Pollen morphology of the Swertiinae (Gentianaceae): phylogenetic implications

Recent molecular surveys of the Swertiinae (Gentianaceae–Gentianeae) revealed unexpected phylogenetic relationships, including polyphyly of the genera Gentianella , Jaeschkea , Lomatogonium and Swertia . To find new non-molecular characters supporting the phylogeny, we examined the exine variation of 73 species of all major lineages of subtribe Swertiinae using environmental scanning electron miscroscopy supplementing older, mainly light microscopical, studies. In contrast to previous studies, we were able to pick out taxa from phylogenetic key positions with particular focus on Swertia . Many distantly related taxa such as parts of Frasera , Gentianopsis , Halenia , Gentianella , Megacodon and several lineages of Swertia share a striate–reticulate or reticulate exine pattern. This is interpreted as the plesiomorphic character state of Swertiinae. There is also considerable variation of derived patterns; for example, different types of microechinate or almost smooth pollen was repeatedly observed in distantly related groups. Another extreme was the ring-shaped reticulation found in a North American species of Gentianopsis . Unfortunately, major relationships as revealed by molecular analyses were rarely supported because of the abundance of the plesiomorphic type and homoplasy even on low taxonomic levels; for example, within Lomatogonium . Exine variation was particularly useful in characterizing independent lineages of Swertia . For example, according to pollen characters and in agreement with other data, the Asian Swertia cuneata is a sister group of a strongly diversified African lineage and Swertia yunnanensis , which is rather aberrant in flower morphology, seems close to parts of Lomatogonium .  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 323–341.     

Standard hemispheres as indicators of flow characteristics in lotic benthos research

SUMMARY. 1. Standard hemispheres of identical size and surface but different densities were exposed on a horizontal plane at the bottom of streams. The heaviest hemisphere moved was used as an indicator of flow conditions close to the substrate.
2. Techniques of manufacture, maintenance, and use of the equipment were considered in detail.
3. The method was an easily applicable and integrated indicator of key hydraulic characteristics (turbulence or force of flow prevailing at the stream bottom) previously measured in lotic benthos research, and can replace these more laborious techniques.
4. The hemispheres enabled a rapid flow characterization in stream reaches, in smaller areas where the benthos was being quantitatively sampled, and in en/exclosure cages used in experimental studies.
5. The method also has the potential to characterize and compare physics of flow in individual running water segments with regard to frequencies and intensities of disturbances caused by long-term variations in discharge.
6. The hemispheres could be used as a standard in benthic research. since they offer a well defined scale that is directly comparable not only between studies in running waters but also in wave-exposed shores of lakes and oceans.     

High species diversity in one of the dominant groups of spiders in East African montane forests (Araneae: Pholcidae: Buitinga n. gen., Spermophora Hentz)

The six-eyed pholcid spiders of East Africa are revised. A new genus is recognized, Buitinga n. gen ., with 17 new species and three species transferred from Spermophora Hentz. The new genus is characterized by the presence of a scape on the epigynum. This scape may be straight or tightly curled up at rest, and is usually highly expandable. Seven additional African and Comoran species are newly described and tentatively assigned to Spermophora . A data matrix with 60 characters and 77 taxa (including 20 East African species and 25 additional Spermophora and ' Spermophora -like' species) is analysed cladistically. Buitinga is closer to the genera Paramicromerys Millot (endemic in Madagascar) and Spermophorides Wunderlich (Mediterranean and Canary Islands) as well as to several African and Comoran species tentatively assigned to Spermophora than to the type species of Spermophora . It is argued that current estimates of species numbers may be inaccurate and that pholcids may turn out to be one of the most diverse spider families.  © 2003 The Linnean Society of London. Zoological Journal of the Linnean Society, 2003, 137, 555−619     

POLYAMINE REGULATORY PROCESSES AND OXIDATIVE STRESS IN MONOCROTALINE-TREATED PULMONARY ARTERY ENDOTHELIAL CELLS

Alterations in polyamine metabolism may be a critical mechanism of monocrotaline (MCT)-induced structural remodeling of the pulmonary vasculature. In the present study, the hypothesis that MCT, through the induction of oxidative stress, modulates cellular polyamine regulatory mechanisms which in turn might be involved in the upregulation of fibronectin production in pulmonary artery endothelial cells (PAEC) was examined. A 24-h treatment with MCT significantly increased PAEC polyamine concentrations as compared to vehicle-treated cells. In addition, exposure to MCT caused an increase in abundance of ornithine decarboxylase (ODC) mRNA, upregulation of ODC activity and enhancement of spermidine import into PAEC. Inhibition ofde novopolyamine synthesis further increased spermidine uptake in MCT-treated cells. The depletion of cellular polyamine contents through the blockade of bothde novopolyamine biosynthesis and polyamine transport prevented MCT-induced increases in the medium level of fibronectin. In addition, PAEC treatment with MCT stimulated cellular oxidative stress as determined by increased levels of thiobarbituric acid reactive substances, enhanced dichlorofluorescein fluorescence and activation of NF-KB. A co-treatment with dimethylthiourea, an oxygen radical scavenger, prevented MCT-induced increases in cellular oxidation and attenuated disturbances in polyamine metabolism. These data suggest that MCT can stimulate polyamine regulatory processes in PAEC possibly through an increase in cellular oxidative stress. The present study may have significant implication in understanding mechanisms of MCT-induced pulmonary hypertension and remodeling of pulmonary vasculature.     

Phylogenetic analysis of Zygaenoidea small-subunit rRNA structural variation implies initial oligophagy on cyanogenic host plants in larvae of the moth genus Zygaena (Insecta: Lepidoptera)

Cyanogenesis, the release of toxic cyanide from living cells, plays an important role in the defence system of certain plant (e.g. Fabaceae) and animal (e.g. Zygaenidae) taxa. The larvae of a significant number of Zygaena moth species (Zygaenidae) preferentially feed on cyanogenic Fabaceae and some of them are able to sequester cyanogenic compounds of their host plants. Using secondary structure variation of the small-subunit rRNA, we tested the currently accepted evolutionary hypothesis explaining species diversification in the genus Zygaena . We derived secondary structures considering evidence from covariation patterns and thermodynamic folding and applied structural information in a phylogenetic analysis. Contrary to previous assumptions, our results suggest that the use of cyanogenic larval host plants is an ancient trait and that the ability to feed on cyanogenic plants was probably already present in the most recent common ancestor of Zygaena . The utilization of acyanogenic plants in Zygaena species appears to be the result of a single secondary, reverse, larval host-plant shift. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 147 , 367–381.     

Blue Light Induction of Barley Leaf Unfolding. A Phytochrome Reaction?

Low-energy blue light (450, 475 nm) has been found to induced unfolding of etiolated barley leaves (Hordeum rulgare cv. Ingrid). This induction can be reversed by far-red light. Barley leaf unfolding is normally stimulated by red light, reversed by far-red light, and can be considered to be a typical phytochrome controlled response. It is possible to explain the effects by red and blue light as mediated by the same photoreceptor. The phototransformation of this pigment results in two forms, P₂ and P₄, to which physiological activity can be ascribed. The red and blue light affect different steps in a cyclical photoconversion. Calculated theoretical dose response curves are presented for such a model in agreement with the experimental data.     

Southern African pholcid spiders: revision and cladistic analysis of Quamtana gen. nov. and Spermophora Hentz (Araneae: Pholcidae), with notes on male−female covariation

The southern African pholcid spiders previously assigned to Pholcus and Spermophora are revised and their phylogenetic position within Pholcidae is analysed cladistically. Two distinct groups are recognized: the first is restricted to the Cape region and probably correctly placed in Spermophora ; it includes Spermophora peninsulae Lawrence and four new species. The second is more widely distributed in southern and eastern South Africa, and reaches as far north as Cameroon, Congo (Democratic Republic) and Uganda; it is assigned generic status ( Quamtana gen. nov .), and includes two species transferred from Pholcus [ Q. leptopholcica (Strand), Q. ciliata (Lawrence)] as well as 23 new species. A key to the pholcid spiders of South Africa is presented. A close correlation between a male character (distance between cheliceral apophyses) and a female character (distance between pockets on epigynum) is documented in Quamtana .  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society, 2003, 139 , 477−527.