TRANSPORT OF GLUTATHIONE S-CONJUGATES IN THE YEASTSSACCHAROMYCES CEREVISIAE

Transport of 2,4-dinitrophenyl-S-glutathione (DNP-SG) and a fluorescent glutathione S-conjugate, bimane-S-glutathione (B-SG) was studied in the baker's yeasts (S. cerevisiae). Both conjugates were exported from the cells; the transport was inhibited by fluoride and vanadate like in mammalian cells. B-SG was also found to be accumulated in the vacuoles. The transport rate of DNP-SG outside the cell was higher in a vacuolar-deficient strain. A significant ATP-dependent uptake of (³H)-DNP-SG by vacuoles was found. These results indicate thatS. cerevisiaetransport glutathione S-conjugates both outside the cells and into the vacuoles.     

Structure and distribution of floral trichomes in Lycaste and Sudamerlycaste (Orchidaceae: Maxillariinae s.l.)

Phylogenetic analysis indicates that Lycastinae should be incorporated into a more broadly defined Maxillariinae. This is supported by several anatomical features, including the presence of sunken, glandular trichomes in both Lycastinae and Maxillariinae s.s. Until recently, these were known only from vegetative organs, but have since been reported from flowers of Maxillaria dichroma. One character currently used to distinguish between Lycaste and Sudamerlycaste is the distribution of floral trichomes. In this article, we test the reliability of this character, describe the floral micromorphology of Lycaste and Sudamerlycaste and investigate whether their flowers bear sunken hairs. Their floral micromorphology is compared with that of other genera currently assigned to Maxillariinae s.l. Flowers of Lycaste and Sudamerlycaste bear conical or obpyriform papillae and unbranched and unequally branched multicellular trichomes. Contrary to previous reports that trichomes are confined to the column in Sudamerlycaste, they also occur in the tepal axils. Labellar trichomes, although often present in Lycaste, are lacking in Sudamerlycaste. In Lycaste sections Lycaste and Aromaticae, floral trichomes tend to be unbranched, whereas section Intermediae has both unbranched and branched hairs. Branched hairs are more common in Sudamerlycaste. Some hairs are tracheoidal, pitted and lignified. These mainly occur in section Lycaste and, to a degree, in section Intermediae, but are absent from section Aromaticae and most species of Sudamerlycaste. Branched column hairs, present in Sudamerlycaste, are absent from all sections of Lycaste, and tracheoidal column hairs occur only in Sudamerlycaste. Sunken floral hairs are absent from both genera. Trichome structure and distribution may prove useful in distinguishing between these taxa and in elucidating the intergeneric relationships of Maxillariinae s.l.© 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 409–421.     

Shoot anatomy and secretory structures in Hypericum species (Hypericaceae)

The anatomy and ultrastructure of internodes, leaves and petals were compared in Hypericum elegans, H. inodorum, H. olympicum, H. forrestii and two genotypes of H. perforatum. Internode anatomy was variable between species with respect to the structure of the cortical and pith parenchyma, including the presence of secretory reservoirs. Also, the secondary growth was more extensive in shrubs, i.e. H. inodorum and H. forrestii. In leaves, phloem secretory reservoirs were formed in all species, mesophyll secretory reservoirs were absent only in H. elegans and internal nodules were present only in H. elegans and H. perforatum. The petals differed between species in the mesophyll structure and the occurrence and location of secretory structures. The phloem secretory reservoirs lacked sheaths, whereas these were distinct in the mesophyll reservoirs. Other ultrastructural traits of the reservoirs were similar in all the species studied, with the exception of the leucoplast ultrastructure. In internal nodules, the inner cells vs. sheath cells differed in the number of vesicles and other membranous structures and plastid ultrastructure. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 70–86.     

Cryptic hybrids between Pinus uncinata and P. sylvestris

We tested the performance of molecular markers and biometric traits in the identification of hybrids between closely related mountain pine (Pinus uncinata) and Scots pine (Pinus sylvestris). A plastid DNA marker and a set of morphological and anatomical needle traits were applied in analyses of individuals from several sympatric stands of the species and a single‐species' population from southern Europe, used as a reference. A polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) marker from the plastid trnL–trnF region and morphological and anatomical traits clearly discriminated between the pure species. Significant differences were found between P. uncinata and P. sylvestris, mostly in the shape of epidermal cells and the number of stomata. Four putative hybrids with P. sylvestris morphology, but with P. uncinata plastid DNA haplotypes, were found in a population from Sierra de Gúdar near Valdelinares, the southernmost locality of the latter species in eastern Spain. Discrimination analyses between and within populations placed these individuals on the edge of an agglomeration of P. sylvestris individuals. The results suggest that hybridization between the species is rare, but can result in cryptic hybrids morphologically similar to the maternal species. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 473–485.     

Genetic diversity of Philaenus spumarius and P. tesselatus (Hemiptera,Aphrophoridae): implications for evolution and taxonomy

The meadow spittlebugs Philaenus spumarius and P. tesselatus are closely related taxa with uncertain taxonomic position in the light of previous morphological, ecological, cytological and molecular research. Despite morphological homogeneity of P. spumarius (with the exception of high colour and pattern polymorphism) across its wide Holarctic range, it is possible that additional taxa (species or subspecies) exist. Philaenus spumarius is a potentially important pest in parts of its range where it was introduced. We used DNA markers to describe the genetic diversity of P. spumarius and P. tesselatus and to verify the taxonomic status of P. tesselatus and remote populations of the former species. The mitochondrial (cytochrome B) data showed that there are two main groups encompassing a northeastern (Asia and north‐central Europe) and a southwestern (Mediterranean area and western Europe, including North American specimens) clade. According to the elongation factor‐1α gene, there are three main clades: northeastern (Eurasiatic clade, E1), southeastern (east Mediterranean – Caucasus clade, E2) and southwestern (Iberian clade, E3). These two or three mitochondrial and nuclear clades could be considered as separate taxonomic units. On the other hand, all studied individuals of both species possessed the same internal transcribed spacer 2 haplotype. American specimens most probably originated from some western European populations. All studied specimens of P. tesselatus belong to the southwestern clade and western Mediterranean cluster. Therefore, together with cytological data, its species status is doubtful. To definitively solve the taxonomic status of P. tesselatus and populations of P. spumarius, further research using more samples and more genetic markers are needed.     

A Novel Healing Filament in Ciliate Regeneration

The interphase cells of the hypotrich ciliate Paraurostyla weissei possess a complex fibrillar system surrounding basal bodies in the compound ciliary assemblages, cirri and membranelles. During replacement of the ciliature at cell division, transient filaments precede and accompany the development of ciliary primordia and participate in the formation of the fission furrow. Both fibrillar systems are recognized by monoclonal antibody FXXXIX 12G9. We studied regeneration of cellular fragments after transection employing the mAb 12G9 and found a new cytoskeletal structure involved in healing of the excisional wound. The healing filament is formed at the wound edge, distally and in connection with the bases of cirri closest to the wound. It is visible 5 min after transection. Concomitant with development of new ciliary primordia, the healing filament shrinks and finally disappears together with other transient fibers formed in this process. Ultrastructural analysis of immunolabeled regenerating cells revealed that structures recognized by mAb 12G9 contain fine filaments whose packing and arrangement depends on accompanying cytoplasmic elements and the developmental status of a fragment. Assembly of the healing fiber does not depend on microtubules and microfilaments since it develops in cellular fragments exposed to cold, nocodazole, and Cytochalasin D. On Western blots of whole cell and cytoskeletal extracts of P. weissei the 12G9 antibody identified one protein band whose molecular weight corresponds to 60 kDa.     

To be or not to be a valid genus: the systematic position of Ophyra R.‐D. revised (Diptera: Muscidae)

Ophyra Robineau‐Desvoidy is one of the better‐studied genera of the family Muscidae (Diptera). The larvae of species of this genus feed on highly decomposed organic matter of various origins, and may reveal predatory behaviour as they mature. These feeding habits, combined with the widespread distribution and close association with human dwellings of some species, give the genus commercial and medico‐legal importance. However, the systematic position of Ophyra has been a matter of debate for many years. Ophyra has been considered by muscid workers to be either a valid genus or a junior synonym of Hydrotaea Robineau‐Desvoidy. A lack of agreement about the systematic position of Ophyra has led to serious errors, particularly in the applied literature. Recent molecular and morphological studies provided contradictory information on the validity of the genus and its subfamilial classification. We revise the systematic position of Ophyra herein by means of molecular phylogenetic reconstruction. Our results are incongruent with opinions on the systematic position of Ophyra based on previously published molecular phylogenies, although they correspond with the concept of the genus based on adult morphology. All analyses of the concatenated dataset revealed Ophyra as monophyletic and placed within a paraphyletic Azeliini. Depending on the phylogenetic approach, Ophyra was placed within either a monophyletic, paraphyletic or polyphyletic Hydrotaea, yet always closely related to a certain group of species. We conclude that Ophyra, as currently defined, should not be considered a valid name, yet a detailed reconstruction of the genus Hydrotaea awaits future studies with greater increases in both taxon sampling and the number of molecular markers.     

Molecular studies resolve Nyholmiella (Orthotrichaceae) as separated genus

Two Orthotrichum species of the subgenus Orthophyllum were compared with other representatives of this genus using the internally transcribed spacer regions 1 and 2, the chloroplast trnH-psbA region and ISSR and ISJ DNA markers. The applied DNA markers revealed many bands and mutations specific only to O. gymnostomum and O. obtusifolium. A phylogenetic analysis clearly supported the previous concepts postulating that species of the subgenus Orthophyllum should be recognized as separate genus Nyholmiella.     

Microconchid tubeworms across the upper Frasnian – lower Famennian interval in the Central Devonian Field,Russia

Abstract: Microconchid tubeworms (Tentaculita) encrusting brachiopod shells have been investigated from the upper Frasnian – lower Famennian (Upper Devonian) deposits of the Central Devonian Field, Russia. The condition of microconchids and associated encrusting taxa is reported for the first time from the early Famennian recovery interval (crepida Chron) following the Frasnian–Famennian mass extinction. Two species, one new (Palaeoconchus variabilis sp. nov.) and the second one in open nomenclature (Palaeoconchus sp.), are described. Compared to lower Famennian specimens, they seem to be preferentially grouped on the anterior parts of the brachiopod host shells, which are interpreted as the most suitable sites away from the sea‐bottom and sediment. During the late Frasnian (Late rhenana Chron), microconchids, outnumbered by cornulitids and as abundant as foraminifers, were also associated with trepostome bryozoans, tabulates, rugose corals and various problematic encrusters. During the early Famennian recovery interval encompassing the crepida Chron, microconchids greatly outnumbered all associated encrusters, including the previously dominant cornulitids, while foraminifers, tabulates and rugose corals vanished. Early Famennian microconchids, represented by the single, albeit very abundant, species Palaeoconchus variabilis sp. nov., were opportunists that rapidly colonised the environment during the ongoing transgression following the regression‐driven biotic crisis in the area of the Central Devonian Field. In comparison to their late Frasnian predecessors and even other Middle Devonian specimens, no size reduction (the so‐called Lilliput effect) of early Famennian microconchid tubes was observed. It is probable that microconchids either rapidly attained their ‘normal’ sizes or they did not suffer any dwarfism following the Frasnian–Famennian event.