Water availability drives stem growth and stem water deficit of <Emphasis Type="Italic">Pinus canariensis</Emphasis> in a drought-induced treeline in Tenerife

Tree growth of Pinus canariensis at treeline in Tenerife, Canary Islands, is thought to be primarily controlled by wet season precipitation (P) prior to the current year´s growth. Therefore, we investigated the inter-annual variations in stem water deficit (ΔW) and radial growth (RG) during two consecutive years differing in wet season P. ΔW was extracted from stem circumference variations, and the influence of environmental variables was evaluated by Pearson correlation statistics. Wet season P was considerably lower in 2008 than in 2009; despite this difference in P between both years, shallow soil water availability was almost exhausted during both summers. However, the effect of shallow soil drought showing a clear seasonality of ΔW and RG was only detected in 2008. In summer 2009, RG rates were highest during the summer indicating that P. canariensis was able to tap water from deep soil layers originating from P prior to the current year´s growth. The ability to use deep soil water during extended periods of shallow soil water deficit was also reflected in a close positive correlation between RG and whole-tree water use. In our study, the effect of only one hydrological dry year resulted in a severe reduction in annual RG. Thus, when wet season P is low for a number of years, chronic drought may have negative implications for tree growth at treeline in Tenerife.     

Trichloroacetate,an inhibitor of wax biosynthesis,prevents the development of hyperhydricity in Arabidopsis seedlings

The study of allelic variations affecting organogenic capacity is not only relevant for manipulating plant traits but also to understand the fundamental mechanisms involved in plant development. Here, we report the characterization of three tomato (Solanum lycopersicum) loci (RG3C, RG7H and RG8F) whose alleles from its wild relative Solanum pennellii enhance in vitro shoot and root regeneration. S. pennellii alleles were introgressed into tomato cv. Micro-Tom (MT), creating near-isogenic lines. We evaluated the time taken for shoot induction and acquisition of competence by quantifying organogenesis after transferring explants, respectively, from the shoot-inducing medium (SIM) to the basal medium (BM) and from root-inducing medium (RIM) to the SIM. Concomitantly, we monitored the expression of key developmental genes. MT-Rg3C and MT-Rg7H started shoot induction, respectively, at 48 and 24 h earlier than MT and MT-Rg8F, while MT-Rg3C and MT-Rg8F acquired competence 24 h before MT. The impact of MT-Rg3C and MT-Rg8F in the acquisition of competence to assume different fates is consistent with their effect enhancing both shoot and root regeneration. MT-Rg7H seems to affect shoot induction specifically, which is in agreement with the enhanced expression of the shoot-related genes WUSCHEL and SHOOT MERISTEMLESS. Phenotypic characterization of greenhouse-grown plants showed that Rg3C has increased branching when compared to MT. Conversely, the normal branching observed in MT-Rg7H and MT-Rg8F indicates that adventitious in vitro shoot formation and ex vitro axillary bud formation/outgrowth are induced by different genetic pathways. These natural variations are thus useful for breeding highly regenerating varieties without undesirable effects on plant architecture.     

Oribatid mites of the superfamily Trizetoidea Ewing, 1917 (Acari,Oribatida) from Peru

Two new species of the oribatid mite superfamily Trizetoidea (Acari, Oribatida) are described from Peru. Rhynchoribates (Rhynchoribatodes) rioyuyapichisensis Ermilov, sp. n. differs from the other species of the subgenus by the long flagelliform notogastral setae. Rhynchoppia puertoincaensis Ermilov, sp. n. is morphologically similar to R. capillata (Balogh, 1963), but differs by the shape and in a greater number of rostral teeth, in the number and a smaller length of notogastral setae, and in the number of genital setae. The genus Rhynchoppia (Balogh 1968) is recorded from the Neotropical Region for the first time, while Rhynchoribates (Rhynchoribatodes) brasiliensis Woas 1986 is new to the fauna of Peru.     

The Effect of Five Biomass Cropping Systems on Soil-Saturated Hydraulic Conductivity Across a Topographic Gradient

Understanding the environmental impact of bioenergy crops is needed to inform bioenergy policy development. We determined the effects of five biomass cropping systems—continuous maize (Zea mays), soybean (Glycine max)-triticale (Triticosecale ×)/soybean-maize, maize-switchgrass (Panicum virgatum), triticale/sorghum (Sorghum bicolor), and triticale-aspen (Populus alba × P. grandidentata)—on soil-saturated hydraulic conductivity (K _S ) across a toposequence in central Iowa, USA. We compared data from the time of cropping system establishment in 2009 to 4 years post-establishment. Both our 2009 and 2013 data confirmed that cropping system impacts on K _S vary by landscape position. We found that differences in cropping system impacts were more likely to occur at lower landscape positions, specifically, within footslope and floodplain positions. Previous research on cropping system impacts suggested that grass and woody systems were associated with a general increase in K _S over time, with greater changes likely occurring at landscape positions with a higher erosive potential or lower SOC content. Our results confirmed that the triticale-aspen woody system was associated with a significant increase in K _S across all landscape positions. In contrast, we did not observe an increase in K _S under maize-switchgrass, which we attributed to the high density of switchgrass roots by the fourth year of study, but expect an increase in K _S under switchgrass under longer measurement periods. We also found a significant increase in K _S in the annual systems, likely due to the conversion to no-till soil management with cropping system establishment. We expect such differences to become more apparent over longer time scales as cropping systems continue to impact soil hydraulic properties.     

The Differentiation of Skin Mesenchymal Stem Cells Towards a Schwann Cell Phenotype: Impact of Sigma-1 Receptor Activation

Neural crest stem cells (NCSCs) are the source of mature Schwann cells in the peripheral nervous system (PNS). The NCSC population resides in the bulge of hair follicles and in the dermis. Recently, it was shown that 2–3% of the human dermis mesenchymal stem cell (MSC) population expresses the NCSC marker CD271, thus enabling the use of skin MSCs for studying Schwann cell differentiation in vitro. The aims of this study were to establish a protocol for human skin MSC differentiation towards Schwann cell-like cells (SC-lcs) and to analyse the expression of sigma-1 receptor (S1R) in SC-lcs. The impact of S1R ligands, namely the selective agonist PRE-084, the positive allosteric modulator E1R and the selective antagonist NE-100, on Schwann cell differentiation was assessed. The expression of the neuron-specific genes Tubulin-βIII and Integrin-6α, the Schwann cell-specific gene S100b, MBP and the NCSC-specific genes p75NTR, Sox10, Notch1, Integrin-4α, Ap2α and Pax6 was analysed in MSCs and SC-lcs by real-time RT-PCR. BDNF secretion was evaluated by ELISA. The effect of S1R ligands on SC-lc differentiation was measured using BDNF ELISA and MBP flow cytometry. After MSC differentiation, NCSC markers p75NTR and Integrin-4α were downregulated 3.5-fold and 2-fold, respectively. To the contrary, MBP and S100b were significantly upregulated in SC-lcs. S1R ligands showed a tendency to increase the secretion of BDNF by the SC-lc population. PRE-084 and E1R increased MBP expression in the SC-lc population, whereas 3 μM NE-100 inhibited MBP expression in SC-lcs. In conclusion, our data demonstrate that S1R plays an important role in skin MSC differentiation towards myelinating Schwann cells.     

An Enigmatic Hypoplastic Defect of the Maxillary Lateral Incisor in Recent and Fossil Orangutans from Sumatra (<Emphasis Type="Italic">Pongo abelii</Emphasis>) and Borneo (<Emphasis Type="Italic">Pongo pygmaeus</Emphasis>)

Developmental dental pathologies provide insight into health of primates during ontogeny, and are particularly useful for elucidating the environment in which extant and extinct primates matured. Our aim is to evaluate whether the prevalence of an unusual dental defect on the mesiolabial enamel of the upper lateral incisor, thought to reflect dental crowding during maturation, is lesser in female orangutans, with their smaller teeth, than in males; and in Sumatran orangutans, from more optimal developmental habitats, than in those from Borneo. Our sample includes 49 Pongo pygmaeus (87 teeth), 21 P. abelii (38 teeth), Late Pleistocene paleo-orangutans from Sumatra and Vietnam (67 teeth), Late Miocene catarrhines Lufengpithecus lufengensis (2 teeth), and Anapithecus hernyaki (7 teeth). Methods include micro-CT scans, radiography, and dental metrics of anterior teeth. We observed fenestration between incisor crypts and marked crowding of unerupted crowns, which could allow tooth-to-tooth contact. Tooth size does not differ significantly in animals with or without the defect, implicating undergrowth of the jaw as the proximate cause of dental crowding and defect presence. Male orangutans from both islands show more defects than do females. The defect is significantly more common in Bornean orangutans (71 %) compared to Sumatran (29 %). Prevalence among fossil forms falls between these extremes, except that all five individual Anapithecus show one or both incisors with the defect. We conclude that maxillary lateral incisor defect is a common developmental pathology of apes that is minimized in optimal habitats and that such evidence can be used to infer habitat quality in extant and fossil apes.     

Two orthologs of late blight resistance gene <Emphasis Type="Italic">R1</Emphasis> in wild and cultivated potato

The R1 gene for resistance to oomycete Phytophthora infestans (Mont.) de Bary, the causal agent of late blight disease of potato (Solanum tuberosum L.), was initially identified in S. demissum and potato varieties bred by introgressing the S. demissum germplasm. Later a sequence characterized amplified region (SCAR) marker R1-1205 of this gene was also found in S. stoloniferum and S. polytrichon. Here we describe the full-length R1 sequence cloned from S. stoloniferum. This sequence is translatable, and this evidence of structural gene integrity is reinforced by functional characterization of the S. stoloniferum R1 gene in an effectoromics experiment. When screened across a series of S. demissum and S. stoloniferum accessions, the R1 sequences differed by several single nucleotide polymorphisms and an indel; this indel served the basis for constructing SCAR markers R1-517 and R1-513 that reliably discerned two R1 orthologs. The demissum-specific marker R1-517 was found in all S. demissum accessions under study; it was also present in many demissum-derived potato varieties and hybrids. The stoloniferum-specific marker R1-513 was found in 27% of S. stoloniferum and S. polytrichon accessions; however, we failed to discern this marker in the genotypes of cultivated potato listing S. stoloniferum in their pedigrees. Most probably, such absence of R1-513 is best explained by an opportunistic breeding history of stoloniferum-derived founder lines, which were employed first and foremost in breeding for resistance to potato virus Y: eventually, these founder lines are devoid of the R1 gene.     

Functional Restoration of Amyotrophic Lateral Sclerosis Patient-Derived Mesenchymal Stromal Cells Through Inhibition of DNA Methyltransferase

Alteration of DNA methylation is highly associated with aging and neurodegenerative disorders, such as amyotrophic lateral sclerosis (ALS). Remedying these aberrant methylation patterns may serve to improve these diseases. Previously, we reported that human bone marrow mesenchymal stromal cells isolated from ALS patients (ALS-MSCs) have functionally decreased stem cell potency, and excessively express DNA methyltransferases (DNMTs). In this study, we examined the correlation between excessive DNMT expression and functional decline in ALS-MSCs. The DNMT inhibitor RG108 was used for this. RG108-treated ALS-MSCs exhibit increased expression of the anti-senescence genes TERT, VEGF, and ANG, and decreased expression of the senescence-related genes ATM and p21. The activity of SA-β-galactosidase and the expression of senescence proteins p53 and p16 were reduced in RG108-treated ALS-MSCs. The abilities of cell migration and protection against oxidative damage were improved in the treated ALS-MSCs. In neuronal differentiation experiments, the treated MSCs more effectively differentiated into neuron-like cells. These results suggest that ALS-MSC function can be restored by inhibiting excessively expressed DNMTs, an approach that may ultimately provide better efficacy in stem cell therapy.     

Analysis of the expression of the <Emphasis Type="Italic">Rhodobacter sphaeroides lexA</Emphasis> gene

The regulation of the Rhodobacter sphaeroides lexA gene has been analyzed using both gel-mobility experiments and lacZ gene fusions. PCR-mediated mutagenesis demonstrated that the second GAAC motif in the sequence GAACN₇GAACN₇GAAC located upstream of the R. sphaeroides lexA gene is absolutely necessary for its DNA damage-mediated induction. Moreover, mutagenesis of either the first or the third GAAC motif in this sequence reduced, but did not abolish, the inducibility of the R. sphaeroides lexA gene. A R. sphaeroides lexA-defective (Def) mutant has also been constructed by replacing the active lexA gene with an inactivated gene copy constructed in vitro. Crude extracts of the R. sphaeroides lexA(Def) strain are unable to form any protein-DNA complex when added to the wild-type lexA promoter of R. sphaeroides. Likewise, the R. sphaeroides lexA(Def) cells constitutively express the recA and lexA genes. All these data clearly indicate that the lexA gene product is the negative regulator of the R. sphaeroides SOS response. Furthermore, the morphology, growth and viability of R. sphaeroides lexA(Def) cultures do not show any significant change relative to those of the wild-type strain. Hence, R. sphaeroides is so far the only bacterial species whose viability is known not to be affected by the presence of a lexA(Def) mutation.     

The morphology and mode of formation of <Emphasis Type="Italic">Neoeione</Emphasis> igen. nov. from the Carboniferous of northern England

Samples of the burrows studied herein, originally introduced as Eione moniliformis Tate, have been collected from the heterolithic sandstone and siltstone beds of a coastal outcrop near the town of Howick, Northumberland, UK. These interbedded and hummocky cross-stratified beds, belonging to the Stainmore Formation, are Carboniferous and represent offshore marine sediment deposited between the fair wave base and storm wave base. As the name Eione was used previously to describe a genus of gastropod, Eione Tate is a junior homonym of Eione Rafinesque. Therefore, a new ichnogenus was established, Parataenidium Buckman, to accommodate burrows composed of two distinct levels, which included E. moniliformis. Using three-dimensional morphological modeling techniques, this study aims to: (1) clarify the current taxonomic status of Parataenidium moniliformis; and (2) provide an updated model for its construction. The transfer of E. moniliformis to Parataenidium was problematic, primarily because it is not composed of two distinct levels, but, instead, is composed of backfilled reniform sediment packages. These packages were created through a multistage process whereby the organism maintained a small open cavity from which it fed. Accordingly, a new ichnogenus, Neoeione, is proposed to accommodate the material originally described by Tate.     

Multigene phylogeny reveals a new species and novel records and hosts in the genus <Emphasis Type="Italic">Ramularia</Emphasis> from Iran

Ramularia is a species-rich genus in the order Capnodiales (Dothideomycetes, Ascomycota) that includes numerous phytopathogenic taxa, several of which are economically important plant pathogens. In this study, six isolates of Ramularia were recovered from leaf spot symptoms on six herbaceous and woody plants from Guilan, East and West Azarbaijan provinces in the north and northwest of Iran. The isolates were studied by a polyphasic approach involving morphological and cultural data, and multi-gene phylogeny (ITS, TEF1-α, ACT, HIS, RPB2 and GAPDH). The isolates were grouped in three species clades of the R. eucalypti species complex. Of these, R. mali is recorded for the first time in Asia and R. glennii represents a new record for the mycobiota of Iran. Ramularia taleshina on Alnus subcordata is described as a new species. Ramularia taleshina is phylogenetically related to R. mali, but they can be differentiated by morphological and cultural characters as well as molecular data. Acalypha australis, Ficus carica and Platanus sp. are reported as new hosts of R. glennii, and Prunus cerasus and Vitis vinifera as new hosts of R. mali.     

Weitere Untersuchungen über Chromosomenverhältnisse und DNS-Gehalt bei Anuren (Amphibia)

The karyotypes of the toad Bufo marinus L. (2n=22) and the frogs Limnodynastes tasmaniensis Gthr. (2n=24), Rana temporaria L., R. esculenta L. (both 2n=26) and R. arvalis Nills. (2n=24) were analysed in colchicine treated leukocyte and spermatogonial metaphases and/or embryonic and larval mitoses. The DNA content of Feulgen stained erythrocyte nuclei was measured microspectrophotometrically. Heteromorphic sex chromosomes are absent in all species. L. tasmaniensis has the lowest DNA content among these species. The south American toad B. marinus shows a karyotype similar to the other known toad species and contains the same amount of DNA as the European species B. calamita with the lowest DNA amount among the European toads. In southern German populations of R. temporaria besides animals with the “standard”-karyotype (2n=26) individuals with 1 or 2, in rare cases with 3 or 4 supernumerary chromosomes have been found. The supernumeraries are heterochromatic and smaller than the smallest chromosome of the “standard”-karyotype. If only 1 or 2 supernumerary chromosomes are present, they seem to show normal mendelian inheritance as a rule. The observation of a few tadpoles with intraindividual different numbers of supernumeraries points to the occurrence of unequal distribution of these chromosomes in individuals containing a higher number of supernumerary chromosomes. The karyotype of R. esculenta is very similar to the “standard”-karyotype of R. temporaria, but the chromosomes of R. esculenta are somewhat longer than those of R. temporaria. R. esculenta contains about 54% more DNA than R. temporaria in the erythrocyte nuclei, so that it must be assumed that all chromosomes of R. esculenta contain more DNA than their homologues in R. temporaria. R. arvalis possesses about 28% more DNA than R. temporaria. It is supposed that these interspecific differences in DNA content of the Rana species — as observed earlier in Bufo species — are not a consequence of differential polyteny but are caused during evolutionary processes by local increase in DNA in the chromosomes of R. esculenta and R. arvalis.     

On some <Emphasis Type="Italic">Rarecostites</Emphasis> (Parkinsoniidae,Ammonoidea) from the Upper Bajocian <Emphasis Type="Italic">Parkinsoni</Emphasis> zone of the Northern Caucasus

The ammonites of the genus Rarecostites (subfamily Parkinsoniinae) are studied from the lower part of the Upper Bajocian Parkinsonia parkinsoni Zone of the Kyafar River (Bolshoi Zelenchuk River Basin, Karachai-Cherkessia, Russia). The locality contains numerous microconch shells of R. subarietis (Wetzel). We follow de Grossouvre (1919) in considering the names R. acris (Wetzel) and R. arietis (Wetzel) to be subjective synonyms of R. subarietis and, thus, the standard Acris should be replaced by the Subarietis Subzone. The lower part of the section also contains numerous microconchs of R. sherstyukovi sp. nov. and, less commonly, macroconchs of R. kyafarensis sp. nov. The phylogeny of Rarecostites species is reconstructed; the above species are described and figured and the sherstyukovi and subarietis faunal horizons are established.     

A strong root-specific expression system for stable transgene expression in bread wheat

Key message

A strong, stable and root-specific expression system was developed from a rice root-specific GLYCINE - RICH PROTEIN 7 promoter for use as an enabling technology for genetic manipulation of wheat root traits.

Abstract

Root systems play an important role in wheat productivity. Genetic manipulation of wheat root traits often requires a root-specific or root-predominant expression system as an essential enabling technology. In this study, we investigated promoters from rice root-specific or root-predominant expressed genes for development of a root expression system in bread wheat. Transient expression analysis using a GREEN FLUORESCENT PROTEIN (GFP) reporter gene driven by rice promoters identified six promoters that were strongly expressed in wheat roots. Extensive organ specificity analysis of three rice promoters in transgenic wheat revealed that the promoter of rice GLYCINE-RICH PROTEIN 7 (OsGRP7) gene conferred a root-specific expression pattern in wheat. Strong GFP fluorescence in the seminal and branch roots of wheat expressing GFP reporter driven by the OsGRP7 promoter was detected in epidermal, cortical and endodermal cells in mature parts of the root. The GFP reporter driven by the promoter of rice METALLOTHIONEIN-LIKE PROTEIN 1 (OsMTL1) gene was mainly expressed in the roots with essentially no expression in the leaf, stem or seed. However, it was also expressed in floral organs including glume, lemma, palea and awn. In contrast, strong expression of rice RCg2 promoter-driven GFP was found in many tissues. The GFP expression driven by these three rice promoters was stable in transgenic wheat plants through three generations (T1–T3) examined. These data suggest that the OsGRP7 promoter can provide a strong, stable and root-specific expression system for use as an enabling technology for genetic manipulation of wheat root traits.

     

Identification,isolation and expression analysis of eight stress-related <Emphasis Type="Italic">R2R3</Emphasis>-<Emphasis Type="Italic">MYB</Emphasis> genes in tartary buckwheat (<Emphasis Type="Italic">Fagopyrum tataricum</Emphasis>)

Key message

Eight R2R3 - MYB genes in tartary buckwheat were identified, and their expression patterns were comprehensively analyzed, which reveals role in plant response to abiotic stresses.

Abstract

The proteins of the R2R3-MYB superfamily play key roles in the growth and development processes as well as defense responses in plants. However, their characteristics and functions have not been fully investigated in tartary buckwheat (Fagopyrum tataricum), a strongly abiotic resistant coarse cereal. In this article, eight tartary buckwheat R2R3-MYB genes were isolated with full-length cDNA and DNA sequences. Phylogenetic analysis of the members of the R2R3-MYB superfamily between Arabidopsis and tartary buckwheat revealed that the assumed functions of the eight tartary buckwheat R2R3-MYB proteins are divided into five Arabidopsis functional subgroups that are involved in abiotic stress. Expression analysis during abiotic stress and exogenous phytohormone treatments identified that the eight R2R3-MYB genes responded to one or more treatments. This study is the first comprehensive analysis of the R2R3-MYB gene family in tartary buckwheat under abiotic stress.

     

GenePattern flow cytometry suite

Background

Traditional flow cytometry data analysis is largely based on interactive and time consuming analysis of series two dimensional representations of up to 20 dimensional data. Recent technological advances have increased the amount of data generated by the technology and outpaced the development of data analysis approaches. While there are advanced tools available, including many R/BioConductor packages, these are only accessible programmatically and therefore out of reach for most experimentalists. GenePattern is a powerful genomic analysis platform with over 200 tools for analysis of gene expression, proteomics, and other data. A web-based interface provides easy access to these tools and allows the creation of automated analysis pipelines enabling reproducible research.

Results

In order to bring advanced flow cytometry data analysis tools to experimentalists without programmatic skills, we developed the GenePattern Flow Cytometry Suite. It contains 34 open source GenePattern flow cytometry modules covering methods from basic processing of flow cytometry standard (i.e., FCS) files to advanced algorithms for automated identification of cell populations, normalization and quality assessment. Internally, these modules leverage from functionality developed in R/BioConductor. Using the GenePattern web-based interface, they can be connected to build analytical pipelines.

Conclusions

GenePattern Flow Cytometry Suite brings advanced flow cytometry data analysis capabilities to users with minimal computer skills. Functionality previously available only to skilled bioinformaticians is now easily accessible from a web browser.

     

Morphological descriptions of the eggcases of skates (Rajidae) from the central-western Mediterranean,with notes on their distribution

Eggcases of eight rajiform skates (Dipturus nidarosiensis, D. oxyrinchus, Leucoraja melitensis, Raja asterias, R. brachyura, R. clavata, R. miraletus and R. polystigma) present in the central-western Mediterranean are described, based on specimens obtained from fishery surveys. Eggcase features such as dimensions, horns and apron lengths, and presence/absence of lateral keels were crucial to discriminate the eggcases of the various species. Morphological and morphometric data, confirmed by the multivariate analysis, indicated that the eggcase of R. miraletus and L. melitensis were distinct from those of the other species for being unkeeled. Within the species having keeled eggcases, those of the genus Dipturus and R. brachyura were discriminated from the remaining group by having the largest dimensions and aprons. Sandy bottoms (<100–150 m depth) were identified as egg-laying sites (i.e. sites with females bearing eggcases in uteri) for many species belonging to genus Raja Raja asterias, R. brachyura, R. miraletus and R. polystigma). The finding of R. asterias and R. miraletus carrying eggcases yearly on the same sites, seems to confirm the theory that many rajid species demonstrate site fidelity, returning to the same depositional area on an annual basis. Some remarks on reproductive biology of these skates are also provided. The eggcase identification key reported here represents the first for the Mediterranean and may be useful, in the future, to identify egg-laying grounds of skates with a nonlethal method.     

Comparative reproductive biology reveals two distinct pollination strategies in Neotropical twig-epiphyte orchids

Members of Oncidiinae are widely known for their interactions with oil-collecting bees that explore lipophilic secretions on flowers. They may also be pollinated through food deception and the offering of nectar. Although data on breeding systems are available for many Oncidiinae orchids, little is known about the reproductive strategies in Rodriguezia, a neotropical genus of ca. 55 species. In this paper, we explore the reproductive biology of two species of Rodriguezia with distinctive morphologies: R. decora and R. lanceolata. Floral features, spectral reflectance, pollinators and pollination mechanisms, and breeding systems were studied. Both species are scentless and produce nectar as a reward. Floral nectar is secreted by a gland at the base of the labellum and stored into the sepaline spur. Rodriguezia decora reflects mainly in the blue and red regions of the light spectrum, while R. lanceolata reflects in the red region. Rodriguezia decora is exclusively visited and pollinated by butterflies, while Trochilidae hummingbirds are the pollinators of R. lanceolata. Pollinaria attach to the upper third of the proboscis of butterflies (R. decora), and to the bill of hummingbirds (R. lanceolata), during the collection of nectar from the spur. Both Rodriguezia species are self-sterile. Flower features and floral reflectance support the occurrence of psychophily in R. decora and ornithophily in R. lanceolata.     

Nutritional symbionts of a putative vector, <Emphasis Type="Italic">Xyleborus bispinatus</Emphasis>, of the laurel wilt pathogen of avocado, <Emphasis Type="Italic">Raffaelea lauricola</Emphasis>

Ambrosia beetles subsist on fungal symbionts that they carry to, and cultivate in, their natal galleries. These symbionts are usually saprobes, but some are phytopathogens. Very few ambrosial symbioses have been studied closely, and little is known about roles that phytopathogenic symbionts play in the life cycles of these beetles. One of the latter symbionts, Raffaelea lauricola, causes laurel wilt of avocado, Persea americana, but its original ambrosia beetle partner, Xyleborus glabratus, plays an uncertain role in this pathosystem. We examined the response of a putative, alternative vector of R. lauricola, Xyleborus bispinatus, to artificial diets of R. lauricola and other ambrosia fungi. Newly eclosed, unfertilized females of X. bispinatus were reared in no-choice assays on one of five different symbionts or no symbiont. Xyleborus bispinatus developed successfully on R. lauricola, R. arxii, R. subalba and R. subfusca, all of which had been previously recovered from field-collected females of X. bispinatus. However, no development was observed in the absence of a symbiont or on another symbiont, Ambrosiella roeperi, recovered from another ambrosia beetle, Xylosandrus crassiusculus. In the no-choice assays, mycangia of foundress females of X. bispinatus harbored significant colony-forming units of, and natal galleries that they produced were colonized with, the respective Raffaelea symbionts; with each of these fungi, reproduction, fecundity and survival of the beetle were positively impacted. However, no fungus was recovered from, and reproduction did not occur on, the A. roeperi and no symbiont diets. These results highlight the flexible nature of the ambrosial symbiosis, which for X. bispinatus includes a fungus with which it has no evolutionary history. Although the “primary” symbiont of the neotropical X. bispinatus is unclear, it is not the Asian R. lauricola.     

Early Cretaceous mammals of Western Siberia: 2. Tegotheriidae

New specimens of the tegotheriid docodont Sibirotherium rossicum Maschenko et al., 2003, including a maxillary fragment with two posterior teeth, an isolated upper molar, and mandibular fragments with teeth from the Early Cretaceous Shestakovo locality are described. The dental formula of Sibirotherium is I_{1 + ?}C1P₆M_6?. The upper molars of Sibirotherium, with two main labial and three lingual cusps, are convergently similar to the molars of tribosphenic mammals. In the dentary, the symphysis is short and Meckel’s groove is reduced. Sibirotherium is similar in the structure of lower teeth to Tegotherium from the Upper Jurassic of Mongolia; it is the latest known representative of Docodonta.