The phylogeny of Patrinieae sensu Graebner (Valerianaceae) revisited: additional evidence from ndhF sequence data

 DNA sequences of both 5′ and 3′ regions of the plastid ndhF gene were generated in order to study the position of Patrinia and Nardostachys, to check the potential paraphyletic nature of Patrinieae, and to evaluate the possible link between the tribe and Linnaeaceae. Parsimony analysis showed very strong support for Patrinia as sister to all members of Valerianaceae (including Nardostachys) and indicated the paraphyletic nature of the tribe Patrinieae. Additionally, trees were constructed from available rbcL data separately and supplemented with ndhF sequences. Topologies of these combined cladograms are in agreement with the ndhF phylogeny, suggesting that the traditionally circumscribed Patrinieae can no longer be recognized but must be considered as part of a basal grade in Valerianaceae. Parsimony analysis based on a morphological data set supported a monophyletic Patrinieae; combination with the molecular data showed a paraphyletic Patrinieae. Furthermore, the possible link between Patrinieae and Linnaeaceae is evaluated. Received July 12, 2001 Accepted February 25, 2002     

A comparison between modern pollen spectra of moss cushions and Cundill pollen traps

Pollen spectra of 23 Cundill pollen traps from 23 different sampling sites in Southwest Turkey are compared with the corresponding pollen spectra of moss cushions from the same sites. The Cundill pollen traps represent the modern pollen rain data from one year whereas the moss cushions represent the pollen rain of several years. The comparative study reveals some main differences between the two pollen entrapment media. The one-year entrapment medium (pollen trap) appears to be more sensitive for local (releve area 10x10 m) and regional (100-500 m, or a few kilometres for Olea europaea) vegetation. Pollen spectra of moss cushions are dominated by high pine pollen percentage values and hardly sense fine vegetation structures. The conclusion of this comparative modern pollen study allows to interpret fossil sediment spectra from the Near East in a more critical way. It is concluded that one should preferably sample rapidly deposited sediments for palynological analyses, as the resulting highresolution pollen diagrams will be most informative about the former vegetation patterns.     

CARNOY: A new digital measurement tool for palynology

Quantitative data play an important role in palynological research. With the advent of digital imaging in light and electron microscopy, palynologists now have the opportunity to perform measurements faster and more precisely than ever before. Several image analysis software packages already exist for these tasks, but they are often expensive, difficult to use or not adapted to the specific needs of palynologists. After studying the daily workflow of a palynologist, we designed CARNOY, an image analysis application written from the ground up for use in palynology and morphology. CARNOY offers an easy-to-use interface and several features to make measuring easier and faster. The program can export measurements to almost every other software package for further analysis and is available for free on the Internet.     

The manifold characters of orbicules: structural diversity,systematic significance,and vectors for allergens

In the anthers of flowering plants, gymnosperms, and seed ferns, tiny (±1?μm) granules might occur on the radial and innermost tangential wall of secretory tapetum cells. These sporopollenin granules develop simultaneously with the pollen exine and are called orbicules or Ubisch bodies. The present paper focuses on two quite different topics associated with orbicules.

The morphological and ultrastructural diversity of orbicules in the order Gentianales is summarized, and it is demonstrated that orbicules are a plesiomorphic feature in the order. Furthermore, orbicule characters seemed to be correlated with evolutionary trends in pollen dispersal unit and tapetum type features.

In the second part, we report on our investigation of Corylus avellana L. (Hazel) pollen, using immunogold electron microscopy to gain an insight into the possible role that orbicules may play as a vector of pollen allergens. During the pollen season orbicules are dispersed into the atmosphere along with Hazel pollen grains. The localisation of homologues of the new birch pollen allergen Bet v 7 was studied at the subcellular level in Hazel anthers. The results of this study indicate that orbicules and pollen of Hazel might act as very effective vectors for homologues of Bet v 7 and that debris of Hazel anthers represent vectors of allergens after the pollen season.     

A histological study of microsporogenesis in Tarenna gracilipes (Rubiaceae)

We studied the microsporogenesis in Tarenna gracilipes (Hayata) Ohwi, with special attention to the mode of exine deposition and tapetum development. We based this research on light (LM), scanning electron (SEM) and transmission electron microscopic (TEM) observations of developing anthers of T. gracilipes, from the microspore mother cell stage towards anther dehiscence. Evidence is supplied that the microsporogenesis in T. gracilipes can be considered as simultaneous. Columellae, foot layer and tectum develop in a fibrillar matrix. Similar with earlier studies in Rubiaceae species, a single white line formed near the plasmalemma in the extra‐apertural region. The developing endexine dilated into several white line centered lamellae at the apertures. An annulus is formed around the inner surface of each pore. In the mature intine two strata can be distinguished. At the apertures thick onci are formed protruding through the apertures thereby forming papillae, a common feature in Rubiaceae. In Rubiaceae species amoeboid as well as secretory tapeta are reported. In T. gracilipes it is shown that the tapetum cells possess in all developmental stages characteristics of the secretory type. During microsporogenesis the tapetum cytoplasm undergoes considerable changes which may indicate cycles of hyperactivity. Sporopollenin deposition on the pre‐orbicules is mediated by white lines showing correlations with endexine, annulus and columellae ontogeny. These findings corroborate the idea that orbicule wall development can represent a model to study sporopollenin deposition. At anther dehiscence Ca‐oxalate crystals are released out of the ruptured septum cells into the locule, providing a possible visual signal for pollinators.     

Long‐term experimental warming alters community composition of ascomycetes in Alaskan moist and dry arctic tundra

Arctic tundra regions have been responding to global warming with visible changes in plant community composition, including expansion of shrubs and declines in lichens and bryophytes. Even though it is well known that the majority of arctic plants are associated with their symbiotic fungi, how fungal community composition will be different with climate warming remains largely unknown. In this study, we addressed the effects of long‐term (18 years) experimental warming on the community composition and taxonomic richness of soil ascomycetes in dry and moist tundra types. Using deep Ion Torrent sequencing, we quantified how OTU assemblage and richness of different orders of Ascomycota changed in response to summer warming. Experimental warming significantly altered ascomycete communities with stronger responses observed in the moist tundra compared with dry tundra. The proportion of several lichenized and moss‐associated fungi decreased with warming, while the proportion of several plant and insect pathogens and saprotrophic species was higher in the warming treatment. The observed alterations in both taxonomic and ecological groups of ascomycetes are discussed in relation to previously reported warming‐induced shifts in arctic plant communities, including decline in lichens and bryophytes and increase in coverage and biomass of shrubs.     

Leptin activation of mTOR pathway in intestinal epithelial cell triggers lipid droplet formation,cytokine production and increased cell proliferation

Accumulating evidence suggests that obesity and enhanced inflammatory reactions are predisposing conditions for developing colon cancer. Obesity is associated with high levels of circulating leptin. Leptin is an adipocytokine that is secreted by adipose tissue and modulates immune response and inflammation. Lipid droplets (LD) are organelles involved in lipid metabolism and production of inflammatory mediators, and increased numbers of LD were observed in human colon cancer. Leptin induces the formation of LD in macrophages in a PI3K/mTOR pathway-dependent manner. Moreover, the mTOR is a serine/threonine kinase that plays a key role in cellular growth and is frequently altered in tumors. We therefore investigated the role of leptin in the modulation of mTOR pathway and regulation of lipid metabolism and inflammatory phenotype in intestinal epithelial cells (IEC-6 cells). We show that leptin promotes a dose- and time-dependent enhancement of LD formation. The biogenesis of LD was accompanied by enhanced CXCL1/CINC-1, CCL2/MCP-1 and TGF-β production and increased COX-2 expression in these cells. We demonstrated that leptin-induced increased phosphorylation of STAT3 and AKT and a dose and time-dependent mTORC activation with enhanced phosphorilation of the downstream protein P70S6K protein. Pre-treatment with rapamycin significantly inhibited leptin effects in LD formation, COX-2 and TGF-β production in IEC-6 cells. Moreover, leptin was able to stimulate the proliferation of epithelial cells on a mTOR-dependent manner. We conclude that leptin regulates lipid metabolism, cytokine production and proliferation of intestinal cells through a mechanism largely dependent on activation of the mTOR pathway, thus suggesting that leptin-induced mTOR activation may contribute to the obesity-related enhanced susceptibility to colon carcinoma.     

Inoculum effects on community composition and nitritation performance of autotrophic nitrifying biofilm reactors with counter‐diffusion geometry

The link between nitritation success in a membrane‐aerated biofilm reactor (MABR) and the composition of the initial ammonia‐ and nitrite‐oxidizing bacterial (AOB and NOB) population was investigated. Four identically operated flat‐sheet type MABRs were initiated with two different inocula: from an autotrophic nitrifying bioreactor (Inoculum A) or from a municipal wastewater treatment plant (Inoculum B). Higher nitritation efficiencies (NO₂^‐‐N/NH₄⁺‐N) were obtained in the Inoculum B‐ (55.2–56.4%) versus the Inoculum A‐ (20.2–22.1%) initiated reactors. The biofilms had similar oxygen penetration depths (100–150 µm), but the AOB profiles [based on 16S rRNA gene targeted real‐time quantitative PCR (qPCR)] revealed different peak densities at or distant from the membrane surface in the Inoculum B‐ versus A‐initiated reactors, respectively. Quantitative fluorescence in situ hybridization (FISH) revealed that the predominant AOB in the Inoculum A‐ and B‐initiated reactors were Nitrosospira spp. (48.9–61.2%) versus halophilic and halotolerant Nitrosomonas spp. (54.8–63.7%), respectively. The latter biofilm displayed a higher specific AOB activity than the former biofilm (1.65 fmol cell^?1 h^?1 versus 0.79 fmol cell^?1 h^?1). These observations suggest that the AOB and NOB population compositions of the inoculum may determine dominant AOB in the MABR biofilm, which in turn affects the degree of attainable nitritation in an MABR.