin reduced cGMP production, while 17β‐oestradiol/insulin co‐incubation increased this cyclic nucleotide. Conclusions: Our results suggest that 17β‐oestradiol is capable of arresting lactotroph proliferation induced by insulin through ER α with participation of the signalling NO/sGC/cGMP pathway.     

Drosophila katanin is a microtubule depolymerase that regulates cortical-microtubule plus-end interactions and cell migration

Regulation of microtubule dynamics at the cell cortex is important for cell motility, morphogenesis and division. Here we show that the Drosophila katanin Dm-Kat60 functions to generate a dynamic cortical-microtubule interface in interphase cells. Dm-Kat60 concentrates at the cell cortex of S2 Drosophila cells during interphase, where it suppresses the polymerization of microtubule plus-ends, thereby preventing the formation of aberrantly dense cortical arrays. Dm-Kat60 also localizes at the leading edge of migratory D17 Drosophila cells and negatively regulates multiple parameters of their motility. Finally, in vitro, Dm-Kat60 severs and depolymerizes microtubules from their ends. On the basis of these data, we propose that Dm-Kat60 removes tubulin from microtubule lattice or microtubule ends that contact specific cortical sites to prevent stable and/or lateral attachments. The asymmetric distribution of such an activity could help generate regional variations in microtubule behaviours involved in cell migration.     

Antifeedant/insecticidal terpenes from asteraceae and labiatae species native to Argentinean semi-arid lands

To validate the potential as added-value resources of Asteraceae and Labiatae species of Argentinean semi-arid lands, we have selected 13 of their major terpenoids belonging to several chemical classes and tested their insect antifeedant and toxic activity on the herbivorous insects Spodoptera littoralis and Leptinotarsa decemlineata. The antifeedant effects of the test compounds were structure- and species-dependent. The most active antifeedant to L. decemlineata was the eudesmane sesquiterpene gamma-costic acid (13), followed by the labdane diterpene 2alpha,3alpha-dihydroxycativic acid (8), the clerodane diterpenes 6-acetylteucjaponin B (5), bacchotricuneatin A (1), bartemidiolide (7), butanolide (4), and the sesquiterpenes ilicic acid (11) and tessaric acid (10) (eudesmane and eremophilane type, respectively). S. littoralis was only affected by the clerodanes and showed the strongest response to salviarin (3) and 5, followed by hawtriwaic acid (6) and 12-epi-bacchotricuneatin A (2). Orally injected S. littoralis larvae were negatively affected by 5. Most of the diterpenes had selective cytotoxic effects to insect-derived Sf9 cells with the clerodane 1 being the most active, followed by the eudesmane costic acid (12), the only cytotoxic sesquiterpene. None of these compounds was cytotoxic to mammalian CHO cells.     

A molecular phylogenetic study of Graptopetalum (Crassulaceae) based on ETS, ITS, RPL16, and TRNL-F nucleotide sequences

Nuclear ETS and ITS, as well as plastid rpl16 and trnL-F DNA sequences were used to determine relationships among species of Graptopetalum (Crassulaceae) and closely related genera. Graptopetalum is member of a group of taxa restricted to North America, one of the centers of diversity of Crassulaceae; however, their phylogenetic relationships are not yet understood. Nineteen species of Graptopetalum and 24 species from nine other genera of Crassulaceae were sampled for use in three separate parsimony analyses: ITS alone, ETS alone, and a combined nuclear + plastid DNA analysis using all four gene regions. The ETS data set had the highest number of parsimony-informative sites, about 30% more than in ITS, but the most fully resolved tree resulted when the four DNA regions were combined. Only four subclades of the tree received moderate to strong bootstrap support, one of which includes all species of Graptopetalum having a single whorl of stamens. However, Graptopetalum is not monophyletic. Instead, Tacitus bellus and select species of Cremnophila, Sedum, and Echeveria are interspersed among species of Graptopetalum and show evidence of grouping according to geographical range of distribution more so than habit or floral morphology.     

A new improved strategy for the selection of cold-adapted antagonist yeasts to control postharvest pear diseases

Postharvest diseases cause considerable losses of harvested fruits during transportation and storage. Many yeast species have been reported as good antagonists against postharvest pear pathogens. In this work, we used a novel selection strategy that involves the isolation of yeasts from washing fluids, showing biocontrol activity against a regional Penicillium expansum strain (primary screening), originally obtained from fruit wounds after long time storage at ?1/0°C. About 26 isolates representative of the 11 yeast species identified in the 27 selected washing waters were chosen to be evaluated in a secondary screening against a regional Botrytis cinerea strain on pear wounds. Among yeasts tested, 38% showed complete control of P. expansum, but only 15% reduced the decay incidence of B. cinerea to 60–80% at ?1/0°C. These results reveal that some of the yeasts found can be biological alternatives to fungicides in the control of P. expansum and B. cinerea infections. Based on the data obtained, our strategy seems to be much more effective than the previously reported methods in obtaining successful biocontrol agents.     

Biosafety evaluation of recombinant protein production in goat mammary gland using adenoviral vectors: preliminary study

The production of recombinant proteins in the milk of non-transgenic goats can be achieved by transducing the mammary gland with recombinant adenoviral vectors. However, this process involves several regulatory issues. The current study evaluates the biosafety of this production system. We present a preliminary biosafety profile based on detection of adenoviral particles in different body fluids and the antibody response after adenoviral transduction of the goat mammary gland. In addition, two methods of adenoviral inactivation in milk were tested. Although adenoviral particles were detected in the milk until day 4 after transduction, they were absent in serum, saliva, urine and feces. Anti-adenovirus antibodies were detected in serum and milk. The virus inactivation methods neutralized adenoviral particles and preserved the immunological identity of the recombinant protein. These results support the idea of a safe production of recombinant proteins using adenoviral vectors.